Biology subjects

Rajput, S.

Publications and source records attributed to Rajput, S..

7 recordsLinked to original sources

bioRxiv2026

Vitamin D mitigates Inflammatory Bone Loss in Postmenopausal Osteoporosis via modulating the Gut-Immune-Bone axis

Osteoporosis is a prevalent skeletal disorder characterized by deterioration of bone microarchitecture and loss of bone mineral density, leading to increased fracture risk and substantial health and economic burdens, particularly among older adults. Bone remodeling is orchestrated by a complex interplay of systemic and local regulators, among which vitamin D plays a central role in maintaining skeletal homeostasis. Although numerous studies have examined the effects of vitamin D on bone metabolism, outcomes have been inconsistent across populations, dosing regimens, and experimental models. To clarify the net skeletal impact of vitamin D, we investigated its effects in postmenopausal osteoporosis (PMO). Vitamin D (1,25-dihydroxyvitamin D3- active form of vitamin D) supplementation effectively prevented bone loss in ovariectomized mice, at both lower and higher concentrations. Mechanistically, vitamin D promoted osteoclast differentiation in vitro, consistent with its RANKL-dependent pro-osteoclastogenic activity, yet paradoxically conferred bone protection in vivo. This discrepancy was explained by vitamin Ds profound immunomodulatory effects, which reshaped both innate and adaptive immune responses to suppress osteoclast formation and function. Concurrently, vitamin D improved intestinal barrier integrity and restored gut microbial composition, thereby stabilizing the gut-immune-bone axis and reducing pro-resorptive inflammatory signaling. Together, these findings demonstrate that vitamin D prevents bone loss through the coordinated regulation of immune and gut homeostasis, reconciling its apparent pro-resorptive effects in vitro with its overall anti-resorptive outcomes in vivo. This integrated mechanism highlights immune-gut microbial modulation as a key mediator of vitamin D-induced bone preservation and supports the development of vitamin D as an immunotherapeutic adjunct for the prevention and management of PMO. Altogether, our findings for the first time dissect the paradox surrounding the osteoprotective property of vitamin D supplementation. O_FIG O_LINKSMALLFIG WIDTH=186 HEIGHT=200 SRC="FIGDIR/small/735433v1_ufig1.gif" ALT="Figure 1"> View larger version (73K): org.highwire.dtl.DTLVardef@1550497org.highwire.dtl.DTLVardef@a06ab4org.highwire.dtl.DTLVardef@1bd55e5org.highwire.dtl.DTLVardef@1526acd_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphical Abstract:C_FLOATNO Vitamin D strengthens intestinal barrier integrity and restores gut microbial composition, which stabilizes the gut-bone axis and suppresses pro-resorptive inflammatory signaling. Vitamin D enhances osteoclastogenesis both directly and through ILC3- and Th17-mediated pathways, while inhibiting osteoclastogenesis via Treg- and Breg-dependent mechanisms. In circulation, vitamin D maintains the homeostasis between IL-10 and IL-17 cytokines. Collectively, these results indicate that vitamin D helps prevent bone loss by orchestrating the immune system and maintaining gut homeostasis. C_FIG

immunology↗

bioRxiv2026

Structural Lung Remodeling Precedes Functional Decline After Chronic Smoldering Douglas Fir Smoke Exposure in Apoe-/- Mice

Wildland firefighters experience repeated exposure to wildfire smoke, yet the pathophysiological mechanisms underlying chronic inhalation injury remain poorly understood. Although prior studies report parenchymal destruction following prolonged woodsmoke exposure, the temporal relationship between molecular, structural, and functional decline following inhalation of smoke from needles/leaves remains unclear. To address this gap, we characterized coordinated changes in lung structure, function, and underlying molecular disruptions using a dosimetry-based murine model approximating 7-14 years of firefighter service. Male apolipoprotein E-deficient mice were exposed to smoldering Douglas fir needle smoke (40 mg/m3, 2 h/day, 5 days/week) for 8 or 16 weeks. Immunofluorescence analyses revealed an early elastolytic response at 8 weeks, with increased neutrophil elastases and matrix metalloproteinases-9 and -12, accompanied by elevated surfactant protein-D, compared to air controls. These changes were resolved by 16 weeks despite progressive tissue injury. Airspace enlargement was evident at 8 weeks, progressed by 16 weeks, and included increased alveolar blunting and septal wall thickening at the later time point. Cleaved caspase-3 was elevated at 16 weeks, indicative of advanced parenchymal damage and apoptosis. Epithelial tight-junction protein ZO-1 intensity was reduced at both evaluation points, whereas the epithelial-to-mesenchymal marker N-cadherin remained undetectable in the alveolar epithelium. Functional impairment as evident by increased static compliance and upward shifts in pressure-volume curves was only significant after 16 weeks of exposure. Findings indicate that molecular and structural injury of tissue destruction preceded measurable functional decline, underscoring the need for early biomarkers to identify smoke-induced lung injury in wildland firefighters before function loss occurs.

