Biology subjects

Parmar, N.

Publications and source records attributed to Parmar, N..

12 recordsLinked to original sources

bioRxiv2025

Melatonin and GABA monotherapies are as efficacious as combination therapy in managing T1D and T2D: In-vivo studies on experimental diabetic models

BackgroundLoss of functional {beta}-cell mass is a critical factor in the ontogenesis of type 1 (T1D) and type 2 diabetes (T2D) marked by chronic hyperglycemia. Melatonin (M) and {gamma}-aminobutyric acid (GABA/G) have immunoregulatory properties and have shown potential to increase {beta}-cell mass in experimental diabetic models. Thus, we aimed to investigate the therapeutic potential of melatonin combined with GABA on {beta}-cell regeneration in streptozotocin (STZ)-induced T1D and on a high-fat diet (HFD)-induced T2D mouse models. MethodsThe BALB/c mice were injected with 50 mg/kg body weight STZ on five consecutive days to induce T1D and were subjected to six weeks of monotherapy with melatonin or GABA and combination therapy (M+G). HFD was fed to C57BL/6J mice for 30 weeks to induce insulin resistance and T2D, followed by six weeks of mono or combination therapy exposure. ResultsOur studies on monotherapies and combination therapy reduced fasting blood glucose levels, increased plasma insulin levels and glucose tolerance, and promoted {beta}-cell proliferation and transdifferentiation, with a simultaneous decrease in {beta}-cell apoptosis in T1D mice. It also improved metabolic parameters and glycolipid metabolism in the liver and adipose tissue, respectively, and increased mitochondrial function in the skeletal muscle. Moreover, it restored peripheral insulin sensitivity and {beta}-cell mass in T2D mice. ConclusionOur studies suggest that monotherapies are as effective as combination therapy since melatonin and GABA sub-additively ameliorates T1D and T2D manifestations.

biochemistry↗

bioRxiv2024

One Health assessment of poultry and cattle farms as reservoirs for ESBL-producing Escherichia coli

BACKGROUNDUnregulated use of antibiotics in animal food production leads to the emergence of multidrug resistant bacteria, notably extended-spectrum beta-lactamases producing Escherichia coli (ESBL E. coli). ESBLs severely limit treatment options and pose a significant threat to public health. Investigating the potential role of livestock and poultry farms in harboring ESBL E. coli is crucial, given the prevalence of ESBL E. coli in humans, animals, and the environment, following the One Health framework. OBJECTIVESThe aim of this study was to assess and compare the potential contribution of cattle and poultry farms along with their respective human handlers to the emergence and spread of ESBL E. coli following One Health approach. METHODSTwenty cattle and twenty poultry farms were surveyed in Ludhiana, India to determine antibiotic usage, prevalent diseases in the farms. Animal faeces/poultry droppings, handler hand swabs, and stool samples were examined for the presence of ESBL E. coli. The isolates were examined for their susceptibility to 16 antibiotics and for the presence of selected antimicrobial resistance genes, including ESBL genes. Generalized linear mixed models were applied to investigate variations in the prevalence of ESBL E. coli associated with farm animal species, farm practices, and farm biosecurity measures. RESULTSOur findings revealed a higher prevalence of ESBL E. coli in poultry farms (53.75%) than in cattle farms (40.72%) and overall lower prevalence (12%) in human handlers. Of the total isolates, 86.52% were multidrug resistant, and 93.91% showed a high multiple antibiotic resistance (MAR) index (>0.2). Isolates from poultry farms exhibited a higher level of resistance with 97% of isolates exhibiting multidrug resistance, 100% isolates with MAR index of more than 0.2, and 90.70% carrying the blaCTXM gene. CONCLUSIONOur findings highlight cattle and poultry farms as potential reservoirs for multidrug-resistant and ESBL E. coli, contributing to the rising environmental burden of antibiotic resistance genes. This emphasizes the urgency of limiting antibiotic use in animal farming, especially in poultry production, to address the escalating problem of antibiotic resistance and protect both animal and human health.

microbiology↗

bioRxiv2023

Postnatal intestinal epithelial maturation by LSD1 controls the small intestinal immune cell composition independently from the microbiota

