Project description:The lack of Oxalobacter formigenes colonization in the human gut is generally acknowledged as a risk factor for kidney stone formation since this microorganism can play an important role in oxalate homeostasis. Here, we present the genome sequence of OXCC13, a human strain isolated from an individual residing in Germany.
Project description:Kidney stones (KS) are very common, excruciating, and are associated with tremendous healthcare cost, chronic kidney disease (CKD), and end stage renal disease (ESRD). Most KS are composed of calcium oxalate and very small increases in urine oxalate concentration increase the risk for stone formation. Besides its critical role in the pathogenesis of KS, emerging data suggest that disturbed oxalate homeostasis (hyperoxaluria and/or hyperoxalemia) contributes to CKD progression, CKD - and ESRD-associated cardiovascular diseases, progression of cyst growth in autosomal dominant polycystic kidney disease (ADPKD), and delayed graft function & poor renal allograft survival. This emphasizes the urgent need for plasma and urinary oxalate lowering therapies, and enhancing the bowel’s ability to secrete oxalate may effectively do so. We previously identified Oxalobacter formigenes (O. formigenes)-derived factors secreted in its culture conditioned medium (CM) which stimulated oxalate transport by human intestinal Caco2-BBE (C2) cells and reduced urinary oxalate excretion in hyperoxaluric mice by enhancing colonic oxalate secretion. Given their remarkable therapeutic potential, we now identified several proteins belonging to Sel1-like family as the major O. formigenes-derived secreted factors, and we determined the crystal structures for six proteins to better understand their function. Importantly, Sel1-14-derived small peptides P8 & P9 were identified as the major factors, with P8+9 closely recapitulate the CM’s effects, including acting through the oxalate transporters SLC26A2 & SLC26A6 and PKA activation. P8+9 also stimulate oxalate transport by human ileal and colonic organoids, confirming that these peptides work in human tissues. Collectively, the identification of these small peptides provide a great opportunity for developing a peptide-based novel therapeutic for hyperoxalemia, hyperoxaluria, and related disorders, impacting the outcomes of patients suffering from KS, primary hyperoxaluria, CKD, ADPKD, ESRD, and renal transplant recipients.
Project description:Colonization of the intestine with Oxalobacter formigenes reduces urinary oxalate excretion and lowers the risk of forming calcium oxalate kidney stones. Here, we report the genome sequence of Oxalobacter formigenes SSYG-15, a strain isolated from a stool sample from a healthy Chinese boy.
Project description:Oxalobacter formigenes (O. formigenes) is a nonpathogenic, Gram-negative, obligate anaerobic bacterium that commonly inhabits the human gut and degrades oxalate as its major energy and carbon source. Results from a case-controlled study suggested that lack of O. formigenes colonization is a risk factor for recurrent calcium oxalate stone formation. Hence, O. formigenes colonization may prove to be an efficacious method for limiting calcium oxalate stone risk. However, challenges exist in the preparation of O. formigenes as a successful probiotic due to it being an anaerobe with fastidious growth requirements. Here we examine in vitro properties expected of a successful probiotic strain. The data show that the Group 1 O. formigenes strain OxCC13 is sensitive to pH < 5.0, persists in the absence of oxalate, is aerotolerant, and survives for long periods when freeze-dried or mixed with yogurt. These findings highlight the resilience of this O. formigenes strain to some processes and conditions associated with the manufacture, storage and distribution of probiotic strains.