Biology subjects

Verma, R.

Publications and source records attributed to Verma, R..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Harmonization of Structural Brain Networks for Multi-site Studies

Diffusion MRI-based structural connectomes are increasingly used to investigate brain connectivity changes associated with various disorders. However, small sample sizes in individual studies, along with highly heterogeneous disorder-related manifestations, underscore the need to pool datasets across multiple studies to be able to identify coherent and generalizable connectivity patterns linked to these disorders. Yet, combining datasets introduces site-related differences due to variations in scanner hardware or acquisition protocols. These differences highlight the necessity for statistical data harmonization to mitigate site-related effects on structural connectomes while preserving the biological information associated with participant demographics and the disorders. While several paradigms exist for harmonizing normally distributed neuroimaging measures, this paper represents the first effort to establish a harmonization framework specifically tailored for the structural connectome. We conduct a thorough investigation of various statistical harmonization methods, adapting them to accommodate the unique distributional characteristics and graph-based properties of structural connectomes. Through rigorous evaluation, we demonstrate that the generalized linear model with a log-linked gamma model (gamma-GLM) outperforms other approaches in modeling structural connectomes, enabling the effective removal of site-related biases in both edge-based and downstream graph analyses while preserving biological variability. Two real-world applications further highlight the utility of our harmonization framework in addressing challenges in multi-site structural connectome analysis. Specifically, harmonization with gamma-GLM enhances the generalizability of connectome-based machine learning predictors to new datasets and increases statistical power for detecting group-level differences. Our work provides essential guidelines for harmonizing multi-site structural connectomes, paving the way for more robust discoveries through collaborative research in the era of team science and big data.

neuroscience↗

bioRxiv2024

Network controllability analysis reveals the antiviral potential of Etravirine against Hepatitis E Virus infection

Hepatitis E virus (HEV) is a major cause of acute viral hepatitis in lower- and middle-income countries. HEV infection may lead to acute liver failure, chronic liver disease and high mortality in pregnant women. Antiviral therapy is not a standard treatment for HEV patients. Computational biology tools promise to revolutionize the antiviral drug discovery. Here, we analyzed the transcriptome data of HEV infected primary human hepatocyte (PHH)-cells through connectivity map database and applied control theory on functional network to identify antiviral targets against HEV. The above analyses predicted PKC{beta}, PKB/AKT and CK1{varepsilon} as potential antiviral targets against HEV. The antiviral function of PKB/AKT and CK1{varepsilon} was experimentally validated by using respective biochemical inhibitors in g3 (genotype 3)-HEV replicon and Huh7 cell-based model of g3 and g1-HEV infection. Further, knockdown of CK1{varepsilon} showed a similar effect. These data confirmed that CK1{varepsilon} is an antiviral target for HEV. At present, there are no FDA approved drugs targeting CK1{varepsilon}. Etravirine is an FDA approved non-nucleoside reverse transcriptase inhibitor drug, used for the treatment of Human immunodeficiency virus type 1 (HIV-1) infected patients. An in silico study predicted Etravirine to be a potent inhibitor of CK1{varepsilon}. Our experiments revealed potent antiviral activity of Etravirine against HEV, which was mediated via its ability to inhibit the activity of CK1{varepsilon}. Taken together, the current study demonstrates that PKB/AKT and CK1{varepsilon} are bonafide antiviral targets for HEV and paves the way for repurposing Etravirine for the treatment of HEV infected patients. ImportanceAntiviral treatment is not the standard care for acute viral hepatitis E patients. Unbiased identification of antiviral targets or large-scale screening of antiviral compounds against the hepatitis E virus (HEV) has not been reported. Here, computational biology approach was followed to unbiasedly identify antiviral targets of HEV. Transcriptome data of HEV infected primary human hepatocyte (PHH) cells were analyzed to identify modulators of the network and generate directional networks. Network controllability analysis identified PKC{beta}, PKB/AKT and CK1{varepsilon} as potential antiviral targets against HEV. Antiviral function of PKB/AKT and CK1{varepsilon} was confirmed using cell-based models of genotype 1 (g1)- and g3-HEV infection. Further experiments demonstrated the antiviral activity of Etravirine against HEV, mediated via its ability to inhibit the CK1{varepsilon} activity. Etravirine is an FDA approved non-nucleoside reverse transcriptase inhibitor, used for the treatment of Human immunodeficiency virus type-1 (HIV-1)-infected patients. This study reveals the potential of repurposing Etravirine for treatment of HEV patients and illustrate the importance of computational biology in antiviral drug discovery.

