bioRxiv Science⌕ Search

Biology subjects

Pathak, S.

Publications and source records attributed to Pathak, S..

At least 19 recordsLinked to original sources

Mesaconic acid delivery via biomaterials and engineered probiotics to the gut reduces inflammation in Crohn's Diseases mouse models

Mesaconate (MES, an immunosuppressive metabolite) but not itaconate is upregulated in stool of Crohns Disease (CD) patients, albeit below therapeutic levels.. However, colonic MES level is difficult to maintain because of its high absorption rate, limiting its therapeutic potential for CD. Herein, we developed two strategies that elevate MES level and suppress inflammation: EcN-CAD, an engineered probiotic Escherichia coli Nissle 1917 (EcN) that overexpresses cis-aconitate decarboxylase (CAD, produces itaconic acid that is converted to MES); and MES+Zn, a Zinc-MES ionically crosslinked formulation. Mechanistically, MES modulates T cell function by downregulating glycolytic and mitochondrial activity and decrease ROR{gamma}t expression. In preclinical SAMP1/YitFC dexamethasone-withdrawal model and TNFDARE model, MES+Zn decreased gut permeability significantly compared to controls and reduced myeloperoxidase (MPO, an inflammatory marker) 1000-fold compared to controls. EcN-CAD probiotics decreased ROR{gamma}t expression in CD4+ and CD8+ T cells, gut permeability and inflammation in preventive SAMP1/YitFC model, and SAMP1/YitFC dexamethasone-withdrawal model. Overall, MES rewires T cell responses and technologies that enhance MES levels can be effective in gut-related inflammatory diseases.

immunology↗

A Charge-Encoded Rheostat Permits Helix Nucleation but Limits Propagation in Skp1

Molecular recognition by intrinsically disordered regions (IDRs) is widely thought to involve coupled folding and binding, yet the sequence features that regulate this transition remain underexplored. Here we show that helix 8 (H8), a disordered C-terminal segment of the SCF ubiquitin ligase adaptor Skp1, is intrinsically prevented from forming a stable helix by its own sequence grammar. Using an integrative approach to dissect its conformational dynamics, we find that H8 frequently nucleates helical structure but rarely propagates into a fully formed stable helix, populating instead a shallow metastable basin of helical intermediates. Contrary to conventional models of helix-coil exchange, where nucleation is rate limiting, helix initiation in H8 is readily accessible, while propagation is selectively suppressed by a glutamate-rich acidic patch. This acidic segment acts as a charge-sensitive conformational rheostat that limits helix extension and maintains H8 in a predominantly disordered state. As a result, H8 transiently samples partially helical conformations on the microsecond timescale without committing to a stable fold. We propose that this propagation-limited mechanism preserves conformational flexibility while maintaining recognition competence across a structurally diverse family of F-box binding partners. More broadly, our findings suggest that charged- hydrophobic-charged sequence patterning can encode conditional, context-dependent structure as a general organisational principle in intrinsically disordered proteomes.

biophysics↗

Aligned basement membrane-modified collagen scaffolds for skeletal muscle tissue engineering

Biomaterial scaffolds for repairing traumatic muscle injuries require restoration of both the anisotropic architecture and basement membrane extracellular matrix cues critical to normal muscle function. To address this need, we establish a collagen-glycosaminoglycan (CG) scaffold platform pairing an aligned pore microstructure, produced via directional freeze-drying, with basement membrane protein functionalization via carbodiimide crosslinking. Laminin and/or collagen IV are successfully tethered and retained within CG scaffolds over 7 days without significantly altering pore size or alignment, confirming stable protein functionalization and preservation of scaffold architecture. Human muscle progenitor cells show excellent viability and metabolic activity in all scaffold groups, with collagen IV functionalization significantly enhancing myotube number and fusion index. Toward establishing scaffold compatibility with non-myogenic support cells, we show that neural stem cells remain viable and metabolically active across all scaffold conditions. Overall, these findings highlight the combination of aligned scaffold architecture and collagen IV functionalization as potentially impactful for skeletal muscle tissue engineering.

