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Characterization of an Australian outbreak Japanese Encephalitis virus genotype 4 isolate in mice and human cortical brain organoids

BackgroundHuman infections with Japanese encephalitis virus (JEV) are a leading cause of viral encephalitis. An unprecedented outbreak of JEV genotype 4 was recently reported in Australia, with an isolate (JEVNSW/22) obtained from a stillborn piglet brain. MethodsHerein we compared the neuropathology of JEVNSW/22, JEVFU (genotype 2) and JEVNakayama (genotype 3) in adult C57BL/6J wild-type mice, mice deficient in interferon regulatory factor 7 (Irf7-/-), and mice deficient in type I interferon receptor (Ifnar-/-), as well as in human cortical brain organoids (hBOs). Using human serum post-Imojev vaccination, we performed neutralisation assays to determine JEVNSW/22 susceptibility to vaccine responses. FindingsIn C57BL/6J and Irf7-/- mice with lethal outcomes, brain infection and histopathological lesions recapitulated those seen in humans and primates. JEV was universally lethal in Ifnar-/- mice by day 3 with histological signs of brain hemorrhage, but produced no other detectable brain infection or lesions, with viral protein detected in blood vessels but not neurons. We thus describe a new Irf7-/- mouse model for JEVNSW/22, which had increased viremia compared to C57BL/6J mice, allowing for lethal neuroinvasive infection in one mouse. Overall, JEVNSW/22 was less neurovirulent than other JEV isolates in C57BL/6J and Irf7-/- mice, and was more sensitive to type I interferon. All JEV isolates showed robust cytopathic infection of human cortical brain organoids, albeit lower for JEVNSW/22. We also show that Imojev vaccination in humans induced neutralizing antibodies against JEVNSW/22, with the level of cross-neutralisation related to the conservation in envelope protein amino acid sequences for each isolate. InterpretationOur study establishes JEVNSW/22 mouse models of infection, allowing for possible lethal neuroinvasive infection that was rarer than for other JEV genotypes. JEV vaccination regimens may afford protection against this newly emerged JEV genotype 4 strain, although neutralizing antibody responses are sub-optimal. FundingQIMRB received a generous philanthropic donation from the Brazil Family Foundation awarded to D.J.R. to support Japanese Encephalitis virus research at QIMRB. A.S. holds an Investigator grant from the National Health and Medical Research Council (NHMRC) of Australia (APP1173880). We also acknowledge the intramural grant from QIMR Berghofer awarded to R.S. and D.J.R. for purchase of the CelVivo Clinostar incubator for producing human cortical brain organoids. The project "Japanese encephalitis vaccine via the intradermal route in children and adults (JEVID-2): A clinical trial comparing the immunogenicity and safety of Japanese encephalitis vaccine administered by subcutaneous and intradermal routes" being conducted by G.D., N.G., and N.W. was funded by the Sydney Childrens Hospitals Network and New South Wales Health. Research in context Evidence before the studyJEV from the historically rare genotype 4 recently emerged in Australia, causing an unprecedented outbreak, with 44 human cases and 7 fatalities. While a range of JEV mouse models have been reported, none of them infect adult mice with a genotype 4 isolate. The efficacy of current vaccines for this JEV genotype are also unclear. Added value of this studyWe establish well characterised adult and subcutaneously infected mouse models for JEV which recapitulate many aspects of human disease including lethal neuroinvasive infection and severe histopathological lesions. Prolonged viremia was significantly associated with lethal neuroinvasiveness in Irf7-/-mice. We demonstrate that a genotype 4 Australian isolate, JEVNSW/22, exhibited markedly diminished lethal neuroinvasion compared to other JEV genotypes. Using serum from Imojev vaccine recipients, neutralizing antibodies against JEVNSW/22 were present, albeit at sub-optimal titers. Implications of all the available evidenceThe establishment of well characterised adult mouse models of JEVNSW/22 with rare neuropenetrance after peripheral inoculation that recapitulate human disease is an important tool that can now be deployed in pre-clinical studies and to understand disease pathogenesis. Our study suggests that new vaccines should be developed against circulating JEV strains for optimal neutralizing antibody responses.

microbiology↗

Antibody-mediated rescue of endogenous retrovirus-induced damage in the demyelinated central nervous system