microbiology↗

bioRxiv2024

TFIIS is required for reproductive development and thermal adaptation in barley

Regulation of transcriptional machinery and its adaptive role under different stress conditions are studied extensively in the dicot model plant Arabidopsis, but our knowledge on monocot species remains elusive. TFIIS is an RNA polymerase II associated transcription elongation co-factor. Previously it was shown that TFIIS ensures efficient transcription elongation that is necessary for heat stress survival in A. thaliana. However, the function of TFIIS has not been analysed in monocots. In the present work, we have generated and studied independent tfIIscrispr mutant barley lines. We show that, TFIIS is needed for reproductive development and heat stress survival in barley. The molecular basis of HS-sensitivity of tfIIs mutants is the retarded expression of heat stress protein transcripts, that leads to late accumulation of HSP chaperones, enhanced proteotoxicity and ultimately to lethality. We also show that TFIIS is induced and autoregulated in response to heat, supporting a conserved adaptive function of these control elements for plant thermal adaptation. In sum, our results are a step forward for the better understanding of transcriptional machinery regulation in monocot crops.

plant biology↗

bioRxiv2024

Bridging fungal resistance and plant growth through constitutive overexpression of Thchit42 gene in Pelargonium graveolens

Pelargonium graveolens essential oil possesses significant attributes, known for perfumery and aromatherapy. However, optimal yield and propagation are predominantly hindered by biotic stress. All biotechnological approaches have yet to prove effective in addressing fungal resistance. The current study developed transgenic geranium bridging molecular mechanism of fungal resistance and plant growth by introducing cassette 35S::Thchit42. Furthermore, 120 independently putative transformed explants were regenerated on kanamycin fortified medium. Primarily transgenic lines were demonstrated peak pathogenicity and antifungal activity against formidable Colletotrichum gloeosporioides and Fusarium oxysporum. Additionally, phenotypic analysis revealed [~]2fold increase in leaf size and [~]2.1fold enhanced oil content. To elucidate the molecular mechanisms for genotypic cause, De novo transcriptional profiles were analyzed to indicate that the auxin-regulated longifolia gene is accountable for augmentation in leaf size, and ZF RICESLEEPER attributes growth upregulation. Collectively, data provides valuable insights into unravelling the mechanism of Thchit42-mediated crosstalk between morphological and chemical alteration in transgenic plants. This knowledge might create novel opportunities to cultivate fungal-resistant geranium throughout all seasons to fulfil demand.

plant biology↗

bioRxiv2023

Modulation of hepatic transcription factor EB activity during cold exposure uncovers direct regulation of bis(monoacylglycerol)phosphate lipids by Pla2g15

Cold exposure is a selective environmental stress that elicits a rapid metabolic shift to maintain energy homeostasis. In response to cold exposure, the liver rewires the metabolic state shifting from glucose to lipid catabolism. By probing the liver lipids in cold exposure, we observed that the lysosomal bis(monoacylglycero)phosphate (BMP) lipids were rapidly increased during cold exposure. BMP lipid changes occurred independently of lysosomal abundance but were dependent on the lysosomal transcriptional regulator transcription factor EB (TFEB). Knockdown of TFEB in hepatocytes decreased BMP lipid levels and led to cold intolerance in mice. We assessed TFEB binding sites of lysosomal genes and determined that the phospholipase Pla2g15 regulates BMP lipid catabolism. Knockdown of Pla2g15 in mice increased BMP lipid levels, ablated the cold-induced rise, and improved cold tolerance. Knockout of Pla2g15 in mice and hepatocytes led to increased BMP lipid levels, that were decreased with re-expression of Pla2g15. Mutation of the catalytic site of Pla2g15 ablated the BMP lipid breakdown. Together, our studies uncover TFEB regulation of BMP lipids through Pla2g15 catabolism.