bioengineering↗

Targeted depletion of CD38+ autoreactive T cells prevents type 1 diabetes

Type 1 diabetes (T1D) is caused by T cell-mediated autoimmune destruction of insulin-producing islet {beta}-cells. Treatment with T-cell depleting therapies delays the progression of stage 2 and 3 T1D, but these agents exert broad immunosuppressive effects on T cell populations, including T regulatory cells (Tregs), which are key in promoting immune tolerance. We evaluated non-obese diabetic (NOD) mice and recently diagnosed T1D patients and identified CD38 as a marker for pathogenic T cell populations. Using adoptive T-cell transfer in Recombination Activating Gene 1 knockout NOD mice and in a humanized mouse model of autoimmune diabetes, we demonstrated that CD38-expressing autoreactive T cells drive diabetes pathogenesis. Furthermore, we found that selective depletion of CD38+ cells, using an anti-CD38 monoclonal antibody (mAb), prevents insulitis and diabetes onset without depleting CD4+CD25+ Tregs. Administration of anti-CD38 mAb did not adversely affect islet function and may selectively eliminate immunogenic senescent islet {beta}-cells. These results support the strategy of selectively depleting diabetogenic T cells using an anti-CD38 mAb to treat T1D and restore immune tolerance. Therefore, transient depletion of autoreactive T cells using anti-CD38 mAb may provide a novel strategy to prevent or abrogate {beta}-cell autoimmunity in T1D. One sentence summaryPathogenic autoreactive are characterized by CD38 overexpression, and their selective depletion with anti-CD38 monoclonal antibody prevents autoimmune diabetes.

immunology↗

Optical flow reveals motility signatures for inferring pathogenic bacterial mixture compositions via temporal convolutional networks

With the rapid expansion of global food demand, aquaculture has become a critical pillar for future food security. However, aquaculture systems remain highly vulnerable to pathogenic bacteria, and rapid identification of antagonistic microbes is essential for sustainable disease control. Conventional evaluation approaches rely on fluorescence labeling or post-culture assays, limiting the ability to quantify dynamic interactions in mixed microbial populations in a real-time and label-free manner. Here, we propose a computational framework for classifying the mixing ratio of Vibrio harveyi and environmental bacteria using time-series motion features extracted from microscopy videos. We defined 24 interpretable motility descriptors and employed a Temporal Convolutional Network (TCN) to learn their temporal structure. The proposed method achieved a classification accuracy of 93.3%, outperforming conventional static statistical approaches and alternative machine learning models. These findings indicate that mixture discrimination in microbial communities is governed not by absolute motility magnitude, but by collective alignment and its temporal stability. Our study establishes a time-resolved computational framework for quantifying dynamic collective order in mixed microbial populations and highlights its potential for label-free automated screening and robotic microbiological applications. Author summaryBacterial infections pose a major threat to aquaculture, and rapid identification of antagonistic microbes is essential for sustainable disease management. Existing screening approaches often require fluorescent labeling or post-culture analysis, making real-time evaluation of mixed bacterial populations difficult. In this study, we show that mixture ratios of Vibrio harveyi and environmental bacteria can be accurately classified from time-series motion features extracted from microscopy videos. By applying TCN to 24 interpretable motility descriptors, we achieved high classification accuracy without relying on fluorescent markers. Our analysis demonstrates that collective directional alignment and its temporal stability, rather than absolute swimming speed, are the key determinants of mixture discrimination. This work introduces a computational strategy for quantifying dynamic collective order in microbial communities and supports the development of label-free, automated screening platforms for microbiological applications.

microbiology↗

Donor-derived CD8+CD122+ Tregs generated in mixed donor chimeric NOD mice delete autoreactive T cells