The human endogenous retrovirus type W (HERV-W) has been identified as a human-specific neuropathological factor that preferentially affects glial cell types in multiple sclerosis (MS). Recent work using transgenic mice with expression of the HERV-W envelope (ENV) protein unveiled that this endogenous retroviral element disrupts myelin repair and polarizes microglial and astroglial cells towards axon-damaging neurotoxic phenotypes. Moreover, initial clinical trials using Temelimab, a neutralizing antibody targeting the HERV-W ENV protein, have provided circumstantial evidence that ENV exerts anti-regenerative and neurodegenerative effects in MS patients. Aligning these observations, it was therefore concluded that HERV-W represents an important factor contributing to disease progression independent of relapse activity (PIRA). Building on these findings, we here applied a neutralizing anti-ENV antibody in a non-inflammatory demyelination mouse model to directly evaluate its potential to mitigate neurodegeneration and ameliorate remyelination. In transgenic mice with human-specific expression of the HERV-W ENV protein, repetitive intraperitoneal anti-ENV antibody injections resulted in accelerated oligodendroglial differentiation, enhanced remyelination, axonal protection, and reduced neurofilament light chain leakage in the serum. Neurotoxic microglial traits were also reduced, while homeostatic parameters were stabilized. As astroglial cells underwent a similar shift, inducing regenerative traits at the expense of toxic parameters, anti-ENV application overall generated a less hostile cellular environment. This study provides direct evidence of the capacity of HERV-W neutralizing antibodies to access the central nervous system and to ameliorate damage conferred by this viral entity previously associated with smouldering disease processes. Significance StatementAlthough neurodegeneration is a hallmark of multiple sclerosis (MS), its underlying mechanisms are poorly understood. Clinically, it manifests as smouldering MS or progression without relapse activity (PIRA). This is the primary factor leading to the accumulation of clinical disability and is currently untreatable. This study provides the first direct evidence that antibodies directed against the HERV-W ENV protein can attenuate the activity of neurodegeneration-promoting glial cells in vivo. Our data validates neutralization of this endogenous retroviral element as a promising therapeutic approach particularly relevant to the chronic form of MS.

neuroscience↗

The amyloid oligomer modulator anle138b has disease modifying effects in a human IAPP transgenic mouse model of type 2 diabetes mellitus (hIAPP Ob/Ob mice)

Aims/HypothesisType 2 diabetes mellitus (T2DM) is a common metabolic disease, characterized by impaired insulin action, often called "insulin resistance", in conjunction with a decline in insulin secretion by the pancreatic islet beta cells, referred to as "beta cell failure". Both conditions contribute to causing hyperglycemia, which is the central feature of T2DM. Cytotoxic aggregates of the beta cell hormone human islet amyloid polypeptide (hIAPP), promote T2DM pathogenesis by damaging the pancreatic islet beta cells and reducing insulin secretion. Anle138b is an amyloid oligomer modulator with demonstrated disease-modifying properties in mouse models of neurodegenerative diseases linked to protein aggregation, and is currently in a phase 2 clinical trial. We therefore tested whether anle138b can reduce hyperglycemia in a severe hIAPP transgenic mouse model of T2DM. MethodsAnle138b was administered orally via dietary admixture to male hIAPP Ob/Ob mice and Ob/Ob controls; blood glucose-, insulin-, and glycated hemoglobin (HbA1c) levels were measured at different timepoints over 34 weeks; in addition, the effects of anle138b on the histomorphology of the pancreatic islets was determined. Finally, anle138b effects on mitochondrial toxicity of hIAPP aggregates was assessed in vitro. ResultsOral administration of anle138b in male hIAPP Ob/Ob mice potently reduced hyperglycemia and glycated HbA1c levels compared to non-treated mice (at 34 weeks, mean glucose level non-treated: 30 {+/-} 1.3 mM, treated: 15 {+/-} 2.2 mM (p < 0.001); at 32 weeks, mean HbA1c level non-treated: 77 {+/-} 3.3 mM/M, treated: 41 {+/-} 5.3 mM/M (p < 0.01)), in a hIAPP-dependent way. In addition, anle138b increased both the number of pancreatic islets as well as the overall islet beta cell mass (by 54% and 58%, respectively) in hIAPP Ob/Ob mice. In vitro, anle138b inhibited toxic effects of hIAPP on mitochondria, such as mitochondrial swelling (decreased by 92%, p < 0.01), release of cytochrome c (decreased by 63.7%, p < 0.001) and lowered mitochondrial membrane potential (increased by 62%, p < 0.001). Conclusions/InterpretationCollectively, our results indicate that anle138b is a promising clinical drug candidate for preserving islet function and reducing hyperglycemia in T2DM, in part by mitigating mitochondrial dysfunction. Research in ContextO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LIType 2 diabetes mellitus (T2DM) is characterized by hyperglycemia, which stems from impaired insulin action coupled with declining insulin secretion from pancreatic islet beta cells. C_LIO_LIAggregation of the beta cell hormone human islet amyloid polypeptide (hIAPP) plays a crucial role in the loss and dysfunction of the insulin-secreting beta cells. C_LIO_LIThe small-molecule anle138b effectively modulates the aggregation of amyloidogenic proteins in neurodegenerative conditions such as Alzheimers and Parkinsons disease. C_LI What is the key question?O_LICan the oligomer modulator anle138b ameliorate the diabetic phenotype in a severe hIAPP transgenic mouse model of T2DM (hIAPP Ob/Ob) ? C_LIO_LIWhat are the new findings? C_LIO_LIOral treatment of hIAPP Ob/Ob mice with anle138b causes reduced hyperglycemia and reduced glycated hemoglobin (HbA1c) levels, in a hIAPP-dependent manner. C_LIO_LIAnle138b increases pancreatic islet number and beta cell mass and restores the inverse relation between insulin and glucose in hIAPP Ob/Ob mice. C_LIO_LIIn vitro anle138b inhibits toxic effects of hIAPP aggregates on mitochondria. C_LI How might this impact on clinical practice in the foreseeable future?O_LIAnle138b could be introduced as a promising clinical drug candidate for slowing down disease progression of T2DM. C_LI

pathology↗

PTPRZ1-targeting RNA CAR-T cells exert antigen-specific and bystander antitumor activity in glioblastoma