biochemistry↗

bioRxiv2023

The fatty liver disease-causing protein PNPLA3-I148M alters lipid droplet-Golgi dynamics

Non-alcoholic fatty liver disease (NAFLD), recently renamed metabolic dysfunction-associated steatotic liver disease (MASLD), is a progressive metabolic disorder that begins with aberrant triglyceride accumulation in the liver and can lead to cirrhosis and cancer. A common variant in the gene PNPLA3, encoding the protein PNPLA3-I148M, is the strongest known genetic risk factor for MASLD to date. Despite its discovery twenty years ago, the function of PNPLA3, and now the role of PNPLA3-I148M, remain unclear. In this study, we sought to dissect the biogenesis of PNPLA3 and PNPLA3-I148M and characterize changes induced by endogenous expression of the disease-causing variant. Contrary to bioinformatic predictions and prior studies with overexpressed proteins, we demonstrate here that PNPLA3 and PNPLA3-I148M are not endoplasmic reticulum-resident transmembrane proteins. To identify their intracellular associations, we generated a paired set of isogenic human hepatoma cells expressing PNPLA3 and PNPLA3-I148M at endogenous levels. Both proteins were enriched in lipid droplet, Golgi, and endosomal fractions. Purified PNPLA3 and PNPLA3-I148M proteins associated with phosphoinositides commonly found in these compartments. Despite a similar fractionation pattern as the wild-type variant, PNPLA3-I148M induced morphological changes in the Golgi apparatus, including increased lipid droplet-Golgi contact sites, which were also observed in I148M-expressing primary human patient hepatocytes. In addition to lipid droplet accumulation, PNPLA3-I148M expression caused significant proteomic and transcriptomic changes that resembled all stages of liver disease. Cumulatively, we validate an endogenous human cellular system for investigating PNPLA3-I148M biology and identify the Golgi apparatus as a central hub of PNPLA3-I148M-driven cellular change. Significance StatementFatty liver disease affects nearly a quarter of the worlds population and has both environmental and genetic risk factors. A mutation in the gene PNPLA3 that converts Ile 148 to Met is the strongest known genetic risk factor for developing fatty liver disease. Using a series of techniques to track endogenous PNPLA3 and PNPLA3-I148M biogenesis and localization, we reveal new insights into how the mutation changes cellular dynamics. Although previous reports focus on its role on lipid droplets, we reveal that PNPLA3-I148M also functions at the Golgi apparatus, an organelle critical for protein transport into and out of the cell and lipid signaling. PNPLA3-I148M causes altered Golgi morphology and drives changes reminiscent of liver disease.

cell biology↗

bioRxiv2023

The Implant-Induced Foreign Body Response is Limited by CD13-Dependent Regulation of Ubiquitination of Fusogenic Proteins

Implanted medical devices from artificial heart valves, arthroscopic joints to implantable sensors often induce a Foreign Body Response (FBR), a form of chronic inflammation resulting from the inflammatory reaction to a persistent foreign stimulus. The FBR is characterized by a subset of multinucleated giant cells (MGCs) formed by macrophage fusion, the Foreign Body Giant cells (FBGCs), accompanied by inflammatory cytokines, matrix deposition and eventually, deleterious fibrotic implant encapsulation. Despite efforts to improve biocompatibility, implant-induced FBR persists, compromising the utility of devices and making efforts to control the FBR imperative for long-term function. Controlling macrophage fusion in FBGC formation presents a logical target to prevent implant failure, but the actual contribution of FBGCs to FBR-induced damage is controversial. CD13 is a molecular scaffold and in vitro induction of CD13KO bone-marrow progenitors generates many more MGCs than WT, suggesting CD13 regulates macrophage fusion. Moreover, in the mesh implant model of FBR, CD13KO mice produced significantly more peri-implant FBGCs with enhanced TGF{beta} expression and increased collagen deposition vs. WT. Pre-fusion, increased protrusion and microprojection formation accompanies hyperfusion in the absence of CD13. Expression of fusogenic proteins driving cell-cell fusion was aberrantly sustained at high levels in CD13KO MGCs, which we show is due to a novel CD13 function, regulating ubiquitin/proteasomal protein degradation. By controlling protein degradation, CD13 becomes a physiologic brake preventing aberrant macrophage fusion and may be a novel therapeutic target to improve success of implanted medical devices. Furthermore, our data directly implicates FBGCs in the detrimental fibrosis that characterizes the FBR.