The establishment of mixed hematopoietic chimerism is a promising way to induce immune tolerance for islet replacement therapy and to treat the underlying autoimmunity in type 1 diabetes (T1D). Mixed chimerism not only promotes effective thymic negative selection of autoreactive cells but also restores regulatory T cell (Treg) function and peripheral tolerance. In the current study, we determined that a novel class of donor-derived CD8+CD44+CD122+ Tregs (d-CD8+CD122+ Tregs) plays a crucial role in controlling autoimmunity in non-obese diabetic (NOD) mice with induced mixed chimerism. Using adoptive T cell transfer experiments, we showed that d-CD8+CD122+ Tregs abrogate autoimmunity by selectively depleting the exogenously injected diabetogenic T cells in Recombination-Activating Gene deficient NOD mice. These d-CD8+CD122+ Tregs from NOD chimeras show upregulation of Helios, Programmed cell death protein 1, perforin, granzyme-B, CD39, Folate receptor 4, and downregulation of proinflammatory markers like Scart1 and Scart2. Using in vitro assays, we show that d-CD8+CD122+ Tregs respond specifically to a Complementarity-Determining Region-3 peptide sequence derived from T cell receptors of islet antigen-specific autoreactive T cells. Similarly, we found that individuals with T1D have a deficiency in CD8+CD122+ Tregs, suggesting a potential loss of regulatory function accompanies disease onset. Revitalizing CD8+CD122+ Tregs may offer a new therapeutic strategy of restoring immune tolerance in autoimmune diabetes.

immunology↗

Polymer of methyl malonic acid suppress inflammation by downregulating IL-2 through ROS overproduction

Metabolites belonging to the propionate metabolism pathway can regulate immune cell responses in the context of autoimmunity and chronic inflammation. Methyl malonic acid (MMA), a metabolite in this pathway is known to cause dysregulation of T cell oxidative phosphorylation (OXPHOS) and downregulating pro inflammatory T cell effector functions. However, the effects of MMA on T cell signaling and T cell activation is not clearly known. Furthermore, since MMA is a small molecule, using it in the context of therapy remains a problem. It gets metabolized in a short time and millimolar concentrations are required to get effective results. This work describes a novel polymer, 1,6 MMA, synthesized using 1,6 Hexane-diol and MMA, which helps in slow, steady and continuous release of the small molecule. Doses in micromolar ranges generate long lasting and robust immunosuppression of activated T cells via an IL2 dependent mechanism in both human and mice T cells without causing non-specific toxicity. This causes a dysregulated expression of pSTAT5 which eventually enhances BLIMP1 mediated T cell apoptosis. Finally, 1,6 MMA mediated T cell suppression is caused due to increase in mitochondrial ROS production. Extrapolation of our findings in-vivo showed the polymer inhibited autoreactive T cell responses in mice with collagen induced arthritis (CIA). Overall, 1,6 MMA, a novel metabolite polymer, has major therapeutic potential in combating inflammatory disorders.

bioengineering↗

Molecular basis for thermoresponsive protein condensation in plants

Plants continuously experience temperature fluctuations that shape their physiology, development, and survival. Yet, how plants sense and adapt to elevated temperatures at the molecular level remains only partially understood. Here, we uncover a sequence-encoded mechanism by which plant proteins directly sense temperature through phase separation. Focusing on prion-like low-complexity domains (PLCDs) in Arabidopsis thaliana, we combine cellular imaging, quantitative biophysics, and coarse-grained molecular dynamics simulations to show that numerous PLCDs undergo reversible lower critical solution temperature (LCST)-type transitions. We find that PLCDs that are sufficient and necessary for phase separation confer thermoresponsive variability to full-length proteins. Sequence analysis and simulations reveal that thermoresponsiveness is encoded in compositional heuristics, with sufficient PLCDs enriched in aliphatic and aromatic residues, enabling accurate prediction and rational tuning of condensation thresholds. Engineered variants with altered sequence composition exhibit predictable shifts in thermoresponsive behavior, confirming a direct, sequence-level encoding of temperature sensitivity. Our findings establish LCST-driven phase separation as a fundamental mechanism of thermoresponsiveness in plants and provide a molecular framework for designing synthetic biomolecules with programmable temperature responses.

biophysics↗

Generating ecological baselines on short-grass formations or grazing lawns in Central Terai landscape

