Fiset, P. O. | bioRxiv Science

bioRxiv2024

Mouse nephron formation is impaired by moderate-dose arsenical exposure

BackgroundArsenic is a naturally occurring toxicant and industrial byproduct with significant health risks. Globally, millions of people are exposed to arsenic concentrations that exceed the World Health Organizations recommended limit of 10 g/L. Chronic arsenic exposure is linked to an increased risk of chronic kidney disease (CKD); however, the effects of arsenic exposure on kidney development remain unclear. Eukaryotes methylate inorganic arsenic (iAsIII) using the enzyme arsenic 3 methyltransferase (As3mt), that converts it to methylated intermediates, mono and dimethyl arsonous acid (MMAIII and DMAIII), and mono and dimethyl arsonic acid (MMAV and DMAV). We hypothesized that arsenicals exposure during mouse kidney development impairs nephron formation. MethodsCultured mouse embryonic kidney explants were treated with inorganic arsenite (iAsIII), MMAIII, MMAV, and DMAV. Female mice harboring a humanized version of AS3MT and wild-type mice with murine As3mt were exposed to iAsIII throughout gestation and weaning and their offspring were analyzed for kidney defects. ResultsInorganic arsenic, iAsIII (200 g/L), inhibited ureteric bud branching morphogenesis and growth of mouse kidneys at embryonic day 11.5 (E11.5) and E12.5, but not at E13.5. MMAIII, but not MMAV or DMAV, impaired ureteric bud branching and kidney explant growth. Additionally, iAsIII exposure increased apoptosis in the metanephric mesenchyme of E11.5 explants and decreased Gdnf transcription, which may explain the impairment in ureteric bud branching. Humanized mouse pups exposed to 200 g/L iAsIII in utero, showed a 20% reduction in kidney weight normalized to body weight and a 28% reduction in nephron number, compared to kidneys of wild-type mice. ConclusionExposure to arsenicals during embryonic development impairs ureteric bud branching morphogenesis and decreases nephron endowment, which may predispose to CKD in adulthood.

developmental biology↗

bioRxiv2023

BCG administration promotes the long-term protection afforded by a single-dose intranasal adenovirus-based SARS-CoV-2 vaccine

Despite medical interventions and several approved vaccines, the COVID-19 pandemic is continuing into its third year. Recent publications have explored single-dose intranasal (i.n.) adenovirus-based vaccines as an effective strategy for curbing SARS-CoV-2 in naive animal models. However, the effects of prior immunizations and infections have yet to be considered within these models. Here, we investigate the immunomodulatory effects of Mycobacterium bovis BCG pre-immunization on a subsequent S-protein expressing i.n. Ad vaccination, termed Ad(Spike). We found that Ad(Spike) alone conferred long-term protection from severe SARS-CoV-2 pathology within a mouse model, yet it was unable to limit initial infection 6 months post-vaccination. While i.n. Ad(Spike) retains some protective effect after 6 months, a single administration of BCG-Danish prior to Ad(Spike) vaccination potentiates its ability to control viral replication of the B.1.351 SARS-CoV-2 variant within the respiratory tract. Though BCG-Danish had no effect on the ability of Ad(Spike) to generate and maintain humoral immunity, it promoted the generation of cytotoxic and Th1 responses over suppressive FoxP3+ TREG cells in the lungs of infected mice. These data demonstrate a novel vaccination strategy that may prove useful in limiting future viral pandemics by potentiating the long-term efficacy of next generation mucosal vaccines within the context of the safe and widely distributed BCG vaccine. One sentence summaryBCG enhances anti-SARS-CoV-2 immunity and protection afforded by a novel adenovirus-vectored vaccine.

immunology↗