cell biology↗

bioRxiv2023

CrOssing fiber Modeling in the Peritumoral Area using dMRI (COMPARI)

Visualization of fiber tracts around the tumor is critical for neurosurgical planning and preservation of crucial structural connectivity during tumor resection. Biophysical modeling approaches estimate fiber tract orientations from differential water diffusivity information of diffusion MRI. However, the presence of edema and tumor infiltration presents a challenge to visualize crossing fiber tracts in the peritumoral region. Previous approaches proposed free water modeling to compensate for the effect of water diffusivity in edema, but those methods were limited in estimating complex crossing fiber tracts. We propose a new cascaded multi-compartment model to estimate tissue microstructure in the presence of edema and pathological contaminants in the area surrounding brain tumors. In our model (COMPARI), the isotropic components of diffusion signal, including free water and hindered water, were eliminated, and the fiber orientation distribution (FOD) of the remaining signal was estimated. In simulated data, COMPARI accurately recovered fiber orientations in the presence of extracellular water. In a dataset of 23 patients with highly edematous brain tumors, the amplitudes of FOD and anisotropic index distribution within the peritumoral region were higher with COMPARI than with a recently proposed multi-compartment constrained deconvolution model. In a selected patient with metastatic brain tumor, we demonstrated COMPARIs ability to effectively model and eliminate water from the peritumoral region. The white matter bundles reconstructed with our model were qualitatively improved compared to those of other models, and allowed the identification of crossing fibers. In conclusion, the removal of isotropic components as proposed with COMPARI improved the bio-physical modeling of dMRI in edema, thus providing information on crossing fibers, thereby enabling improved tractography in a highly edematous brain tumor. This model may improve surgical planning tools to help achieve maximal safe resection of brain tumors.

bioengineering↗

bioRxiv2022

Choice of parcellation atlas might not be too critical for connectomic analysis

Connectomics has been a rapidly growing discipline in neuroimaging and neuroscience that evolved our understanding of the brain. Connectomics involves representing the brain as a network of regions, where the parcellation of the brain into regions using a template atlas is an integral part of the analysis. Over developmental and young adult cohorts of healthy individuals, we investigated how choosing parcellation atlases at certain resolutions affect sex classification and age prediction tasks performed using deep learning on structural connectomes. Datasets were processed on a total of 35 parcellations, where the only significant difference was observed for age prediction on the developmental cohort with a slight improvement on higher resolutions. This indicates that choice of parcellation scheme is generally not critical for deep learningbased age prediction and sex classification. Therefore, results between studies using different parcellation schemes could be comparable and repeating analyses on multiple atlases might be unnecessary.

neuroscience↗

bioRxiv2022

Analysis of structural network topology alterations in autism and its relationship with autism severity

Autism Spectrum Disorder (ASD) is a public health concern ranging along a continuum of severity. The neurobiological motives behind ASD have been widely explored with reports about aberrant brain anatomy and functional connectivity. However, research on the underlying structural connectivity alterations is limited. We propose the application of a novel connectomic measure called Network Normality Score (NNS) to identify brain abnormalities and quantity topological dissimilarities in individuals with ASD. We show that the network topology of structural connectivity is altered in ASD brains relative to healthy controls at the global and system levels. We demonstrate that structural connectivity differences are more pronounced in certain subnetworks. Finally, we quantify the association between network similarity and behavioral autism severity to show the efficacy of NNS as a neuroimaging measure.

neuroscience↗

bioRxiv2022

A chromosome-scale assembly of Brassica carinata (BBCC) accession HC20 containing resistance to multiple pathogens and an early generation assessment of introgressions into B. juncea (AABB)