Short-grass formations or the "grazing lawns" as they are popularly called support large congregations of mammalian herbivores globally. These systems are known to be maintained by cyclic process of grazing and nutrient deposition in the soil by foraging animals. The basic ecological characteristics of these short-grass systems have extensively been studied in the African context with little understanding particularly from the Himalayan foothills in Terai. In this study, we focused on understanding the ecological baselines such as grass species associations and associated nutrient content in these grazing lawns and tall grass formations across two protected areas of the Uttar Pradesh Terai in India. Our results show that, the protected areas had relatively similar grass species composition and associated nutrient content in the short-grass formations. However, when compared with tall grass formations, the grazing lawns differed markedly in both their grass associations and thus forage quality. Therefore, the results from this study indicate the need to maintain such grazing lawn habitats within the characteristic tall-wet grasslands of the Terai. This also indicates the importance of short-grass formations in providing palatable forage to the mammalian herbivores particularly in peak dry seasons of autumn and winters.

ecology↗

Curing autoimmune diabetes with islet and hematopoietic cell transplantation after CD117 antibody-based conditioning

Mixed hematopoietic chimerism after allogeneic hematopoietic cell transplantation (HCT) promotes tolerance of transplanted donor-matched solid organs, corrects autoimmunity, and could transform therapeutic strategies for autoimmune type 1 diabetes (T1D). However, development of non-toxic bone marrow conditioning protocols is needed to expand clinical use. We developed a chemotherapy-free, non-myeloablative (NMA) conditioning regimen that achieves mixed chimerism and allograft tolerance across MHC barriers in NOD mice. We obtained durable mixed hematopoietic chimerism in prediabetic NOD mice using anti-c-Kit monoclonal antibody, T-cell depleting antibodies, JAK1/2 inhibition, and low-dose total body irradiation prior to transplantation of MHC-mismatched B6 hematopoietic cells, preventing diabetes in 100% of chimeric NOD:B6 mice. In overtly diabetic NOD mice, NMA conditioning followed by combined B6 HCT and islet transplantation durably corrected diabetes in 100% of chimeric mice without chronic immunosuppression or graft-versus-host disease (GVHD). Chimeric mice remained immunocompetent, as assessed by blood count recovery and rejection of 3rd party allogeneic islets. Adoptive transfer studies and analysis of autoreactive T cells confirmed correction of autoimmunity. Analysis of chimeric NOD mice revealed central thymic deletion and peripheral tolerance mechanisms. Thus, with NMA conditioning and cell transplantation, we achieved durable hematopoietic chimerism without GVHD, promoted islet allograft tolerance, and reversed established T1D. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=197 SRC="FIGDIR/small/673576v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@23fcdorg.highwire.dtl.DTLVardef@1aac97borg.highwire.dtl.DTLVardef@191e06forg.highwire.dtl.DTLVardef@25be2b_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗

Differential gene expression drives cell-cycle-dependent transition from monopolar to bipolar growth in fission yeast.

Cell polarity is important for maintaining cell structure and function. In S. pombe, after division, cells are monopolar and grow from the old end that existed from the previous generation. Cells transition to bipolar growth once the cell reaches a certain size, when the new end generated after division initiates growth. Bipolarity occurs as a consequence of cell growth, where the two cell ends have sufficient growth-promoting factors. However, the transition to bipolarity does not occur in G1-arrested cells even with enhanced cell growth, suggesting a role for the cell-cycle phase in this process. To identify how the cell cycle impacts monopolar to bipolar transition, we performed high-throughput mRNA sequencing to detect differentially expressed genes in G1/S-arrested and G2-phase cells of the cell cycle mutant cdc10-129. Gene expression analysis using the DESeq2 R package identified 65 unique genes upregulated in G1/S phase and 35 in G2 phase cells. Enrichment analysis shows that G1/S phase cells upregulated the MAPK pheromone-response pathway, protein folding, rRNA processing, and heat-shock protein binding. G2 phase cells showed upregulation of plasma membrane maintenance and cell wall organization. Protein-protein interaction networks identified the cdc15-hob3-rho1-bgs1 hub in G2 phase cells. These genes are known to promote bipolar growth and regulate cell wall biogenesis. In G1/S phase cells spk1-byr2-ste11 hub was identified, which is required for pheromone-response and nutritional stress-dependent G1-arrest. We find that Spk1 also prevents precocious bipolar growth. Thus, we hypothesize that the pheromone response pathway, in addition to promoting G1-G0 transition, also prevents bipolar growth. In nutrient-rich conditions, this pathway is downregulated, G1-arrest is alleviated, the cell cycle progresses, and bipolarity occurs. Our findings suggest that in nutrition-rich conditions, stress response pathways are downregulated enabling transition from monopolar to bipolar growth, along with cell cycle progression.

cell biology↗

12-Hydroxystearic acid induces epidermal keratinocytes to secrete antimicrobial peptides that are potent inhibitors of viral infection.