physiology↗

bioRxiv2025

Preclinical immunogenicity of the LP.8.1-adapted BNT162b2 COVID-19 vaccine

SARS-CoV-2 evolution toward antigenically distinct lineages drives escape from host immunity. JN.1 lineage derivatives have recently dominated the global epidemiologic landscape. In preclinical models, an LP.8.1-adapted BNT162b2 vaccine elicited higher serum neutralizing antibody responses against contemporary, circulating JN.1 sublineages, including the currently dominant XFG, as compared to JN.1-, KP.2- and XEC-adapted vaccines. These findings supported the selection of an LP.8.1-adapted vaccine for the composition of the 2025-26 COVID-19 vaccine formula.

immunology↗

bioRxiv2025

Deoxycholic acid (DCA) alleviates LPS-induced Inflammatory Bone Loss via modulating the Gut-Bone homeostasis

Osteoporosis and other forms of inflammatory bone loss are marked by disrupted bone remodelling resulting from an imbalance between osteoclast-mediated bone resorption and osteoblast-driven bone formation. This imbalance is often exacerbated by chronic inflammation and gut microbiota dysbiosis. Recently, attention has turned to gut-associated metabolites (GAMs) such as secondary bile acids, particularly deoxycholic acid (DCA), which act as immunomodulators influencing both systemic inflammation and bone metabolism. In this study, we investigated the role of DCA in inflammatory bone loss using an in vivo model, with a focus on osteoblast and osteoclast function, gut barrier integrity, and gut-microbiota diversity. DCA administration significantly suppressed osteoclastogenesis along with enhancing osteoblastogenesis, indicating its dual regulatory role in bone remodelling. Furthermore, DCA treatment enhanced gut integrity, reversed dysbiosis and reduced systemic inflammation by downregulating osteoclastogenic cytokines (TNF-, IL-6, IL-17, RANKL, etc.). These findings suggest that DCA mitigates LPS-induced inflammatory bone loss through a multifaceted mechanism involving direct effects on bone cells and restoration of gut integrity and homeostasis. Our results highlight the therapeutic potential of targeting the gut microbiota-derived bile acid pathway, particularly DCA, as a novel strategy for managing osteoporosis and other inflammatory bone disorders. O_FIG O_LINKSMALLFIG WIDTH=131 HEIGHT=200 SRC="FIGDIR/small/678724v1_ufig1.gif" ALT="Figure 1"> View larger version (46K): org.highwire.dtl.DTLVardef@1702fddorg.highwire.dtl.DTLVardef@568b38org.highwire.dtl.DTLVardef@1ce463aorg.highwire.dtl.DTLVardef@164a04d_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOFigure 9.C_FLOATNO Graphical Abstract. Secondary bile acids act via FXR and TGR5 receptors on osteoclast and osteoblast cells and thereby regulate bone remodelling. C_FIG

cell biology↗

bioRxiv2024

Immunologic and Biophysical Features of the BNT162b2 JN.1- and KP.2-Adapted COVID-19 Vaccines

