Biology subjects

Alverdy, J. C.

Publications and source records attributed to Alverdy, J. C..

3 recordsLinked to original sources

bioRxiv2026

IL-6R blockade with tocilizumab disrupts pericyte-and tumor cell-driven IL-6/STAT3 signaling, enhancing docetaxel efficacy in ER+ breast cancer

Metastatic breast cancer is a global health concern with a persistently low five-year survival rate. Taxane microtubule stabilizers, including docetaxel (DTX), are the standard of care in various treatment protocols. DTX is used both as a single agent and in combination therapies, with a majority of ER+ breast cancer patients ultimately developing chemoresistance. The mechanisms contributing to chemoresistance involving the tumor microenvironment (TME) have not been fully elucidated. Specifically, the role of vascular cells within the TME, particularly pericytes, is understudied, and their role in promoting chemoresistance remains unknown. Inflammatory cytokines such as interleukin 6 (IL-6) are known to drive drug resistance via activation of the pro-survival JAK/STAT pathway. We found that DTX induced IL-6 secretion of pericytes by at least two-fold compared to vehicle-treated controls in vitro. All tested breast cancer cell lines expressed subunits of the IL-6 receptor (IL-6R) complex, indicating their capacity to respond to JAK/STAT signaling. Conditioned media from DTX-treated pericytes activated STAT3 in ER+ breast cancer cells to levels comparable to recombinant IL-6. Pharmacologic blockade of IL-6 signaling with the IL-6R inhibitor, tocilizumab, reduced DTX-induced STAT3 activation in vitro. Furthermore, combined treatment with tocilizumab and DTX synergistically suppressed the growth of zero-passage patient-derived ER+ breast cancer organoids expressing intact IL-6 signaling. Together, our findings suggest that combining DTX with tocilizumab may revert DTX-induced chemoresistance in ER+ breast cancer patients by inhibiting IL-6-mediated activation of the STAT3 pathway.

cancer biology↗

bioRxiv2026

Post-COVID impairment of memory T cell responses to community-acquired pathogens can be rectified by activating cellular metabolism

Infection rates involving bacterial and viral pathogens have increased precipitously after the COVID-19 pandemic. While it has been speculated that higher infection rates resulted from increased hospitalizations throughout the pandemic or greater use of antibiotics, precisely why rates remain high today has remained unexplained. Mitochondrial dysfunction is known to occur post-COVID and may disrupt immune responses. Within T cells, SARS-CoV-2 infection is linked to low mitochondrial membrane potential, increased mitochondrial apoptosis, and decreased mitochondrial respiration, which together impact cellular activation and function beyond the acute phase of illness. Here, we demonstrate that decreased mitochondrial function in antigen-specific T cells post-COVID may contribute to higher infection susceptibility by metabolically immobilizing T cell memory responses. Using donor-matched peripheral blood samples from 31 COVID-naive individuals who subsequently contracted COVID-19, we tracked how influenza A (IAV), Staphylococcus aureus (SA), and Varicella-zoster virus (VZV) T cell responses were impacted by COVID-19 infection. We found that gene expression linked to T cell activation decreased but mitochondrial redox pathways increased in CD4 memory T cells post-COVID. However, mitochondrial flux and reactive oxygen species production were limited in a plurality of post-COVID memory T cells after stimulation with IAV, SA, and VZV. Furthermore, we found a disordered relationship between memory T cell mobilization of glycolysis, fatty acid metabolism, and oxidative phosphorylation pathways post-COVID which resulted in diminished use of catabolic pathways including glycolysis and fatty acid oxidation in antigen-specific T cells. Modulation of mitochondrial function with metformin and ubiquinol partially rescued the post-COVID decline in T cell catabolism. Collectively, these findings indicate that COVID-19 infection may have lasting effects on inhibiting T cell memory responses to commonly encountered community-acquired pathogens which can be corrected with commonly available medications. This has significant implications for the clinical care of immunologically vulnerable populations in the post-pandemic era.

immunology↗

bioRxiv2020

Peptide YY: a novel Paneth cell antimicrobial peptide that maintains fungal commensalism

Perturbed interactions between the intestinal microbes and host correlate with emergence of fungal virulence. Here we report a previously unknown role for peptide YY (PYY), a described endocrine molecule, as an antimicrobial peptide (AMP) expressed by gut immune epithelial Paneth Cells (PC). PC-PYY differs from other AMPs, including lysozyme, because of limited antibacterial activity, packaging in discrete secretory granules, and selective antifungal activity to virulent hyphae, but not yeast forms of Candida albicans. The latter action is through binding of cationic PC-PYY to the anionic hyphal surface, resulting in membrane disruption and killing. PC-PYY is compartmentalized to surface mucus, which optimizes activity and prevents conversion to endocrine PYY by dipeptidyl peptidase-IV (DPP-IV). We conclude PC-PYY is a unique AMP with selective antifungal activity that maintains gut fungal commensalism. Compromised PC-PYY action from PC dysfunction and/or mucus depletion in ileal Crohns disease may initiate or contribute to disease via fungal pathogenesis. Highlights Paneth Cell PYY (PC-PYY) is an antimicrobial peptide that differs from endocrine-PYY PC-PYY is a selective anti-fungal peptide, targeting the virulent form of C. albicans PC-PYY is separately packaged, retained by mucus, and released by C. albicans hyphae PC-PYY is proposed as essential for maintenance of fungal commensalism in the gut Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY Model for Paneth cell (PC) PYY action and regulation of fungal commensalisms and potential role in the pathogenesis of ileal Crohns Disease (iCD) (A) In a healthy ileum, commensal yeast reside and do not stimulate PYY1-36 release from PCs. (B) Increased virulent hyphae (purple hyphae) results in PYY1-36 release from crypt PCs into the mucus. Hyphae are targeted by PYY1-36 and killed (red hyphae) to manage the increased fungi community in gut. (C) In a diseased ileum such as iCD, hyphal load induces immune activation and increased inflammation through PC dysfunction (gray PCs) and decreased PYY1-36 release or mucus depletion and PC dysfunction. C_FIG_DISPLAY

molecular biology↗