Biology subjects

Platt, M. P.

Publications and source records attributed to Platt, M. P..

3 recordsLinked to original sources

bioRxiv2023

Hypothalamic thyroid hormone deficiency underlies reversible anorexia in a mammalian hibernator

Mammalian hibernators survive prolonged periods of cold and resource scarcity by temporarily modulating normal physiological functions, but the mechanisms underlying these adaptations are poorly understood. The hibernation cycle of thirteen-lined ground squirrels (Ictidomys tridecemlineatus) lasts for 5-7 months and comprises weeks of hypometabolic, hypothermic torpor interspersed with 24-48-hour periods of an active-like interbout arousal (IBA) state. We show that ground squirrels, who endure the entire hibernation season without food, have negligible hunger during IBAs. These squirrels exhibit reversible inhibition of the hypothalamic feeding center, such that hypothalamic arcuate nucleus neurons exhibit reduced sensitivity to the orexigenic and anorexigenic effects of ghrelin and leptin, respectively. However, hypothalamic infusion of thyroid hormone during an IBA is sufficient to rescue hibernation anorexia. Our results reveal that thyroid hormone deficiency underlies hibernation anorexia and demonstrate the functional flexibility of the hypothalamic feeding center.

physiology↗

bioRxiv2022

A multiomics analysis of direct interkingdom dynamics between influenza A virus and Streptococcus pneumoniae uncovers host-independent changes to bacterial virulence fitness

BackgroundFor almost a century, it has been recognized that influenza A virus (IAV) infection can promote the development of secondary bacterial infections (SBI) mainly caused by Streptococcus pneumoniae (Spn). Recent observations have shown that IAV is able to directly bind to the surface of Spn. To gain a foundational understanding of how direct IAV-Spn interaction alters bacterial biological fitness we employed combinatorial multi-omic and molecular approaches. ResultsHere we show IAV significantly remodels the global transcriptome, proteome and phosphoproteome profiles of Spn independently of host effectors. We identified Spn surface proteins that interact with IAV proteins (hemagglutinin, nucleoprotein, and neuraminidase). In addition, IAV was found to directly modulate expression of Spn virulence determinants such as pneumococcal surface protein A, pneumolysin, and factors associated with antimicrobial resistance among many others. Metabolic pathways were significantly altered leading to changes in Spn growth rate. IAV was also found to drive Spn capsule shedding and the release of pneumococcal surface proteins. Released proteins were found to be involved in evasion of innate immune responses and actively reduced human complement hemolytic and opsonizing activity. IAV also led to phosphorylation changes in Spn proteins associated with metabolism and bacterial virulence. Validation of proteomic data showed significant changes in Spn galactose and glucose metabolism. Furthermore, supplementation with galactose rescued bacterial growth and promoted bacterial invasion, while glucose supplementation led to enhanced pneumolysin production and lung cell apoptosis. ConclusionsHere we demonstrate that IAV can directly modulate Spn biology without the requirement of host effectors and support the notion that inter-kingdom interactions between human viruses and commensal pathobionts can promote bacterial pathogenesis and microbiome dysbiosis.

microbiology↗

bioRxiv2020

The global proteome and phosphoproteome landscape of sepsis-induced kidney injury

Sepsis-induced acute kidney injury (S-AKI) is the most common complication in hospitalized and critically ill patients, highlighted by a rapid decline of kidney function occurring a few hours or days after sepsis onset. Systemic inflammation elicited by microbial infections is believed to lead to kidney damage under immunocompromised conditions. However, while AKI has been recognized as a disease with long-term sequelae, partly due to the associated higher risk of chronic kidney disease (CKD), the understanding of kidney pathophysiology at the molecular level and the global view of dynamic regulations in situ after S-AKI, including transition to CKD, remains limited. Existing studies of S-AKI mainly focus on deriving sepsis biomarkers from body fluids. In the present study, we constructed a mid-severity septic murine model using cecal ligation and puncture (CLP), and examined the temporal changes to the kidney proteome and phosphoproteome at day 2 and day 7 after CLP surgery, corresponding to S-AKI and the transition to CKD, respectively by employing an ultrafast and economical filter-based sample processing method combined with the label-free quantitation approach. Collectively, we identified 2,119 proteins and 2,950 phosphosites through multi-proteomics analyses. Here we denote the pathways that are specifically responsive to S-AKI and its transition to CKD, which include regulation of cell metabolism regulation, oxidative stress, and energy consumption in the diseased kidneys. Our data can serve as an enriched resource for the identification of mechanisms and biomarkers for sepsis-induced kidney diseases.AbbreviationsAKIAcute kidney injuryBADBcl2-associated agonist of cell death proteinCKDChronic kidney diseaseCLPCecal ligation and punctureDAMPsDamage-associated molecular patternsELISAEnzyme-linked immunosorbent assayESCRTEndosomal sorting complexes required for transportFADDFAS-associated death domain proteinFCFold changeFDRFalse discovery rateGOGene OntologyGsdmdGasdermin DICUIntensive care unitKEGGKyoto Encyclopedia of Genes and GenomesLFQLabel-free quantitationNGALNeutrophil gelatinase-associated lipocalin proteinPAMPsPathogen-associated molecular patternsPASPeriodic acid-SchiffPCAPrinciple component analysisS-AKISepsis-induced acute kidney injurySLCSolute carrier proteinsSTrapSuspension TrappingTLRsToll-like receptorsView Full Text

pathology↗