Epidermal keratinocytes produce antimicrobial peptides (AMPs) that serve as a crucial component of the skins innate immune barrier. These peptides effectively target a broad spectrum of pathogenic microorganisms while preserving commensal microbiota essential for skin barrier homeostasis and overall skin health. Regulating the release of these AMPs presents a promising approach to enhancing the skin barriers defense mechanisms with minimal side effects. We have identified 12-hydroxystearic acid (12-HSA) as a potent stimulator of AMP secretion from primary epidermal keratinocytes. Mechanistic investigations revealed that, akin to bacterial stimulation, 12-HSA induces AMP release through the downregulation of caspase-8, which subsequently activates the inflammasome. Notably, we discovered that 12-HSA mediates caspase-8 downregulation via the acute activation of DNA methyltransferase 3A (DNMT3A), leading to transcriptional silencing of the caspase-8 locus. Importantly, 12-HSA is widely utilized in the cosmetic industry for its several skin beneficial properties including hydration and emolliency. Our findings suggest that this compound can be leveraged to enhance innate immune defenses in the skin, effectively mobilizing stored AMPs from keratinocytes to counteract microbial threats. This discovery highlights the potential for 12-HSA as a novel agent in dermatological applications aimed at fortifying skin barrier immunity.

cell biology↗

Improved conditioning for hematopoietic chimerism induces islet tolerance to cure diabetes

Mixed hematopoietic chimerism after hematopoietic cell transplantation (HCT) can modulate the immune system and induce tolerance to allogeneic tissues. However, bone marrow conditioning-related toxicities preclude wider adoption of HCT for transplant allotolerance. We sought agents that reduced conditioning intensity, while promoting durable mixed chimerism after HCT across complete major histocompatibility complex (MHC) mismatch in diabetic mice, permitting islet allotransplantation and diabetes reversal. We systematically tested baricitinib (JAK1/2 inhibitor), venetoclax (Bcl2 inhibitor), and CD47 antibody, agents in current clinical use, and quantified hematopoietic chimerism after HCT. Combined with CD117 antibody, transient T cell depletion, and just 10 centigray (cGy) total body irradiation (TBI), these agents enabled durable mixed chimerism and matching allo-islet tolerance, to cure diabetes without evidence of GVHD. Thus, we have developed a conditioning regimen to promote allogeneic mixed hematopoietic chimerism and transplanted islet allotolerance that minimizes conditioning radiation and cures diabetes, a significant achievement.

immunology↗

Autoantibodies in patients with arrhythmogenic cardiomyopathy activate GSK-3β resulting in a loss of cardiomyocyte cohesion

Arrhythmogenic cardiomyopathy (ACM) is an inherited cardiac desmosome disease, as more than 50% of affected patients carry pathogenic variants in desmosome protein-coding genes., In this study, we focused on the role and mechanisms of pathogenic and non-pathogenic autoantibodies against intercalated disc (ICD) proteins such as desmoglein2 (DSG2) in ACM patients, healthy relatives and murine ACM models. IgG fractions from ACM patients and healthy relatives, but not murine ACM model-derived or healthy control IgGs, revealed positive ICD staining. Antibodies reducing the loss of cardiomyocyte cohesion were found in three out of five ACM patients. Pathogenic autoantibodies, bound to DSG2 in hiPSC-CMs, cleaved DSG2 and reduced DSG2 interaction at the molecular level. We investigated GSK-3{beta} contribution to the loss of cardiomyocyte cohesion and observed that GSK-3{beta} reduced baseline cardiomyocyte cohesion in cultured cardiomyocytes and cardiac slices. Pathogenic ACM-IgGs activated GSK-3{beta} upstream of p38MAPK, leading to phosphorylation and junctional loss of {beta}-catenin. GSK-3{beta} inhibition rescued the loss of cell cohesion induced by ACM-IgGs in ACM hiPSC-CMs. Pathogenic autoantibodies targeting DSG2 are present in ACM patients and impair cardiomyocyte cohesion in a GSK-3{beta}-dependent manner. In contrast, autoantibodies are absent in murine ACM models and are non-pathogenic in some patients, healthy relatives.