Postnatal development of the gastrointestinal tract involves the establishment of the commensal microbiota, maturation of the intestinal epithelium, and the acquisition of immune tolerance via a balanced immune cell composition. While studies have uncovered an interplay between the commensal microbiota and immune system development, less is known about the role of the maturing epithelium. Here, we comprehensively show that intestinal-epithelial intrinsic expression of lysine-specific demethylase 1A (LSD1) is necessary for the postnatal maturation of intestinal epithelium as well as maintaining this developed epithelial state in adulthood. Although the stool microbiome was altered in animals with an intestinal-epithelial specific deletion of Lsd1, by depleting the microbial component using antibiotics, we found that the cellular state and number of certain immune cell types were dependent on maturation of the epithelium. We found plasma cells, innate lymphoid cells (ILCs), and a specific myeloid population to be depending on epithelial LSD1 expression. We propose that LSD1 controls the expression of epithelial-derived chemokines, such as Cxcl16, and this is a mode of action for this epithelial-immune cell interplay. For example, we show that LSD1-mediated epithelial-intrinsic CXCL16 controls the number of local ILC2s but not ILC3s. Together, our findings suggest that the maturing epithelium plays a dominant role in regulating the local immune cell composition, thereby contributing to gut homeostasis.

immunology↗

bioRxiv2023

Mmp17-deficient mice exhibit heightened goblet cell effector expression in the colon and increased resistance to chronic Trichuris muris infection

Intestinal epithelial homeostasis is maintained by intrinsic and extrinsic signals. The extrinsic signals include those provided by mesenchymal cell populations that surround intestinal crypts and is further facilitated by the extracellular matrix (ECM), which is modulated by proteases such as matrix metalloproteinases (MMPs). Extrinsic signals ensure an appropriate balance between intestinal epithelial proliferation and differentiation. This study explores the role of MMP17, which is expressed by mesenchymal cells, in intestinal homeostasis and during immunity to infection. Mice lacking MMP17 expressed high levels of goblet-cell associated genes, such as CLCA1 and RELM-{beta}, which are normally associated with immune responses to infection. Nevertheless, Mmp17 KO mice did not have altered resistance during a bacterial Citrobacter rodentium infection. However, when challenged with a low dose of the helminth Trichuris muris, Mmp17 KO mice had increased resistance, without a clear role for an altered immune response during infection. Mechanistically, we did not find changes in traditional modulators of goblet cell effectors such as the NOTCH pathway or specific cytokines. Instead, we found elevated BMP signaling in Mmp17 KO mouse large intestinal crypts that we propose to alter the goblet cell maturation state. Together, our data suggests that MMP17 extrinsically alters the goblet cell maturation state via a BMP signaling axis, which is sufficient to alter clearance in a helminth infection model.

immunology↗

bioRxiv2023

Separate Gut Plasma Cell Populations Produce Autoantibodies Against Transglutaminase 2 and Transglutaminase 3 in Dermatitis Herpetiformis

Dermatitis herpetiformis (DH) is an inflammatory skin disorder often considered as an extraintestinal manifestation of celiac disease (CeD). Hallmarks of CeD and DH are autoantibodies to transglutaminase 2 (TG2) and transglutaminase 3 (TG3), respectively. DH patients have autoantibodies reactive with both transglutaminase enzymes. We here report that in DH both gut plasma cells and serum autoantibodies are specific for either TG2 or TG3 with no TG2-TG3 cross-reactivity. By generating monoclonal antibodies from TG3-specific duodenal plasma cells of DH patients, we define three conformational epitope groups. Both TG2-specific and TG3-specific gut plasma cells have few immunoglobulin mutations, and the two transglutaminase-reactive populations show distinct selection of certain heavy and light chain V-genes. Mass spectrometry analysis of TG3-specific serum IgA corroborates preferential usage of IGHV2-5 in combination with IGKV4-1. Collectively, our results demonstrate parallel induction of anti-TG2 and anti-TG3 autoantibody responses involving separate B-cell populations in DH patients.

immunology↗

bioRxiv2023

Myosin inhibitor reverses hypertrophic cardiomyopathy in pediatric iPSC-cardiomyocytes to mirror variant correction

Hypertrophic cardiomyopathy (HCM) is mainly caused by sarcomere gene variants in MYH7 and MYBPC3. Targeted drugs like myosin ATPase inhibitors have shown efficacy in adult HCM but have not been evaluated in children. We generated iPSC-cardiomyocytes (CMs) from four children with HCM harboring variants in MYH7 (V606M; R453C) or MYBPC3 (G148R; P955fs and TNNI3_A157P), variant-corrected controls, and a healthy individual. All CMs showed hypertrophy and sarcomere disorganization. All 3 single variant CMs showed higher contractility, slower relaxation, higher calcium transients and higher ATPase activity. Only MYH7 variant CMs showed stronger myosin-actinin binding. Targeted myosin ATPase inhibitor showed complete rescue of the phenotype in affected CMs and in cardiac Biowires to mirror isogenic controls. The response was stronger compared to verapamil or metoprolol, highlighting the need for clinical trials of myosin targeted therapy in pediatric HCM patients. The phenotype and response to drug therapy are influenced by the underlying genotype.

