Biology subjects

Rathod, M.

Publications and source records attributed to Rathod, M..

7 recordsLinked to original sources

bioRxiv2026

Brain-derived neurotrophic factor (BDNF), estrogen receptors, and mossy cells

Dentate gyrus (DG) function depends on the neurotrophin brain-derived neurotrophic factor (BDNF) which shows robust synthesis in the principal cells, the granule cells (GCs). However, BDNF protein is present in the inner molecular layer (IML), where most afferents to GCs are from hilar mossy cells (MCs). Therefore, we asked whether MCs express BDNF mRNA and protein. Using adult mice, we found that MC BDNF mRNA and protein were expressed in the majority of MC somata and few other hilar neurons. Interestingly, IML BDNF was significantly greater in the ventral compared to dorsal DG. Additionally, dorsal IML BDNF was significantly higher in females on proestrous morning, when serum levels of estrogen peak, relative to metestrous morning, when estrogen is lower. Consistent with this observation, ventral MC somata, which project to the dorsal IML, showed more BDNF mRNA on proestrous morning than metestrous morning. Next, we asked if strong IML BDNF protein expression on proestrous morning was due to estrogen action at estrogen receptors (ERs) because estrogen binding to ERs can increase BDNF synthesis. We found that MCs have high expression of all ERs: ER, ER{beta} and GPER1 in both sexes. When sexes were pooled, the percent of MCs labeled by ER{beta} and GPER1 exceeded the percent of MCs expressing ER. When proestrous females were examined, GPER1-labeled hilar cells were greater than hilar cells labeled by ER. The results demonstrate robust MC somatic expression of BDNF, relatively high ventral IML expression of BDNF, and estrous cycle dependence. The results also highlight robust MC ER expression, especially ER{beta} and GPER1, making the hilus a previously underestimated site of estrogen and BDNF action.

neuroscience↗

bioRxiv2026

Nuclear SUN2 coordinates endothelial cell-matrix interactions to regulate blood vessel homeostasis and barrier function

Vascular endothelial cells respond to environmental forces to remodel vessels during development and to achieve homeostasis, and mis-regulated responses lead to vascular dysfunction and disease. The nucleus participates in force transduction to cell-matrix junctions via the Linker of Nucleoskeleton and Cytoskeleton (LINC) complex that resides in the nuclear envelope, but how these forces are regulated and relayed is incompletely understood. We found that the LINC complex protein SUN2 is required for proper endothelial cell-matrix interactions that occur far from the nucleus and affect angiogenic expansion, vascular responses to flow, and barrier integrity. Endothelial cells lacking SUN2 had inappropriate flow responses and reduced expression of flow-mediated transcription factors in vitro and in vivo. Expression of several matrix and adhesion genes was reduced in SUN2-depleted cells, leading to defective extracellular matrix, dysmorphic focal adhesions resistant to dynamic turnover, and disturbed cell-matrix force distribution. Mechanistically, nuclear SUN2 affected dynamic regulation of the microtubule cytoskeleton that correlated with matrix metalloprotease-dependent barrier dysfunction. These findings indicate that nuclear SUN2 establishes and maintains blood vessel homeostasis by controlling microtubule-mediated effects on focal adhesion turnover and extracellular matrix properties, with implications for cardiovascular aging and diseases such as Marfan syndrome that affect vessel wall integrity.

cell biology↗

bioRxiv2025

Chemogenetic activation of hippocampal area CA2 promotes acute and chronic seizures in a mouse model of epilepsy