The great success of chimeric antigen receptor (CAR)-T cell therapy in B-cell malignancies has prompted its translation to solid tumors. In the case of glioblastoma (GBM), clinical trials have shown modest efficacy, but anti-GBM CAR-T cells are being intensely developed. In this study, we selected PTPRZ1 as an attractive new target for GBM treatment. We isolated six anti-human PTPRZ1 scFv from a human phage display library and produced 2nd generation CAR-T cells in an RNA format. Patient-derived GBM PTPRZ1-knock-in cell lines were used to select the CAR construct (471_28z), which showed high cytotoxicity while consistently displaying high CAR expression. CAR-T cells incorporating 471_28z were able to release IFN-{gamma}, IL-2, TNF-, Granzyme B, IL-17A, IL-6, and soluble FasL, and displayed low tonic signaling. Additionally, they maintained an effector memory phenotype after in vitro killing. Importantly, 471_28z CAR-T cells displayed strong bystander killing against PTPRZ1-negative cell lines after pre-activation by PTPRZ1-positive tumor cells, but did not kill antigen-negative non-tumor cells. In an orthotopic xenograft tumor model using NSG mice, a single dose of anti-PTPRZ1 CAR-T cells significantly delayed tumor growth. Taken together, these results validate the use of PTPRZ1 as a new GBM target and prompt the use of anti-PTPRZ1 CAR-T cells for clinical translation.

immunology↗

Immunotherapy of cytomegalovirus infection by low-dose adoptive transfer of antiviral CD8 T cells relies on substantial post-transfer expansion of central memory cells but not effector-memory cells

Cytomegaloviruses (CMVs) are host species-specific in their replication. It is a hallmark of all CMVs that productive primary infection is controlled by concerted innate and adaptive immune responses in the immunocompetent host. As a result, the infection usually passes without overt clinical symptoms and develops into latent infection, referred to as latency. During latency, the virus is maintained in a non-replicative state from which it can reactivate to productive infection under conditions of waning immune surveillance. In contrast, infection of an immunocompromised host causes CMV disease with viral multiple-organ histopathology resulting in organ failure. Primary or reactivated CMV infection of hematopoietic cell transplantation (HCT) recipients in a "window of risk" between therapeutic hematoablative leukemia therapy and immune system reconstitution remains a clinical challenge. Studies in the mouse model of experimental HCT and infection with murine CMV (mCMV), followed by clinical trials in HCT patients with human CMV (hCMV) reactivation, have revealed a protective function of virus-specific CD8 T cells upon adoptive cell transfer (AT). Memory CD8 T cells derived from latently infected hosts are a favored source for immunotherapy by AT. Strikingly low numbers of these cells were found to prevent CMV disease, suggesting either an immediate effector function of few transferred cells or a clonal expansion generating high numbers of effector cells. In the murine model, the memory population consists of resting central memory T cells (TCM), as well as of conventional effector-memory T cells (cTEM) and inflationary effector-memory T cells (iTEM). iTEM, increase in numbers over time in the latently infected host, a phenomenon known as memory inflation (MI). They thus appeared to be a promising source for use in immunotherapy. However, we show here that iTEM contribute little to the control of infection after AT, which rests almost exclusively on a superior proliferation potential of TCM. Author SummaryImmunotherapy of reactivated cytomegalovirus infection in immunocompromised HCT recipients by adoptive transfer (AT) of antiviral CD8 T cells is the last resort to fight virus variants that have acquired resistance to standard antiviral drugs. Provision of cell numbers high enough for clearance of productive infection remains a logistical limitation for AT to become clinical routine. Although use of donor memory CD8 T cells has become the standard in clinical AT, little is known about the relative antiviral efficacies of memory CD8 T-cell activation subsets, such as central memory cells (TCM) and different populations of effector-memory cells (TEM). A reliable quantitative comparison of the antiviral efficacies of memory CD8 T-cell subsets is precluded in clinical investigation, because independent cohorts of AT donors and AT recipients unavoidably differ in many genetical, immunological, and virological variables. Therefore, this is a question for which a preclinical animal model is predestined. We show here in the well-established mouse model of low-dose AT that CMV infection is by far most efficiently controlled by virus-specific TCM, based on a superior potential to proliferate even in extra-lymphoid tissue to prevent virus spread. For clinical AT, our data provide an argument to favor transfer of sorted TCM rather than TEM.

