Biology subjects

Crowley, S. D.

Publications and source records attributed to Crowley, S. D..

4 recordsLinked to original sources

bioRxiv2021

Ferroptotic stress promotes the accumulation of pro-inflammatory proximal tubular cells in maladaptive renal repair

Overwhelming lipid peroxidation induces ferroptotic stress and ferroptosis, a non-apoptotic form of regulated cell death that has been implicated in maladaptive renal repair in mice and humans. Using single-cell transcriptomic and mouse genetic approaches, we show that proximal tubular (PT) cells develop a molecularly distinct, pro-inflammatory state following injury. While these inflammatory PT cells transiently appear after mild injury and return to their original state without inducing fibrosis, they accumulate and contribute to persistent inflammation after severe injury. This transient inflammatory PT state significantly downregulates glutathione metabolism genes, making them vulnerable to ferroptotic stress. Genetic induction of high ferroptotic stress in these cells after mild injury leads to the accumulation of the inflammatory PT cells, enhancing inflammation and fibrosis. Our study broadens the roles of ferroptotic stress from being a trigger of regulated cell death to include the promotion and accumulation of proinflammatory cells that underlie maladaptive repair.

cell biology↗

bioRxiv2021

Th17 immunity in the colon is controlled by two novel subsets of colon-specific mononuclear phagocytes

Intestinal immunity is coordinated by specialized mononuclear phagocyte populations, constituted by a diversity of cell subsets. Although the cell subsets constituting the mononuclear phagocyte network are thought to be similar in both small and large intestine, these organs have distinct anatomy, microbial composition, and immunological demands. Whether these distinctions demand organ-specific mononuclear phagocyte populations with dedicated organ-specific roles in immunity are unknown. Here we implement a new strategy to subset murine intestinal mononuclear phagocytes and identify two novel subsets which are colon-specific: a macrophage subset and a Th17-inducing dendritic cell (DC) subset. Colon-specific DCs and macrophages co-expressed CD24 and CD14, and surprisingly, both were dependent on the transcription factor IRF4. Novel IRF4-dependent CD14+CD24+ macrophages were markedly distinct from conventional macrophages and failed to express classical markers including CX3CR1, CD64 and CD88, and surprisingly expressed little IL-10, which was otherwise robustly expressed by all other intestinal macrophages. We further found that colon-specific CD14+CD24+ mononuclear phagocytes were essential for Th17 immunity in the colon, and provide definitive evidence that colon and small intestine have distinct antigen presenting cell requirements for Th17 immunity. Our findings reveal unappreciated organ-specific diversity of intestine-resident mononuclear phagocytes and organ-specific requirements for Th17 immunity.

immunology↗

bioRxiv2020

Annexin A1 tripeptide mimetic increases sirtuin-3 to augment mitochondrial function and limit ischemic kidney injury

BackgroundAcute kidney injury (AKI) is one of the most common organ failures following surgery. We have developed a tripeptide mimetic (ANXA1sp) of the parent annexin A1 molecule that shows promise as an organ protectant limiting cellular stress; however, its potential as a kidney protective agent remains unexplored, and its mechanism of action is poorly understood. Our hypothesis was that ANXA1sp would limit kidney injury and improve mitochondrial function following surgical ischemic kidney injury. MethodsIn blinded fashion, wildtype mice were assigned to receive vehicle control or experimental drug (ANXA1sp) 1 hour prior to and 1 hour after kidney vascular clamping. Our primary outcome was assessment of kidney injury and function by measurement of serum creatinine and blood urea nitrogen (BUN) and histologic injury scoring of kidney tissue sections. Immunofluorescence microscopy, real-time PCR and western blot were used to assess cell death, oxidative stress, and mitochondrial biomarkers. An in vitro model of oxygen-glucose deprivation in immortalized kidney tubule cells was used. ResultsANXA1sp given prior to and after ischemic kidney injury abrogated ischemic AKI. ANXA1sp further limited kidney cell death and oxidative stress following ischemia. ANXA1sp significantly improved markers associated with mitochondrial DNA repair and mitochondrial biogenesis. ANXA1sp upregulated expression of the mitochondrial protectant sirtuin-3 (SIRT3) in the mitochondria of kidney tubular cells. Silencing of SIRT3 limited ANXA1sp-mediated protection against hypoxic cell death. ConclusionsANXA1sp limits kidney injury through upregulation of SIRT3 and consequent preservation of mitochondrial function. ANXA1sp holds considerable promise as a perioperative kidney protectant prior to ischemia inducing surgery and/or kidney transplantation.

physiology↗

bioRxiv2019

Yolk-Sac-Derived Macrophages Progressively Expand in the Mouse Kidney with Age

Renal macrophages represent a highly heterogeneous and specialized population of myeloid cells with mixed developmental origins from the yolk-sac and hematopoietic stem cells (HSC). They promote both injury and repair by regulating inflammation, angiogenesis, and tissue remodeling. Recent reports highlight differential roles for ontogenically distinct renal macrophage populations in disease. However, little is known about how these populations change over time in normal, uninjured kidneys. Prior reports demonstrated a high proportion of HSC-derived macrophages in the young adult kidney. Unexpectedly, using genetic fate-mapping and parabiosis studies, we find that yolk-sac-derived macrophages progressively expand in number with age and become a major contributor to the renal macrophage population in older mice. This chronological shift in macrophage composition involves cellular proliferation and recruitment from circulating progenitors and may contribute to the distinct immune responses, limited reparative capacity, and increased disease susceptibility of kidneys in the elderly population.

immunology↗