cell biology↗

Remote sensing of endogenous pigmentation by inducible synthetic circuits in grasses

Plant synthetic biology holds great promise for engineering plants to meet future demands. Genetic circuits are being designed, built, and tested in plants to demonstrate proof of concept. However, developing these components in monocots, which the world relies on for grain, lags behind dicot models, such as Arabidopsis thaliana and Nicotiana benthamiana. Here, we show the successful adaptation of a ligand-inducible sensor to activate an endogenous anthocyanin pathway in the C4 monocot model Setaria viridis. We identify two transcription factors sufficient to induce endogenous anthocyanin production in S. viridis protoplasts and whole plants in a constitutive or ligand-inducible manner. We also test multiple ligands to overcome physical barriers to ligand uptake, identifying triamcinolone acetonide (TA) as a highly potent inducer of this system. Using hyperspectral imaging and a discriminative target characterization method in a near-remote configuration, we can non-destructively detect anthocyanin production in leaves in response to ligands. This work demonstrates the use of inducible expression systems in monocots to manipulate endogenous pathways, stimulating plants to overproduce secondary metabolites with value to human health. Applying inducible pigmentation coupled with sensitive detection algorithms could enable crop plants to report on the status of field contamination or detect undesirable chemicals impacting agriculture, ushering in an era of agriculture-based sensor systems. SummaryO_ST_ABSSynbio tools for C4 grass modelC_ST_ABS[bullet] Advantage of synthetic switches as tools for biopharming and functional genomics [bullet]Our workflow to optimize the gene circuits from a transient system to a stable transgenic [bullet]Testing and taming golden gate elements in monocot system, S. viridis

plant biology↗

Nanotopographic Control of Actin Waves and Growth Cone Navigation in Developing Neurons

The development of axons and dendrites (neurites) in a neural circuit relies on the dynamic interplay of cytoskeletal components, especially actin, and the integration of diverse environmental cues. Building on prior findings that actin dynamics can serve as a primary sensor of physical guidance cues, this work investigates the role of nanotopography in modulating and guiding actin waves and neurite-tip dynamics during early neural circuit development. Although actin dynamics is well known to contribute to pathfinding in wide axonal tips, typically referred to as growth cones, we also observe dynamic actin remodeling throughout neurites and at other, narrower, neurite tips. We find that actin-wave speeds do not change significantly in the first two weeks of neurite development on flat substrates, but decrease over the same period in neurites on nanoridges. The ability of nanoridges to guide actin waves and the neurite-tip direction also decreases as neurites mature, both for narrow tips and wide growth cones. This change in responsiveness to physical guidance cues with neuronal maturation may impact the regenerative capacity of developing neural cells that are inserted into mature brains.

biophysics↗

Macrophage migration inhibitory factor is a potential therapeutic target for cisplatin induced peripheral neuropathy in breast cancer

BackgroundCisplatin (CP) is an effective chemotherapy drug for several cancers. However, the use of CP is associated with peripheral neuropathy, a painful nerve disorder. Unfortunately, no therapies are available for CP-induced peripheral neuropathy (CisIPN). This study explored the role of a cytokine, the macrophage migration inhibitory factor (MIF), as a potential therapeutic target for CisIPN. MethodsThe role of neuroinflammation and MIF in CisIPN was evaluated in mice models of CisIPN, with and without breast cancer, after treatment with the anti-inflammatory drug Dexamethasone (Dex). Circulating MIF levels in animals were examined using ELISA. Pharmacological inhibition of MIF was achieved using the small molecule inhibitors, CPSI-1306 and ISO-1. Mechanical and thermal sensitivities of animals were assessed using von frey filament and cold acetone assays. Macrophage infiltration in peripheral nerve tissues was examined using CD68 and Iba-1 staining. ResultsOur results showed that Dex suppressed mechanical hyperalgesia in CisIPN animals, which was accompanied by downregulation of MIF. We also found that circulating MIF levels were increased in CisIPN animals. Furthermore, direct inhibition of MIF using CPSI-1306 and ISO-1 led to suppression of mechanical hyperalgesia, without compromising the anti-tumor efficacy of CP, in CisIPN animals. We did not find any significant change in macrophage infiltration in the peripheral nerve tissues of CisIPN animals. Immunostaining results indicated that sensory neurons in the DRGs and Schwann Cells in the sciatic nerves are potential sources for increased MIF in CisIPN. InterpretationOverall, our results strongly suggest that MIF is a promising therapeutic target for CisIPN.