immunology↗

Context-dependent roles for autophagy in myeloid cells in tumor progression

Autophagy is known to suppress tumor initiation by removing genotoxic stresses in normal cells. Conversely, autophagy is also known to support tumor progression by alleviating metabolic stresses in neoplastic cells. Centered on this pro-tumor role of autophagy, there have been many clinical trials to treat cancers through systemic blocking of autophagy. Such systemic inhibition affects both tumor cells and non-tumor cells, and the consequence of blocked autophagy in non-tumor cells in the context of tumor microenvironment is relatively understudied. Here, we examined the effect of autophagy-deficient myeloid cells on the progression of autophagy-competent tumors. We found that blocking autophagy only in myeloid cells modulated tumor progression markedly but such effects were context dependent. In a tumor implantation model, the growth of implanted tumor cells was substantially reduced in mice with autophagy-deficient myeloid cells; T cells infiltrated deeper into the tumors and were responsible for the reduced growth of the implanted tumor cells. In an oncogene-driven tumor induction model, however, tumors grew faster and metastasized more in mice with autophagy- deficient myeloid cells. These data demonstrate that the autophagy status of myeloid cells plays a critical role in tumor progression, promoting or suppressing tumor growth depending on the context of tumor-myeloid cell interactions. This study indicates that systemic use of autophagy inhibitors in cancer therapy may have differential effects on rates of tumor progression in patients due to effects on myeloid cells and that this warrants more targeted use of selective autophagy inhibitors in a cancer therapy in a clinical setting.

cancer biology↗

Ropinirole hydrochloride mitigates oxidative stress and neuroinflammation via the PI3K-mTOR pathway in TDP-43 hiPSC-derived microglial-like cells

BackgroundAmyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder characterized by progressive motor neuron loss accompanied by neuroinflammation, oxidative stress, and impaired proteostasis, with pathological aggregation of TDP-43 as its defining hallmark. Microglia are recognized as central contributors to ALS pathogenesis, yet the mechanisms underlying their intrinsic dysfunction in the context of TDP-43 remain insufficiently characterized. MethodsWe characterized microglia-like cells (iMGLs) differentiated from isogenic TDP-43 M337V human induced pluripotent stem cell lines. We performed integrated functional assays, transcriptomic profiling and drug repurposing analysis to systematically compare mutant and control iMGLs. To assess therapeutic potential, we evaluated the effects of ROPI, a dopamine D2 receptor agonist previously advanced to clinical trials for ALS, on disease-relevant phenotypes in TDP-43 iMGLs. ResultsTDP-43M337V/M337V iMGLs presented ALS-associated abnormalities, including cytoplasmic TDP-43 accumulation with impaired phagocytosis and elevated oxidative stress, impaired autophagy and mitophagy, altered cytokine profiles, and reduced ferritin levels. Building on our previous identification of ropinirole hydrochloride as neuroprotective for ALS motor neurons, we now show that it confers therapeutic benefits in mitigating microglial pathology. ROPI treatment significantly reduced oxidative stress and caspase-3/7 activity and partially restored cytokine homeostasis in TDP-43M337V/M337V iMGLs, independent of autophagy/mitophagy modulation. Transcriptomic profiling revealed that ropinirole modulated disease-associated gene expression signatures involving protein folding, extracellular matrix organization, and oxidative stress responses. Furthermore, connectivity map-based analysis prioritized PI3K-Akt-mTOR inhibitors as candidates for reversing TDP-43 iMGL signatures, and ropinirole was found to modulate mTOR signaling. These converging lines of evidence support a mechanistic role for ropinirole in restoring microglial homeostasis via PI3K-mTOR pathway regulation. Taken together, our findings position ropinirole as a promising candidate dual action therapeutic candidate capable of targeting both neuronal and microglial dysfunction in ALS, suggesting broader applicability of ropinirole in modulating neuroinflammatory cascades across other neurodegenerative conditions. ConclusionRopinirole broadens ALS therapy from motor neurons to microglia, underscoring its promise for integrated and clinically meaningful treatment strategies.

neuroscience↗

Novel regimens of bedaquiline-pyrazinamide combined with moxifloxacin, rifabutin, delamanid and/or OPC-167832 in murine tuberculosis models

A recent landmark trial showed a 4-month regimen of rifapentine, pyrazinamide, moxifloxacin and isoniazid (PZMH) to be non-inferior to the 6-month standard of care. Here, two murine models of tuberculosis were used to test whether novel regimens replacing rifapentine and isoniazid with bedaquiline and another drug would maintain or increase the sterilizing activity of the regimen. In BALB/c mice, replacing rifapentine in the PZM backbone with bedaquiline (i.e., BZM) significantly reduced both lung CFU counts after 1 month and the proportion of mice relapsing within 3 months after completing 1.5 months of treatment. Addition of rifabutin to BZM (BZMRb) further increased the sterilizing activity. In the C3HeB/FeJ mouse model characterized by caseating lung lesions, treatment with BZMRb resulted in significantly fewer relapses than PZMH after 2 months of treatment. A regimen combining the new DprE1 inhibitor OPC-167832 and delamanid (BZOD) also had superior bactericidal and sterilizing activity compared to PZM in BALB/c mice and was similar in efficacy to PZMH in C3HeB/FeJ mice. Thus, BZM represents a promising backbone for treatment-shortening regimens. Given the prohibitive drug-drug interactions between bedaquiline and rifampin or rifapentine, the BZMRb regimen represents the best opportunity to combine, in one regimen, the treatment-shortening potential of the rifamycin class with that of BZM and deserves high priority for evaluation in clinical trials. Other 4-drug BZM-based regimens and BZOD represent promising opportunities for extending the spectrum of treatment-shortening regimens to rifamycin- and fluoroquinolone-resistant tuberculosis.