Pyramidal cells (PCs) of hippocampal area CA2 exhibit increased excitability in temporal lobe epilepsy (TLE) and in mouse models of TLE. In epileptic mice, selective inhibition of CA2 PCs reduces chronic seizures. Here we asked if activating CA2 PCs increases seizures. Mice expressing Cre recombinase in CA2 PCs (Amigo2-Cre mice) were injected with the convulsant pilocarpine to induce a period of severe seizures (status epilepticus, SE), which leads to chronic seizures after 3-4 weeks (epilepsy). Epileptic mice were injected with a Cre-dependent adeno-associated virus (AAV) to express an excitatory designer receptor exclusively activated by designer drug (eDREADD; hM3Dq) in dorsal CA2 bilaterally and implanted with subdural EEG electrodes. After recovery, mice were recorded continuously using video and EEG for 6 weeks, 3 weeks with drinking water containing the eDREADD activator clozapine-N-oxide (CNO) and 3 weeks without CNO. CA2 activation with CNO caused a significant increase in seizure frequency and duration. Seizures occurred in clusters (many seizures per day over several consecutive days) and mice given water with CNO had a greater maximum number of seizures per day during a cluster compared to water without CNO. CNO had no significant effect in control mice. In naive Amigo2-Cre mice expressing hM3Dq, pre-treatment with CNO before pilocarpine administration shortened the latency to SE and increased EEG power at the start of SE. Taken together with prior findings, the results suggest that CA2 is a control point for regulating seizures in the pilocarpine mouse model of TLE. HIGHLIGHTSO_LIChemogenetic excitation of CA2 increased chronic seizure frequency and duration in epileptic mice. C_LIO_LIWhen seizures occurred in clusters, CA2 excitation increased the peak of the cluster. C_LIO_LIWhen sexes were separated, males showed effects on seizure frequency but both sexes showed effects on seizure duration and clusters. C_LIO_LIChemogenetic excitation of CA2 promoted pilocarpine-induced status epilepticus in normal mice. C_LI GRAPHICAL ABSTRACTLegend: In adult mice, injecting the convulsant pilocarpine induces severe seizures (status epilepticus, SE) and ultimately leads to chronic intermittent seizures (epilepsy). Selective activation of hippocampal area CA2 during the period of chronic seizures led to greater seizure frequency and duration, as well as a greater number of seizures/day at the peak of a seizure cluster. Effects were greatest in males. In naive mice, activation of CA2 prior to pilocarpine administration facilitated SE. Therefore, CA2 influences acute and chronic seizures in this mouse model. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=73 SRC="FIGDIR/small/696896v1_ufig1.gif" ALT="Figure 1"> View larger version (16K): org.highwire.dtl.DTLVardef@174f63dorg.highwire.dtl.DTLVardef@1d2478corg.highwire.dtl.DTLVardef@573c56org.highwire.dtl.DTLVardef@13a72e7_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

Microphysiological uremia model reveals biophysical potentiators of vascular dysfunction

Cardiovascular disease is a leading cause of mortality in individuals with chronic kidney disease. Hypertension, common among patients with chronic kidney disease, is a major contributor to both kidney damage and the heightened cardiovascular risk in these patients. Advanced chronic kidney disease is associated with elevated levels of circulating uremic toxins, particularly indoxyl sulfate and p-cresyl sulfate, and are known to exacerbate cardiovascular risk by promoting inflammatory processes, including monocyte adhesion, rolling, and extravasation. However, despite the established link between chronic kidney disease and cardiovascular disease, the specific role of uremic toxins in monocyte-endothelial interactions in hypertensive settings remains largely underexplored. In this study, we developed a 3D microfluidic model to examine the effects of indoxyl sulfate on monocyte adhesion and extravasation across engineered microvessels embedded in collagen hydrogels with different densities under controlled luminal pressure. We found that elevated pressure alone significantly enhanced monocyte adhesion and extravasation, regardless of matrix density, and that the uremic environment further increased these effects. Additionally, denser hydrogels primed THP-1 monocyte cells toward a pro-inflammatory like phenotype with reduced phagocytic capacity, while softer hydrogels induced an anti-inflammatory like phenotype with enhanced phagocytosis. However, exposure to the uremic environment diminished phagocytosis and shifted cells toward a pro-inflammatory like state, irrespective of matrix density. The presented approach has the potential to experimentally dissect multiple factors that contribute to elevated cardiovascular risks in chronic kidney disease patients and improve the understanding of mechanisms involved in monocyte dynamics in chronic kidney disease- related cardiovascular disease.

bioengineering↗

bioRxiv2024

SERPINB5-TGF-β signalling modulates desmoplakin membrane localization and ameliorates pemphigus vulgaris skin blistering