neuroscience↗

Apremilast improves cardiomyocyte cohesion and arrhythmia in different models for arrhythmogenic cardiomyopathy

BackgroundArrhythmogenic cardiomyopathy (ACM) is a genetically inherited desmosome heart disease leading to life-threatening arrhythmias and sudden cardiac death. Currently, ACM treatment paradigms are merely symptom targeting. Recently, apremilast was shown to stabilize keratinocyte adhesion in the desmosomal disease pemphigus vulgaris. Therefore, this study investigated whether apremilast can be a therapeutic option for ACM. MethodsHuman induced pluripotent stem cells from a healthy control (hiPSC) and an ACM index patient (ACM-hiPSC) carrying a heterozygous desmoplakin (DSP) gene mutation (c.2854G>T, p.Glu952Ter), confirmed by whole exome sequencing (WES), were established. Cyclic-AMP ELISA, dissociation assay, immunostaining, and Western blotting analyses were performed in human iPSC-derived cardiomyocytes (hiPSC-CMs), murine HL-1 cardiomyocytes, and cardiac slices derived from wild-type (WT) mice, plakoglobin (PG, Jup) knockout (Jup-/-) (murine ACM model) or PG Serine 665 phosphodeficient (JUP-S665A) mice. Microelectrode array (MEA) analyses in ventricular cardiac slices and Langendorff heart perfusion were performed to analyze heart rate variability and arrhythmia. ResultsACM-hiPSC derived cardiomyocytes (ACM-hiPSC-CMs) revealed a significant loss of cohesion, which was rescued by apremilast. Further, treatment with apremilast strengthened basal cardiomyocyte cohesion in HL-1 cells and WT murine cardiac slices, paralleled by phosphorylation of PG at Serine 665 in human and murine models. In HL-1 cells, apremilast in addition activated ERK1/2, inhibition of which abolished apremilast-enhanced cardiomyocyte cohesion. Further, dissociation assays in slice cultures from JUP-S665A and Jup-/- mice revealed that PG is crucial for apremilast-enhanced cardiomyocyte cohesion. In parallel to enhanced cell adhesion, MEA and Langendorff measurements from WT and Jup-/- mice demonstrated decreased heart rate variability and arrhythmia after apremilast treatment. ConclusionsApremilast improves loss of cardiomyocyte cohesion, enhances localization of DSG2, and reduces arrhythmia in human and murine models of ACM ex vivo and in vitro, providing a novel treatment strategy for ACM by preserving desmosome function. Translational perspectiveThe current therapeutic options for patients with arrhythmogenic cardiomyopathy (ACM) include lifestyle changes, treatment with anti-arrhythmic drugs, catheter ablation, implantable cardiac defibrillators, and ultimately, heart transplantation for patients who are having therapy refractory arrhythmia or developed heart failure. However, lifestyle changes, such as restraining from physical endurance activities and {beta}-blocker therapy, are most used in patients carrying genetic variants coding for proteins of the desmosomal complex. Recent advancements hint that strategies enhancing intracellular cAMP could be beneficial in treating desmosomal diseases and can be effective therapeutics, which would be highly relevant for ACM patients. In this study, we show that apremilast improves loss of cardiomyocyte cohesion, enhances localization of desmosomal proteins, and reduces arrhythmia in both human and murine models of ACM ex vivo and in vitro, providing a novel treatment strategy for ACM by preserving desmosome function.

cell biology↗