microbiology↗

The fiber knob protein of human adenovirus type 49 mediates highly efficient and promiscuous infection of cancer cell lines using a novel cell entry mechanism

The human adenovirus (HAdV) phylogenetic tree is diverse, divided across seven species and comprising over 100 individual types. Species D HAdV are rarely isolated with low rates of pre-existing immunity, making them appealing for therapeutic applications. Several species D vectors have been developed as vaccines against infectious diseases where they induce robust immunity in pre-clinical models and early phase clinical trials. However, many aspects of the basic virology of species D HAdV, including their basic receptor usage and means of cell entry, remain understudied. Here, we investigated HAdV-D49, which previously has been studied for vaccine and vascular gene transfer applications. We generated a pseudotyped HAdV-C5 presenting the HAdV-D49 fiber knob protein (HAdV-C5/D49K). This pseudotyped vector was efficient at infecting cells devoid of all known HAdV receptors, indicating HAdV-D49 uses an unidentified cellular receptor. Conversely, a pseudotyped vector presenting the fiber knob protein of the closely related HAdV-D30 (HAdV-C5/D30K), differing in four amino acids to HAdV-D49, failed to demonstrate the same tropism. These four amino acid changes resulted in a change in isoelectric point of the knob protein, with HAdV-D49K possessing a basic apical region compared to a more acidic region in HAdV-D30K. Structurally and biologically we demonstrate that HAdV-D49 knob protein is unable to engage CD46, whilst potential interaction with CAR is extremely limited by extension of the DG loop. HAdV-C5/49K efficiently transduced cancer cell lines of pancreatic, breast, lung, oesophageal and ovarian origin, indicating it may have potential for oncolytic virotherapy applications, especially for difficult to transduce tumour types. ImportanceAdenoviruses are powerful tools experimentally and clinically. To maximise efficacy, the development of serotypes with low pre-existing levels of immunity in the population is desirable. Consequently, attention has focussed on those derived from species D, which have proven robust vaccine platforms. This widespread usage is despite limited knowledge in their basic biology and cellular tropism. We investigated the tropism of HAdV-D49, demonstrating it uses a novel cell entry mechanism that bypasses all known HAdV receptors. We demonstrate, biologically, that a pseudotyped HAdV-C5/D49K vector efficiently transduces a wide range of cell lines, including those presenting no known adenovirus receptor. Structural investigation suggests that this broad tropism is the result of a highly basic electrostatic surface potential, since a homologous pseudotyped vector with a more acidic surface potential, HAdV-C5/D30K, does not display a similar pan-tropism. Therefore, HAdV-C5/D49K may form a powerful vector for therapeutic applications capable of infecting difficult to transduce cells.

microbiology↗

Single-cell spatial atlas of tertiary lymphoid structures in ovarian cancer

BackgroundRecent advances in highly-multiplexed tissue technologies and image analysis tools have enabled a more detailed investigation of the tumor microenvironment (TME) and its spatial features, including tertiary lymphoid structures (TLSs), at single-cell resolution. TLSs play a major part in antitumor immune responses, however, their role in antitumor immunity in ovarian cancer remains largely unexplored. MethodsIn this study, we generated a comprehensive single-cell spatial atlas of TLSs in ovarian cancer by extracting spatial topology information from in-situ highly-multiplexed cellular imaging using tissue cyclic immunofluorescence (CyCIF). Our analysis included 44 patients with high-grade serous ovarian cancer (HGSC) from the TOPACIO Phase II clinical trial. We combined spatial and phenotypic features from 302,545 single-cells with histopathology, targeted sequencing-based tumor molecular groups, and Nanostring gene expression data. ResultsWe find that TLSs are associated with a distinct TME composition and gene expression profile, characterized by elevated levels of the chemokines CCL19, CCL21, and CXCL13 correlating with the number of TLSs in the tumors. Using single-cell feature quantification and spatial mapping, we uncover enriched germinal center (GC) B cell infiltration and selective spatial attraction to follicular helper T and follicular regulatory T cells in the TLSs from chemo-exposed and BRCA1 mutated HGSCs. Importantly, spatial statistics reveal three main groups of cell-to-cell interactions; significantly enriched structural compartments of CD31+ cells, myeloid, and stromal cell types, homotypic cancer cell- and cancer cell to IBA1+ myeloid cell crosstalk, and enriched selective Tfh, Tfr, and Tfc communities with predominant Tfh - GC B cell interactions. Finally, we report spatiotemporal gradients of GC-B cell interactions during TLS maturation, with enriched non-GC B cell attraction towards the GC B cells in early TLSs, and avoidance patterns with selective GC B-cell communities in the TLSs with GCs. ConclusionsOur single-cell multi-omics analyses of TLSs showed evidence of active adaptive immunity with spatial and phenotypic variations among distinct clinical and molecular subtypes of HGSC. Overall, our findings provide new insights into the spatial biology of TLSs and have the potential to improve immunotherapeutic targeting of ovarian cancer. What is already known on this topicTLSs play a major part in antitumor immune responses, however, their exact role and mechanisms in antitumor immunity are widely unexplored. What this study addsOur results deepen the understanding of TLS biology including cell-cell interactions and shows how the presence of TLSs is characterized with a distinct TME composition and gene expression profile. How this study might affect research, practice or policyOverall, our findings provide new insights into the spatial biology of TLSs and have the potential to improve therapeutic options for ovarian cancer.