Brassica carinata (BBCC) commonly referred to as Ethiopian mustard is a natural allotetraploid containing the genomes of Brassica nigra (BB) and Brassica oleracea (CC). It is an oilseed crop endemic to the Northeastern regions of Africa. Although it is grown in a limited manner, B. carinata is of value as it is resistant/highly tolerant to most of the pathogens affecting cultivated Brassica species of the Us triangle that are grown worldwide as oilseed and vegetable crops. We report a chromosome-scale genome assembly of B. carinata accession HC20 using long-read Oxford Nanopore and Illumina sequencing and BioNano optical maps. The assembly has a scaffold N50 of ~39.8 Mb and covers ~1.11 Gb of the genome. We compared the available long-read genome assemblies of the six species of the Us triangle and found a highly conserved gene number and collinearity suggesting that B. juncea (AABB), B. napus (AACC), and B. carinata are strict allopolyploids. We cataloged the nucleotide-binding and leucine-rich repeat immune receptor (NLR) repertoire of B. carinata resulting in the identification of 465 NLRs. We investigated the extent and nature of early generation genomic interactions between the subgenomes of B. carinata and B. juncea in interspecific crosses between the two species. We found that C chromosome additions are well tolerated, with homoeologous exchanges occurring between the A and C genomes. Based on the genomic interactions, we propose strategies to utilize the interspecific crosses for transferring disease resistance from B. carinata to B. juncea and other Brassica species.

plant biology↗

bioRxiv2022

Human endogenous retrovirus-R envelope is a host restriction factor against severe acute respiratory syndrome-coronavirus-2

Coronavirus induced disease-19 (COVID-19), caused by the SARS-CoV-2 remains a major global health challenge. Human endogenous retroviruses (HERVs) represent retroviral elements that got integrated into the ancestral human genome. HERVs are important in development and diseases, including cancer, inflammation and viral infections. Here, we analyzed the expression of several HERVs in SARS-CoV-2 infected cells and observed increased activity of HERV-E, HERV-V, HERV-FRD, HERV-MER34, HERV-W and HERV-KHML2. In contrast, HERV-R-envelope was downregulated in cell-based models and COVID-19 patient PBMCs. HERV-R overexpression inhibited SARS-CoV-2 replication, suggesting its antiviral action. Further studies demonstrated the role of extracellular signal-regulated kinase (ERK) in regulating HERV-R antiviral activity. Cross-talk between the ERK and p38 MAPK controls HERV-R envelope synthesis, which in turn modulates the replication of SARS-CoV-2. These findings establish the importance of HERV-R envelope as a host restriction factor against SARS-CoV-2 and illustrate the advantage of integration and evolutionary maintenance of retroviral-elements in the human genome.

microbiology↗

bioRxiv2022

MAP1LC3C regulates lysosomal exocytosis and induces zinc reprogramming in renal cancer cells

MAP1LC3C (LC3C) is a member of the microtubule associated family of proteins that are essential in the formation of autophagosomes and lysosomal degradation of cargo. LC3C has tumor suppressing activity and its expression is dependent on kidney cancer tumor suppressors, such as VHL and FLCN. Recently we demonstrated that LC3C autophagy is regulated by noncannonical upstream regulatory complexes and targets for degradation postdivision midbody rings associated with cancer cells stemness. Here we show that loss of LC3C leads to peripheral positioning of the lysosomes and lysosomal exocytosis (LE) in a subset of cells. This process is independent of the autophagic activity of LC3C. Analysis of isogenic cells with low and high LE shows substantial transcriptomic reprogramming with altered expression of Zn-related genes and activity of Polycomb Repressor Complex 2 (PRC2), accompanied by a robust decrease in intracellular Zn. Metabolomic analysis revealed alterations in amino acid steady-state levels. Cells with augmented LE show tumor initiation properties and form aggressive tumors in xenograft models. Immunocytochemistry identified high levels of LAMP1 on the plasma membrane of cancer cells in human ccRCC and reduced levels of Zn, an indication that LE is a frequent event in ccRCC, potentially contributing to the loss of Zn. Overall, these data indicate that an important tumor suppressing activity of LC3C is contributing to the reprogramming of lysosomal activity and Zn metabolism with implication for epigenetic remodeling in a subpopulation of tumor propagating properties of cancer cells.

