Biology subjects

Shah, S. N.

Publications and source records attributed to Shah, S. N..

4 recordsLinked to original sources

bioRxiv2022

Cerebrovascular damage caused by the gut microbe-derived uraemic toxin p-cresol sulfate isprevented by blockade of the epidermal growth factor receptor

Circulating levels of the gut microbe/host co-metabolite p-cresol sulfate (pCS) correlate with cerebrovascular event risk in individuals with chronic kidney disease, but whether this relationship is mechanistic is unclear. We hypothesised that pCS would impair function of the blood-brain barrier (BBB), the primary brain-vasculature interface. We report that pCS exposure impairs BBB integrity in human cells in vitro and both acutely and chronically in mice, enhancing tracer extravasation, disrupting barrier-regulating tight junction components and ultimately affecting whole-brain transcriptomic activity. In vitro and in vivo mechanistic studies showed that pCS activated epidermal growth factor receptor (EGFR) signalling, resulting in matrix metalloproteinase mobilisation and BBB damage. Furthermore, blockade of EGFR prevented the permeabilising effects of serum from haemodialysis patients upon cerebromicrovascular endothelia in vitro. Our results define a pathway linking the co- metabolite pCS with BBB damage and suggest targeting the EGFR may mitigate against cerebrovascular damage in CKD.

systems biology↗

bioRxiv2022

Design And Optimization Studies Of Tablet In Tablet Formulation Of Diclofenac And Misoprostol: Application Of Response Surface Methodolgy And Compressional Behaviour Strategy

The present study was aimed to develop compression coated tablets of diclofenac sodium (75mg) in the inner core and misoprostol (200 mg) as the outer shell for the effective treatment of rheumatoid arthritis as this dosing frequency is not available in the market yet. Diclofenac sodium inner tablet was manufactured by wet granulation and its enteric coating was applied by Eudragit L 100-55, Isopropyl Alcohol and Opadry II Blue 85 F205034. While immediate-release misoprostol outer shell was also manufactured by wet granulation and coated by Opadry white and Polyethylene glycol 6000. Design of experiment(R) software was used for formulation design and optimization. Quality attributes such as tablet weight, hardness, disintegration time, percent drug dissolution and assay were performed as per official methods and satisfactory results were reported. Physical and chemical stability of selected formulations was evaluated following the ICH guidelines for accelerated stability testing. The compressional analysis of optimized formulation was performed to check the optimum compression pressure to obtain a stable formulation. Based on satisfactory quality attributes; formulation DF9MF7 was successfully developed as compression coated tablet with calculated shelf life of 4.8years. Compression coated tablets comprising of enteric coated diclofenac sodium as inner core and misoprostol as outer shell were successfully developed by wet granulation.

pharmacology and toxicology↗

bioRxiv2022

A host-gut microbial co-metabolite of aromatic amino acids, p-cresol glucuronide, promotes blood-brain barrier integrity in vivo

PurposeThe sequential activity of gut microbial and host processes can exert a powerful modulatory influence on dietary components, as exemplified by the metabolism of the amino acids tyrosine and phenylalanine to p-cresol by gut microbes, and then to p-cresol glucuronide (pCG) by host enzymes. Although such glucuronide conjugates are classically thought to be biologically inert, there is accumulating evidence that this may not always be the case. We investigated the activity of pCG, studying its interactions with the cerebral vasculature and the brain in vitro and in vivo. MethodsMale C57Bl/6J mice were used to assess blood-brain barrier (BBB) permeability and whole brain transcriptomic changes in response to pCG treatment. Effects were then further explored using the human cerebromicrovascular endothelial cell line hCMEC/D3, assessing paracellular permeability, transendothelial electrical resistance and barrier protein expression. ResultsMice exposed to pCG showed reduced BBB permeability and significant changes in whole brain transcriptome expression. Surprisingly, treatment of hCMEC/D3 cells with pCG had no notable effects until co-administered with bacterial lipopolysaccharide, at which point it was able to prevent the permeabilising effects of endotoxin. Further analysis suggested that pCG acts as an antagonist at the principal lipopolysaccharide receptor TLR4. ConclusionThe amino acid phase II metabolic product pCG is biologically active at the BBB, highlighting the complexity of gut microbe to host communication and the gut-brain axis.

systems biology↗

bioRxiv2021

Immune Correlates of Protection by mRNA-1273 Immunization against SARS-CoV-2 Infection in Nonhuman Primates

Immune correlates of protection can be used as surrogate endpoints for vaccine efficacy. The nonhuman primate (NHP) model of SARS-CoV-2 infection replicates key features of human infection and may be used to define immune correlates of protection following vaccination. Here, NHP received either no vaccine or doses ranging from 0.3 - 100 g of mRNA-1273, a mRNA vaccine encoding the prefusion-stabilized SARS-CoV-2 spike (S-2P) protein encapsulated in a lipid nanoparticle. mRNA-1273 vaccination elicited robust circulating and mucosal antibody responses in a dose-dependent manner. Viral replication was significantly reduced in bronchoalveolar lavages and nasal swabs following SARS-CoV-2 challenge in vaccinated animals and was most strongly correlated with levels of anti-S antibody binding and neutralizing activity. Consistent with antibodies being a correlate of protection, passive transfer of vaccine-induced IgG to naive hamsters was sufficient to mediate protection. Taken together, these data show that mRNA-1273 vaccine-induced humoral immune responses are a mechanistic correlate of protection against SARS-CoV-2 infection in NHP. One-Sentence SummarymRNA-1273 vaccine-induced antibody responses are a mechanistic correlate of protection against SARS-CoV-2 infection in NHP.

immunology↗