cancer biology↗

Perturbational single-cell profiling of patient tumors defines lineage- and context-specific programs of innate immune resistance

AbstractDespite promise in preclinical models, most immuno-oncology drug candidates fail in clinical trials. These failures reflect limitations in our ability to directly model the response of human tumor and immune cells to immunotherapies. To address this gap and test the effect of innate immune agonists, we developed PERCEPT, an approach that uses ex vivo perturbational single-cell RNA sequencing to compare the response of immunomodulatory treatments with unstimulated controls directly in patient samples. Using PERCEPT, we tested cytokines and innate immune agonists in melanoma and Merkel cell carcinoma (MCC) and identified the dsRNA mimetic, RIG-I agonist, Stem Loop RNA (SLR) 14 as a powerful inducer of anti-viral states and enhancer of T cell activation. We compared transcriptional responder and non-responder patient samples and identified midkine (MDK), a multifunctional cytokine, as a potent repressor of IFN signaling in both tumor and immune cells. MDK expression dampened MHC-I presentation in human tumor cells and reduced activation of antigen-presenting cells, disrupting tumor immunity at multiple levels. In contrast to prior studies, we identified MDK as specifically enriched in neuroendocrine cancers such as MCC and small cell lung cancer compared with melanoma, suggesting the importance of lineage- and context-specific targeting. Our results demonstrate the utility of high-dimensional controlled perturbation of patient samples to identify mechanisms of innate immune response and resistance and demonstrate an actionable path towards clinical development of MDK-inhibiting therapies including FDA-approved ALK inhibitors in neuroendocrine cancers.

cancer biology↗

Data Driven Control of Vagus Nerve Stimulation for the Cardiac System

1Vagus nerve stimulation is an emerging therapy that seeks to offset pathological conditions by electrically stimulating the vagus nerve through cuff electrodes, where an electrical pulse is defined by several parameters such as pulse amplitude, pulse width, and pulse frequency. This electroceutical therapy has been approved for epilepsy, and treatment resistant depression. Currently, vagus nerve stimulation is under investigation for the treatment of heart failure, heart arrhythmia, hypertension, and gastric motility disorders. Through several clinical trials that sought to assess vagus nerve stimulation for the treatment of heart failure, stimulation parameters were determined heuristically and the results were left inconclusive, which has led to the suggestion of using a closed-loop approach to optimize the stimulation parameters. A recent investigation has demonstrated highly specific control of cardiac physiology by selectively activating different fibers in the vagus nerve. When multiple locations and multiple stimulation parameters are considered for optimization, the design of closed-loop control becomes considerably more challenging. To address this challenge, we investigated a data-driven control scheme for both modeling and controlling the rat cardiac system. Using an existing in silico physiological model of a rat heart to generate synthetic input-output data, we trained a long short-term memory network (LSTM) to map the effect of stimulation on the heart rate and the blood pressure. The trained LSTM was utilized in a model predictive control framework to optimize the vagus nerve stimulation parameters for set point tracking of the heart rate and the blood pressure in closed-loop simulations. Additionally, we altered the underlying in silico physiological model to consider intra-patient variability, and diseased dynamics from increased sympathetic tone in designing closed-loop VNS strategies. Throughout the different simulation scenarios, we leveraged the design of the controller to demonstrate alternative clinical objectives. Our results show the controller can optimize stimulation parameters to achieve set-point tracking with nominal offset while remaining computationally efficient. Furthermore, we show a controller formulation that compensates for mismatch due to intra-patient variabilty, and diseased dynamics. This study demonstrates the first application and a proof-of-concept for using a purely data-driven approach for the optimization of vagus nerve stimulation parameters in closed-loop control of the cardiac system.

bioengineering↗

Androgen receptor inhibition extends PARP inhibitor activity in prostate cancer models beyond BRCA mutations and defects in homologous recombination repair.