cell biology↗

bioRxiv2022

RNA-protein interactome at the Hepatitis E virus internal ribosome entry site

Multiple processes exist in a cell to ensure continuous production of essential proteins either through cap-dependent or cap-independent translation processes. Viruses depend on the host translation machinery for viral protein synthesis. Therefore, viruses have evolved clever strategies to utilize the host translation machinery. Earlier studies have shown that genotype 1-Hepatitis E virus (g1-HEV) utilizes both cap-dependent and cap-independent translation machineries for its replication and proliferation. Cap-independent translation in g1-HEV is driven by an eighty seven nucleotide-long RNA element which acts as a noncanonical, internal ribosome entry site like (IRESl) element. Here, we have identified the RNA-protein interactome of the HEV IRESl element and characterized the functional significance of some of its components. Our study reveals indispensable roles of host ribosomal protein RPL5 and DHX9 (RNA helicase A) in mediating efficient translation from the IRESl element and establish the function of HEV IRESl as a bonafide internal ribosome entry site. Author summaryProtein synthesis is a fundamental process for survival and proliferation of all living organisms. Majority of cellular proteins are produced through cap-dependent translation. Cells also utilize a variety of cap-independent translation processes to synthesize essential proteins during stress. Viruses depend on the host cell translation machinery to synthesize their own proteins. Hepatitis E virus is a major cause of hepatitis worldwide. The viral genome is a capped positive strand RNA. Viral non-structural and structural proteins are synthesized through a cap-dependent translation process. An earlier study from our laboratory reported the presence of a fourth ORF in genotype 1-HEV, which produced the ORF4 protein using a cap-independent internal ribosome entry site-like (IRESl) element. In the current study, we identified the host proteins that associate with the HEV-IRESl RNA and generated the RNA-protein interactome. Through a variety of experimental approaches, our data proves that HEV-IRESl is a bonafide internal ribosome entry site.

microbiology↗

bioRxiv2021

SARS-CoV-2 infects human adipose tissue and elicits an inflammatory response consistent with severe COVID-19

The COVID-19 pandemic, caused by the viral pathogen SARS-CoV-2, has taken the lives of millions of individuals around the world. Obesity is associated with adverse COVID-19 outcomes, but the underlying mechanism is unknown. In this report, we demonstrate that human adipose tissue from multiple depots is permissive to SARS-CoV-2 infection and that infection elicits an inflammatory response, including the secretion of known inflammatory mediators of severe COVID-19. We identify two cellular targets of SARS-CoV-2 infection in adipose tissue: mature adipocytes and adipose tissue macrophages. Adipose tissue macrophage infection is largely restricted to a highly inflammatory subpopulation of macrophages, present at baseline, that is further activated in response to SARS-CoV-2 infection. Preadipocytes, while not infected, adopt a proinflammatory phenotype. We further demonstrate that SARS-CoV-2 RNA is detectable in adipocytes in COVID-19 autopsy cases and is associated with an inflammatory infiltrate. Collectively, our findings indicate that adipose tissue supports SARS-CoV-2 infection and pathogenic inflammation and may explain the link between obesity and severe COVID-19. One sentence summaryOur work provides the first in vivo evidence of SARS-CoV-2 infection in human adipose tissue and describes the associated inflammation.

immunology↗

bioRxiv2021

A Systematic Interrogation of MHC Class I Antigen Presentation Identifies Constitutive and Compensatory Protein Degradation Pathways

The adaptive immune system distinguishes self from non-self by surveying peptides generated from degradation of intracellular proteins that are loaded onto MHC Class I molecules for display on the cell surface. While early studies reported that the bulk of cell surface MHC Class I complexes require the ubiquitin-proteasome system (UPS) for their generation, this conclusion has been challenged. To better understand MHC Class I peptide origins, we sought to carry out a comprehensive, quantitative census of the MHC Class I peptide repertoire in the presence and absence of UPS activity. We introduce optimized methodology to enrich for authentic Class I-bound peptides in silico and then quantify by mass spectrometry their relative amounts upon perturbation of the ubiquitin-proteasome system. Whereas most peptides are dependent on the proteasome and ubiquitination for their generation, a surprising 30% of the MHC Class I repertoire, enriched in peptides of mitochondrial origin, appears independent of these pathways. A further [~]10% of Class I-bound peptides were found to be dependent on the proteasome but independent of ubiquitination for their generation. Notably, clinically achievable partial inhibition of the proteasome resulted in display of novel peptides antigens, at least one of which promotes immune system activation. Our results suggest that generation of MHC Class I*peptide complexes is more complex than previously recognized and also provide evidence for compensatory peptide-generating pathways when canonical pathways are impaired.