genetics↗

bioRxiv2023

Chronic industrial perturbation and seasonal change induces shift in the bacterial community from gammaproteobacteria to betaproteobacteria at Amlakhadi canal

Escalating proportions of industrially contaminated sites are one of the major catastrophes faced at the present time due to the industrial revolution. In the outlook of the obstacles associated with culturing the microbes, the direct metagenomic analysis of various complex niches is rapidly gaining attention. In this study, metagenomic approach using next generation sequencing technologies was applied to exemplify the taxonomic abundance and metabolic potential of the microbial community residing in Amlakhadi canal, Ankleshwar at two different seasons. All the metagenomes revealed a predominance of Proteobacteria phylum. However, difference was observed within class level where Gammaproteobacteria was relatively high in polluted metagenome in Summer while in Monsoon the abundance shifted to Betaproteobacteria. Similarly, significant statistical differences were obtained while comparing the genera amongst contaminated sites where Serratia, Achromobacter, Stenotrophomonas and Pseudomonas were abundant at one season and the dominance changed to Thiobacillus, Thauera, Acidovorax, Nitrosomonas, Sulfuricurvum, Novosphingobium, Hyphomonas and Geobacter at the next season. Further upon functional characterization, the microbiomes demonstrated diverse survival mechanisms adapted by the inherent microbial community such as degradation of aromatic compounds, heavy metal resistance, oxidative stress responses and multidrug resistance efflux pumps. The results have important implications in understanding and predicting the impacts of human-induced activities on microbial communities inhabiting natural niche and their responses in coping with the fluctuating pollution load.

microbiology↗

bioRxiv2021

Calorie Restriction in combination with GABA: improved glycaemic control in type 2 diabetes mouse model

AimDysfunctional adipocytes and {beta}-cells are crucial in the advancement of obesity-induced type 2 diabetes (T2D). Calorie restriction (CR) improves insulin sensitivity and fasting blood glucose (FBG) levels, while {gamma}-aminobutyric acid (GABA), a neurotransmitter secreted by {beta}-cells, exerts regenerative effects. MethodsHigh-fat diet (HFD) and streptozotocin (STZ) induced T2D mouse model was used to assess the effect of CR and GABA combination therapy. The mice were fed with CR diet (30% reduction of HFD) and treated with GABA (2.5 mg/kg i.p) daily for 5 weeks. Assessment of FBG, body weight (BW), insulin sensitivity, glucose tolerance, and estimation of plasma insulin and lipid profile were carried out by standard methods. The mRNA expression of target genes [liver (glucoregulatory enzymes), adipose tissue (lipid metabolism markers) and skeletal muscle (mitochondrial biogenesis markers)] was assessed by SYBR Green-qPCR. Oxygen consumption rate for mitochondrial complex I, II and III was measured in skeletal muscle using Oxytherm Clark-type oxygen electrode. The effect of monotherapies and combination treatment on pancreatic {beta}-cell regeneration and apoptosis was analysed by IHC. ResultsCR+GABA group showed significant reduction in FBG levels, improved lipid profile and whole-body insulin responsiveness as indicated by increased insulin levels, insulin sensitivity and glucose tolerance compared to the monotherapies. The transcript expression profile of glucoregulatory enzymes in the liver showed significant reduction in G6Pase, PEPCK, Glycogen Phosphorylase and increased GCK expression in CR+GABA group as compared to the monotherapies The ACC and ATG expression was up-regulated in adipose tissue; and significant increase in SIRT-1, PGC-1 and TFAM expression with up-regulated mitochondrial complex I and III activities was observed in CR+GABA group as compared to the monotherapies. Percentage of BrdU/Insulin and PDX1/Ngn3/Insulin co-positive cells was significantly higher in CR+GABA treated group than the monotherapy and HFD+STZ groups. Finally, there was a significant reduction in TUNEL/Insulin co-positive cells suggesting reduced apoptosis in CR+GABA treated group. ConclusionOur results suggest that CR in combination with GABA ameliorates T2D in HFD+STZ treated mice, by GABA induced {beta}-cell regeneration and CR mediated insulin sensitivity.

physiology↗

bioRxiv2021

Repurposing statin and L-glutamine: replenishing β-cells in hyperlipidemic T2D mouse model