Recent phase 3 clinical trial readouts have shown benefit of the combination of poly(ADP-ribose) polymerase inhibitors (PARPi) with androgen receptor (AR) pathway inhibitors (ARPi) in metastatic, castration-resistant prostate cancer (mCRPC). While benefit was particularly evident in patients with tumours harbouring mutations in homologous recombination repair (HRR) genes, improved outcomes were also observed in patients with no such defined alterations in their cancers. Although there is literature linking AR activity with DNA repair pathways, the basis of the interaction between the AR and PARP is unclear. Here, we show that benefit of the combination of ARPi and PARPi in prostate cancer in vitro and in vivo models with no HRR mutations requires ARPi-responsive cells and a PARPi with PARP1-trapping activity, and does not involve an effect of PARPi treatment in modulating the transcriptional role of the AR. Combination benefit is driven by an increase in DNA damage in the form of DNA double-strand breaks and micronuclei formation, which is not due to a direct control of HRR gene transcription by the AR. In addition, we uncover a novel role of PARP1 in modulating AR recruitment to chromatin in the presence of DNA damage. These data shed new light on the interplay between PARP1 and the AR in dealing with genotoxic insults and provide a mechanism of action consistent with the observed clinical benefit of the combination of PARPi and ARPi in patients with prostate cancer. Statement of significanceCombination of androgen receptor pathway inhibitors and PARP inhibitors has shown efficacy in prostate cancer. We provide a mechanistic explanation through increased DNA damage accumulation observed in combination vs single-agent treatments.

cancer biology↗

The potential of Senicapoc, a KCNN4 inhibitor, for the prevention and treatment of breast cancer

BackgroundGenome-wide association studies have identified a breast cancer risk locus at 19q13.31. The candidate causal variants at this locus are located in the first exon of KCNN4. KCNN4, which regulates membrane potential and Ca2+ signaling, is a good candidate for drug repositioning because its inhibitor, Senicapoc, has been shown to be well tolerated in Phase-II and -III clinical trials for asthma and sickle cell anemia. MethodsWe evaluated public mRNA expression data to determine whether the allele at 19q13.31 associated with increased breast cancer risk was associated with KCNN4 expression. We also used immunohistochemistry to evaluate the relationship between KCNN4 protein expression and breast cancer survival. We then used Senicapoc in two murine mammary tumor models to determine if it would delay tumor development. We also treated mice bearing 4T1 mammary tumors with Senicapoc, by subcutaneous injection and by oral gavage. Finally we used gene editing to make deletions within Kcnn4 in 4T1 to determine whether Senicapoc had off-target effects on tumor growth. ResultsAnalysis of the Genotype-Tissue Expression Project showed that the allele at 19q13.31 associated with increased breast cancer risk is associated with increased KCNN4 expression, suggesting that inhibiting KCNN4 might reduce breast cancer risk. Using immunohistochemistry in a large breast cancer cohort, we found that membrane and cytoplasmic expression is a marker of poor prognosis in triple negative breast cancer. We then tested the efficacy of Senicapoc to prevent and treat breast cancer. This showed that it delays the development of mammary tumors in two murine models, and slows growth of a syngeneic (4T1) model of triple negative breast cancer. Senicapoc monotherapy showed similar efficacy to anthracycline/taxane-based chemotherapy in these studies, with a stronger effect when they were combined. ConclusionsThese results provide a rationale for clinical testing of Senicapoc for treating, and even preventing, breast cancer.

cancer biology↗

Efficient Generation of Expandable Dorsal Forebrain Neural Rosette Stem Cell Lines

Neural stem cells (NSCs) represent an interesting option for developing in vitro disease models and drug screening assays due to their differentiation capacity into neurons and glial cells. Additionally, NSCs are under investigation in on-going clinical trials for treatment of various human neurological disorders. NSCs can be isolated from the central nervous system or derived in vitro from human pluripotent stem cells (hPSCs). However, the current methods for generating NSCs typically include a phase of neural rosette formation and subsequent manual isolation of these tiny structures. As this is a laborious process characterized by operator-dependent variability and scalability challenges, there is a pressing need to develop optimized and scalable protocols to obtain pure NSC populations. In this study, we present a new method for generating highly pure and expandable dorsal forebrain FOXG1+OTX2+TLE4+SOX5+ neural rosette stem cell (NRSC) lines without the necessity for manual isolation of rosette structures. Our findings demonstrate the reproducibility of this protocol through the characterization of different NRSC lines over multiple passages, highlighting the robustness of the process. These NRSCs can be expanded for at least 12 passages without compromising their rosette-formation capacity or their initial dorsal forebrain identity. Furthermore, we show the differentiation capacity of these NRSCs to generate pure populations of TUBB3+ neurons, and under specific conditions, their ability to differentiate into early glial progenitor cells including GFAP+ astrocytes and O4+ oligodendrocytes. Collectively, these results show the capabilities of our protocol to generate an expandable NRSC population suitable for in vitro disease modeling and drug screening, while also suggesting a viable strategy for scalable NRSC production for clinical application.

neuroscience↗

Unlike Chloroquine, mefloquine inhibits SARS-CoV-2 infection in physiologically relevant cells and does not induce viral variants.