Vaccines remain a vital public health tool to reduce the burden of COVID-19. COVID-19 vaccines that are more closely matched to circulating SARS-CoV-2 lineages elicit more potent and relevant immune responses that translate to improved real-world vaccine effectiveness. The rise in prevalence of the Omicron JN.1 lineage, and subsequent derivative sublineages such as KP.2 and KP.3, coincided with reduced neutralizing activity and effectiveness of Omicron XBB.1.5-adapted vaccines. Here, we characterized the biophysical and immunologic attributes of BNT162b2 JN.1- and KP.2-adapted mRNA vaccine-encoded spike (S) protein immunogens. Biophysical interrogations of S revealed the structural consequences of hallmark amino acid substitutions and a potential molecular mechanism of immune escape employed by JN.1 and KP.2. The vaccine candidates were evaluated for their immunogenicity when administered as fourth or fifth doses in BNT162b2-experienced mice or as a primary series in naive mice. In both vaccine-experienced and naive settings, JN.1- and KP.2-adapted vaccines conferred improved neutralizing responses over the BNT162b2 XBB.1.5 vaccine against a broad panel of emerging JN.1 sublineages, including the predominant KP.3.1.1 and emerging XEC lineages. Antigenic mapping of neutralizing responses indicated greater antigenic overlap of JN.1- and KP.2-adapted vaccine responses with currently circulating sublineages compared to an XBB.1.5-adapted vaccine. CD4+ and CD8+ T cell responses were generally conserved across all three vaccines. Together, the data support the selection of JN.1- or KP.2-adapted vaccines for the 2024-25 COVID-19 vaccine formula. ONE-SENTENCE SUMMARYThe Omicron JN.1- and KP.2-adapted BNT162b2 mRNA vaccines encoding prefusion S proteins elicit similar preclinical neutralizing antibody responses against circulating JN.1 sublineage pseudoviruses that are more potent than those elicited by past iterations of BNT162b2 licensed vaccines, thus demonstrating the importance of annual strain changes to the COVID-19 vaccine.

immunology↗

bioRxiv2023

In Vitro Culture Alters Cell Lineage Composition and Cellular Metabolism of Bovine Blastocyst

Profiling transcriptome at single cell level of bovine blastocysts derived in vivo (IVV), in vitro from conventional culture medium (IVC), and reduced nutrient culture medium (IVR) has enabled us to reveal cell lineage segregation, during which forming inner cell mass (ICM), trophectoderm (TE), and an undefined population of transitional cells. Only IVV embryos had well-defined ICM, indicating in vitro culture may delay the first cell fate commitment to ICM. Differences between IVV, IVC and IVR embryos were mainly contributed by ICM and transitional cells. Pathway analysis by using the differentially expressed genes of these non-TE cells between groups pointed to highly active metabolic and biosynthetic processes, with reduced cellular signaling and membrane transport in IVC embryos, which may lead to reduced developmental potential. IVR embryos had lower activities in metabolic and biosynthetic processes, but increased cellular signaling and membrane transport, suggesting these cellular mechanisms may contribute to the improved blastocyst development compared to IVC embryos. However, the IVR embryos had compromised development when compared to IVV embryos with notably over-active membrane transport activities that led to impaired ion homeostasis. Summary StatementSingle-cell transcriptomic analysis of bovine blastocysts produced in vivo, and in vitro in conventional and reduced nutrient conditions reveals the effect of culture environments on embryo developmental potential.

developmental biology↗

bioRxiv2019

A Priori Activation of Apoptosis Pathways of Tumor (AAAPT) Technology: Development of Targeted Apoptosis Initiators for Cancer Treatment.

Cancer cells develop tactics to circumvent the interventions by desensitizing themselves to interventions. The principle routes of desensitization include a) activation of survival pathways (e.g. NF-kB, PARP) and b) downregulation of cell death pathways (e.g. CD95/CD95L). As a result, it requires high therapeutic dose to achieve tumor regression which, in turn damages normal cells through the collateral damaging effects. Methods are needed to sensitize the low and non-responsive resistant tumor cells including cancer stem cells (CSCs) in order to evoke a better response from the current treatments. Current treatments including chemotherapy can induce cell death only in bulk cancer cells sparing CSCs and cancer resistant cells (CRCs) which are shown to be responsible for high recurrence of disease and low patient survival. Here, we report several novel tumor targeted sensitizers derived from the natural Vitamin E analogue (AMP-001-003). The drug design is based on a novel concept "A priori activation of apoptosis pathways of tumor technology (AAAPT) which is designed to activate specific cell death pathways and inhibit survival pathways simultaneously. Our results indicate that AMP-001-003 sensitize various types of cancer cells including MDA-MB-231 (triple negative breast cancer), PC3 (prostate cancer) and A543 (ling cancer) cells resulting in reducing the IC-50 of doxorubicin in vitro. At higher dose, AMP-001 acts as an anti-tumor agent on its own. The synergy between AMP-001 and doxorubicin could pave a new pathway to use AMP-001 as a neoadjuvant to chemotherapy to achieve a better efficacy and reduced off-target toxicity by the current treatments. Summary StatementA Priori Activation of Apoptosis Pathways of Tumor often referred to as "AAAPT" is a novel targeted tumor sensitizing technology which synergizes with chemotherapy to enhance the treatment efficacy.

cancer biology↗