While cases of obesity-induced type 2 diabetes (T2D) are on the upswing, current therapies help only manage the symptoms. Of late, L-glutamine has been implicated in the amelioration of T2D by virtue of its glucagon like peptide-1 (GLP-1) secretagogue property. Alongside, there are mixed reports on adiponectin (insulin sensitizer) potentiating property of statins. We aimed to investigate the effect of pitavastatin (P) and L-glutamine (LG) combination on glycemic control and pancreatic {beta}-cell regeneration in a high-fat diet (HFD)+Streptozotocin (STZ) induced T2D mouse model. C57BL6/J mice treated with HFD+STZ were randomly assigned into four groups: Diabetic control, L-glutamine, Pitavastatin and P+LG. Control group was fed with the chow diet. Significant amelioration in insulin resistance along with plasma glucose, lipid profile, adiponectin levels, and mitochondrial complexes I, II, III activities were observed in P+LG group as compared to HFD+STZ treated group. Phosphoenolpyruvate carboxykinase, glucose 6-phophatase, glycogen phosphorylase, and GLUT2 transcript levels were reduced with increased glycogen synthase transcript levels in liver. Further, the protein levels of Insulin receptor 1-{beta}, pAkt/Akt, and AdipoR1 were restored in the skeletal muscle and a significant increase in islet number as a result of {beta}-cell regeneration and reduced {beta}-cell death were also observed in the combination drug treated group. Thus, L-glutamine and pitavastatin in combination can induce {beta}-cell regeneration and regulate glucose homeostasis to bring about amelioration of HFD+STZ induced T2D.

biochemistry↗

bioRxiv2020

A semi-automated intestinal organoid screening method demonstrates epigenetic control of epithelial maturation

Intestinal organoids are an excellent model to study epithelial biology. Yet, the selection of analytical tools to accurately quantify heterogeneous organoid cultures remains limited. Here, we developed a semi-automated organoid screening method, which we applied to a library of highly specific chemical probes to identify epigenetic regulators of intestinal epithelial biology. The role of epigenetic modifiers in adult stem cell systems, such as the intestinal epithelium, is still undefined. Based on this resource data, we identified several targets that affected epithelial cell differentiation, including HDACs, EP300/CREBBP, LSD1, and type I PRMTs, which were verified by complementary methods. For example, we show that inhibiting type I PRMTs, which leads enhanced epithelial differentiation, blocks the growth of adenoma but not normal organoid cultures. Thus, epigenetic probes are powerful tools to study intestinal epithelial biology and may have therapeutic potential.

cell biology↗

bioRxiv2020

Developmental pathways regulate cytokine-driven effector and feedback responses in the intestinal epithelium

The intestinal tract is a common site for infection, and it relies on an appropriate immune response to defend against pathogens. The intestinal epithelium has an important role in effector responses, which is coordinated by immune-type specific cytokines. It is incompletely understood how cytokines drive epithelial responses. Here, using organoid-cytokine co-cultures, we provide a comprehensive analysis of how key cytokines affect the intestinal epithelium, and relate this to in vivo infection models. We use imaging, based on a convolutional neural network, and transcriptomic analysis to reveal that cytokines use developmental pathways to define intestinal epithelial effector responses. For example, we find IL-22 and IL-13 dichotomously induce goblet cells, in which only IL-13 driven goblet cells are associated with NOTCH signaling. We further show that IL-13 induces BMP signalling to act as a negative feedback loop in IL-13 induced tuft cell hyperplasia, an important aspect of type 2 immunity. Together, we show that targeting developmental pathways may be a useful tool to tailor epithelial effector responses that are necessary for immunity to infection.

immunology↗

bioRxiv2020

LSD1 represses a neonatal/reparative gene program in adult intestinal epithelium

Intestinal epithelial homeostasis is maintained by adult intestinal stem cells, which, alongside Paneth cells, appear after birth in the neonatal period. We aimed to identify new regulators of neonatal intestinal epithelial development by testing a small library of epigenetic modifier inhibitors in Paneth cell-skewed organoid cultures. We found that Lysine-specific demethylase 1A (Kdm1a/Lsd1) is absolutely required for Paneth cell differentiation. Lsd1-deficient crypts, devoid of Paneth cells, are still able to form organoids without a requirement of exogenous or endogenous Wnt. Mechanistically, we find that LSD1 represses genes that are normally expressed in fetal and neonatal epithelium. This gene profile is similar to what is seen in repairing epithelium, and indeed, we find that Lsd1-deficient epithelium has superior regenerative capacities after irradiation injury. In summary, we found an important regulator of neonatal intestinal development and identified a druggable target to reprogram intestinal epithelium towards a reparative state.

developmental biology↗