Impairment of desmosomal cell-cell adhesion leads to several life-threatening diseases such as the autoimmune skin blistering disorder pemphigus vulgaris (PV). Disease management strategies that stabilize intercellular adhesion, in addition to the existing immunosuppression therapies, may result in improved clinical outcomes. Previous findings showed that the serine protease inhibitor SERPINB5 promotes intercellular adhesion by binding to and regulating the localization of the desmosomal adapter molecule desmoplakin (DSP) at the plasma membrane. We here show that SERPINB5 overexpression prevents PV-IgG-mediated loss of cell-cell adhesion and the loss of DSP from the cell membrane. We mechanistically demonstrate that SERPINB5 loss deregulates TGF-{beta} signalling, a pathway known to destabilize DSP in keratinocytes. TGF-{beta} signalling was also activated in skin biopsies of PV patients and keratinocytes treated with PV autoantibodies, suggesting a contribution to disease. Inhibition of TGF-{beta} activation ameliorated PV-IgG-mediated loss of cell-cell adhesion, increased DSP membrane expression, and prevented PV-IgG-induced blister formation in a human ex-vivo skin model. Together, SERPINB5 modulates DSP and intercellular adhesion through the regulation of TGF-{beta} signalling. Further, TGF-{beta} signalling was identified as a potential target for pemphigus treatment.

cell biology↗

bioRxiv2024

Dysfunctional mechanotransduction regulates the progression of PIK3CA-driven vascular malformations

Somatic activating mutations in PIK3CA are common drivers of vascular and lymphatic malformations. Despite common biophysical signatures of tissues susceptible to lesion formation, including compliant extracellular matrix and low rates of perfusion, lesions vary in clinical presentation from localized cystic dilatation to diffuse and infiltrative vascular dysplasia. The mechanisms driving the differences in disease severity and variability in clinical presentation and the role of the biophysical microenvironment in potentiating progression are poorly understood. Here, we investigate the role of hemodynamic forces and the biophysical microenvironment in the pathophysiology of vascular malformations, and we identify hemodynamic shear stress and defective endothelial cell mechanotransduction as key regulators of lesion progression. We found that constitutive PI3K activation impaired flow-mediated endothelial cell alignment and barrier function. We show that defective shear stress sensing in PIK3CAE542Kendothelial cells is associated with reduced myosin light chain phosphorylation, junctional instability, and defective recruitment of vinculin to cell-cell junctions. Using 3D microfluidic models of the vasculature, we demonstrate that PIK3CAE542Kmicrovessels apply reduced traction forces and are unaffected by flow interruption. We further found that draining transmural flow resulted in increased sprouting and invasion responses in PIK3CAE542K microvessels. Mechanistically, constitutive PI3K activation decreased cellular and nuclear elasticity resulting in defective cellular tensional homeostasis in endothelial cells which may underlie vascular dilation, tissue hyperplasia, and hypersprouting in PIK3CA-driven venous and lymphatic malformations. Together, these results suggest that defective nuclear mechanics, impaired cellular mechanotransduction, and maladaptive hemodynamic responses contribute to the development and progression of PIK3CA-driven vascular malformations.

bioengineering↗

bioRxiv2022

Desmosomal cell cohesion and epidermal differentiation are modulated by dolichol phosphate mannosyltransferase 1 (DPM1) through SERPINB5-dependent mechanisms

Glycosylation is essential to facilitate cell-cell adhesion and differentiation. We determined the role of the dolichol phosphate mannosyltransferase (DPM) complex, a central regulator for glycosylation, for desmosomal adhesive function and epidermal differentiation. Deletion of the key molecule of the DPM complex, DPM1, in human keratinocytes resulted in weakened cell-cell adhesion, impaired localization of the desmosomal components desmoplakin and desmoglein-2, and led to cytoskeletal organization defects in human keratinocytes. In a 3D organotypic human epidermis model, loss of DPM1 caused impaired differentiation with abnormally increased cornification, reduced thickness of non-corneal layers, and formation of intercellular gaps in the epidermis. Using proteomic approaches, SERPINB5 was identified as DPM1-dependent interaction partner of desmoplakin. Mechanistically, SERPINB5 reduced desmoplakin phosphorylation at serine 176, which was required for strong intercellular adhesion. These results uncover a novel role of the DPM complex in linking desmosomal adhesion with epidermal differentiation.

cell biology↗