Repositioning of clinical approved drugs could represent the fastest way to identify therapeutic options during public health emergencies, the majority of drugs explored for repurposing as antivirals for 2019 coronavirus disease (COVID-19) have failed to demonstrate clinical benefit. Without specific antivirals, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic continues to cause major global mortality. Antimalarial drugs, such as chloroquine (CQ)/hydroxychloroquine (HCQ) and mefloquine have emerged as potential anti-SARS-CoV-2 antivirals. CQ/HCQ entered the Solidarity and RECOVERY clinical trials against COVID-19 and showed lack of efficacy. Importantly, mefloquine is not a 4-aminoquinoline like CQ and HCQ and has been previously repurposed for other respiratory diseases. Unlike the 4-aminoquinolines that accumulate in the high pH of intracellular lysosomes of the lung, the high respiratory tract penetration of mefloquine is driven by its high lipophilicity. While CQ and HCQ exhibit activity in Vero E6 cells, their activity is obviated in TMPRSS2-expressing cells, such as Calu-3 cells, which more accurately recapitulate in vivo entry mechanisms for SARS-CoV-2. Accordingly, here we report the anti-SARS-CoV-2 activity of mefloquine in Calu-3 type II pneumocytes and primary human monocytes. Mefloquine inhibited SARS-CoV-2 replication in Calu-3 cells with low cytotoxicity and EC50 and EC90 values of 1.2 and 5.3 {micro}M, respectively. In addition, mefloquine reduced up to 68% the SARS-CoV-2 RNA levels in infected monocytes, reducing viral-induced inflammation. Mefloquine blocked early steps of the SARS-CoV-2 replicative cycle and was less prone than CQ to induce drug-associated viral mutations and synergized with RNA polymerase inhibitor. The pharmacological parameters of mefloquine are consistent with its plasma exposure in humans and its tissue-to-plasma predicted coefficient points that this drug may accumulate in the lungs. These data indicate that mefloquine could represent an orally available clinically approved drug option against COVID-19 and should not be neglected on the basis of the failure of CQ and HCQ.

microbiology↗

Deletion of Cd248 in Postn positive myofibroblast Fails to Attenuate Cardiac Remodeling and Fibrosis in a Murine Model of Pressure-Overload Cardiomyopathy

BackgroundCardiac fibrosis, driven by activated Periostin (Postn)-expressing myofibroblasts, is a key pathophysiological feature of heart failure induced by pressure overload. The clinic trial tested tumor vascular regulator CD248 has been validated as a potential anti-fibrotic target in ischemic heart injury. We therefore tested the hypothesis that targeting Cd248 specifically in Postn+ myofibroblasts ameliorates pressure-overload cardiomyopathy. MethodsSingle-cell RNA-sequencing data from murine hearts subjected to transverse aortic constriction (TAC) were analyzed to quantify the Cd248+/Postn+ fibroblast population. Subsequently, Postn+ myofibroblast-specific inducible Cd248 knockout mice were subjected to TAC. Gene deletion was induced with tamoxifen from the day of surgery. Cardiac remodeling and function were analyzed 8 weeks after TAC. ResultsAnalysis of scRNAseq data confirmed that about 1/3 of the fibroblasts in the 14-day TAC heart are Cd248+Postn+ fibroblasts. However, comprehensive echocardiographic analysis revealed no significant differences in key parameters of cardiac function or dimensions, including left ventricular ejection fraction, ventricular volumes, wall thickness and global muscle strain between PostnMCM+/-;Cd248fl/fl and PostnMCM+/- controls. Histological analysis at 8 weeks also showed no significant alteration in the extent of interstitial or perivascular fibrosis, myocardial vessel density, or cardiomyocyte hypertrophy. ConclusionThe specific deletion of Cd248 in Postn-expressing myofibroblasts does not mitigate pathological remodeling or fibrosis in response to chronic pressure overload. These findings suggest the role of Cd248 in this cell lineage is not a primary driver of pressure-overload pathology. Therefore, a better understanding of the context-dependent functions of CD248 is critical to successfully guide the clinical translation of CD248-based anti-fibrotic therapies.

pathology↗

Model order reduction for left ventricular mechanics via congruency training

Computational models of the cardiovascular system and heart function are currently being investigated as analytic tools to assist medical practice and clinical trials. Recent technological advances allow for finite element models of heart ventricles and atria to be customized to medical images and to assimilate electrical and hemodynamic measurements. Optimizing model parameters to physiological data is, however, challenging due to the computational complexity of finite element models. Metaheuristic algorithms and other optimization strategies typically require sampling hundreds of points in the model parameter space before converging to optimal solutions. Similarly, resolving uncertainty of model outputs to input assumptions is difficult for finite element models due to their computational cost. In this paper, we present a novel, multifidelity strategy for model order reduction of 3-D finite element models of ventricular mechanics. Our approach is centered around well established findings on the similarity between contraction of an isolated muscle and the whole ventricle. Specifically, we demonstrate that simple linear transformations between sarcomere strain (tension) and ventricular volume (pressure) are sufficient to reproduce global pressure-volume outputs of 3-D finite element models even by a reduced model with just a single myocyte unit. We further develop a procedure for congruency training of a surrogate low-order model from multi-scale finite elements, and we construct an example of parameter optimization based on medical images. We discuss how the presented approach might be employed to process large datasets of medical images as well as databases of echocardiographic reports, paving the way towards application of heart mechanics models in the clinical practice.

biophysics↗