molecular biology↗

bioRxiv2021

Targeting of Cdc42 GTPase in regulatory T cells unleashes anti-tumor T cell immunity

Regulatory T (Treg) cells play an important role in maintaining immune tolerance through inhibiting effector T cell function. In the tumor microenvironment, Treg cells are utilized by tumor cells to counteract effector T cell-mediated tumor killing. Targeting Treg cells may thus unleash the anti-tumor activity of effector T cells. While systemic depletion of Treg cells can cause excessive effector T cell responses and subsequent autoimmune diseases, controlled targeting of Treg cells may benefit cancer patients. Here we show that Treg cell-specific heterozygous deletion or pharmacological targeting of Cdc42 GTPase does not affect Treg cell numbers but induces Treg cell plasticity, leading to anti-tumor T cell immunity without detectable autoimmune reactions. Cdc42 targeting potentiates an immune checkpoint blocker anti-PD-1 antibody-mediated T cell response against mouse and human tumors. Mechanistically, Cdc42 targeting induces Treg cell plasticity and unleashes antitumor T cell immunity through carbonic anhydrase I-mediated pH changes. Thus, rational targeting of Cdc42 in Treg cells holds therapeutic promises in cancer immunotherapy. SignificanceEffector T lymphocytes promote autoimmune diseases but have potential to kill tumor cells. However, cancer cells can evade T cell-mediated killing in part by utilizing regulatory T (Treg) cells to inhibit effector T cell function. Here we show that Treg cell-specific heterozygous deletion of Cdc42 gene that encodes Cdc42 GTPase dampens Treg cell fitness through carbonic anhydrase I-mediated pH changes, leading to anti-tumor T cell immunity. Pharmacological targeting of Cdc42 mimics genetic deletion of Cdc42 in impairing Treg cell fitness and evoking anti-tumor T cell immunity. Importantly, Cdc42 targeting does not appear to cause systemic autoimmunity. Given that current cancer immunotherapies only demonstrate limited clinical efficacies, our findings may open a new avenue for cancer immunotherapy.

immunology↗

bioRxiv2021

A Novel Model for Encephalomyosynangiosis Surgery after Middle Cerebral Artery Occlusion-Induced Stroke in Mice

Background and PurposeNo effective treatment is available for most patients who suffer ischemic stroke. Development of novel treatment options is imperative. The brain attempts to self-heal after ischemic stroke via various mechanism mediated by restored blood circulation in affected region of brain but this process is limited by inadequate angiogenesis or neoangiogenesis. Encephalomyosynangiosis (EMS) is a neurosurgical procedure that achieves angiogenesis with low morbidity in patients with moyamoya disease, reducing risk of stroke. However, EMS, surgery has never been studied as an therapeutic option after ischemic stroke. Here we described a novel procedure and feasibility data for EMS after ischemic stroke in mice. MethodsA 60 mins of middle cerebral artery occlusion (MCAo) was used to induce ischemic stroke in mice. After 3-4 hours of MCAo onset/sham, EMS was performed. Mortality of EMS, MCAo and. MCAo+EMS mice was recorded up to 21 days after surgery. Graft tissue viability was measured using a nicotinamide adenine dinucleotide reduced tetrazolium reductase assay. ResultsEMS surgery after ischemic stroke does not increase mortality compared to stroke alone. Graft muscle tissue remained viable 21 days after surgery. ConclusionsThis novel protocol is effective and well-tolerated, may serve as novel platform for new angiogenesis and thus recovery after ischemic stroke. If successful in mice, EMS can a very feasible and novel treatment option for ischemic stroke in humans.

neuroscience↗