The microbiome and acute organ injury: focus on kidneys.

The microbiome of critically ill patients is significantly altered by both effects of the illnesses and clinical interventions provided during intensive care. Studies have shown that manipulating the microbiome can prevent or modulate complications of critical illness in experimental models and preliminary clinical trials. This review aims to discuss general concepts about the microbiome, including mechanisms of modifying acute organ dysfunction. The focus will be on the effects of microbiome modulation during experimental acute kidney injury (excluding septic AKI) and comparison with other experimental acute organ injuries commonly seen in critically ill patients.

Microbiome modulation after severe acute kidney injury accelerates functional recovery and decreases kidney fibrosis.

Targeting gut microbiota has shown promise to prevent experimental acute kidney injury (AKI). However, this has not been studied in relation to accelerating recovery and preventing fibrosis. Here, we found that modifying gut microbiota with an antibiotic administered after severe ischemic kidney injury in mice, particularly with amoxicillin, accelerated recovery. These indices of recovery included increased glomerular filtration rate, diminution of kidney fibrosis, and reduction of kidney profibrotic gene expression. Amoxicillin was found to increase stool Alistipes, Odoribacter and Stomatobaculum species while significantly depleting Holdemanella and Anaeroplasma. Specifically, amoxicillin treatment reduced kidney CD4+T cells, interleukin (IL)-17 +CD4+T cells, and tumor necrosis factor-α double negative T cells while it increased CD8+T cells and PD1+CD8+T cells. Amoxicillin also increased gut lamina propria CD4+T cells while decreasing CD8+T and IL-17+CD4+T cells. Amoxicillin did not accelerate repair in germ-free or CD8-deficient mice, demonstrating microbiome and CD8+T lymphocytes dependence for amoxicillin protective effects. However, amoxicillin remained effective in CD4-deficient mice. Fecal microbiota transplantation from amoxicillin-treated to germ-free mice reduced kidney fibrosis and increased Foxp3+CD8+T cells. Amoxicillin pre-treatment protected mice against kidney bilateral ischemia reperfusion injury but not cisplatin-induced AKI. Thus, modification of gut bacteria with amoxicillin after severe ischemic AKI is a promising novel therapeutic approach to accelerate recovery of kidney function and mitigate the progression of AKI to chronic kidney disease.

Impact of Increased FUT8 Expression on the Extracellular Vesicle Proteome in Prostate Cancer Cells.

Extracellular vesicles (EVs) are involved in intercellular communication, transporting proteins and nucleic acids to proximal and distal regions. There is evidence of glycosylation influencing protein routing into EVs; however, the impact of aberrant cellular glycotransferase expression on EV protein profiles has yet to be evaluated. In this study, we paired extracellular vesicle characterization and quantitative proteomics to determine the systemic impact of altered α(1,6)fucosyltranferase (FUT8) expression on prostate cancer-derived EVs. Our results showed that increased cellular expression of FUT8 could reduce the number of vesicles secreted by prostate cancer cells as well as increase the abundance of proteins associated with cell motility and prostate cancer metastasis. In addition, overexpression of FUT8 resulted in altered glycans on select EV-derived glycoproteins. This study presents the first evidence of altered cellular glycosylation impacting EV protein profiles and provides further rationale for exploring the functional role of glycosylation in EV biogenesis and biology.