The COVID-19 pandemic has seen large-scale pathogen genomic sequencing efforts, becoming part of the toolbox for surveillance and epidemic research. This resulted in an unprecedented level of data sharing to open repositories, which has actively supported the identification of SARS-CoV-2 structure, molecular interactions, mutations and variants, and facilitated vaccine development and drug reuse studies and design. The European COVID-19 Data Platform was launched to support this data sharing, and has resulted in the deposition of several million SARS-CoV-2 raw reads.
View Article and Find Full Text PDFGlycogen synthase 1 (GYS1), the rate-limiting enzyme in muscle glycogen synthesis, plays a central role in energy homeostasis and has been proposed as a therapeutic target in multiple glycogen storage diseases. Despite decades of investigation, there are no known potent, selective small-molecule inhibitors of this enzyme. Here, we report the preclinical characterization of MZ-101, a small molecule that potently inhibits GYS1 in vitro and in vivo without inhibiting GYS2, a related isoform essential for synthesizing liver glycogen.
View Article and Find Full Text PDFBackground: Diabetic nephropathy is associated with endothelial dysfunction and oxidative stress, in which the nitric oxide-soluble guanylate cyclase-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway is impaired. We hypothesize that sGC stimulator Compound 1 can enhance NO signaling, reduce proteinuria in a diabetic nephropathy preclinical model with diminished NO bioavailability and increased oxidized sGC. Therefore, we evaluated the effect of sGC stimulator Compound 1 on the renal effect in obese ZSF1 (ZSF1 OB) rats.
View Article and Find Full Text PDFHigh-throughput phenotypic screening is a key driver for the identification of novel chemical matter in drug discovery for challenging targets, especially for those with an unclear mechanism of pathology. For toxic or gain-of-function proteins, small-molecule suppressors are a targeting/therapeutic strategy that has been successfully applied. As with other high-throughput screens, the screening strategy and proper assays are critical for successfully identifying selective suppressors of the target of interest.
View Article and Find Full Text PDFThe mechanism of pathogenesis associated with APOL1 polymorphisms and risk for non-diabetic chronic kidney disease (CKD) is not fully understood. Prior studies have minimized a causal role for the circulating APOL1 protein, thus efforts to understand kidney pathogenesis have focused on APOL1 expressed in renal cells. Of the kidney cells reported to express APOL1, the proximal tubule expression patterns are inconsistent in published reports, and whether APOL1 is synthesized by the proximal tubule or possibly APOL1 protein in the blood is filtered and reabsorbed by the proximal tubule remains unclear.
View Article and Find Full Text PDFLipotoxicity was recently reported in several forms of kidney disease, including focal segmental glomerulosclerosis (FSGS). Susceptibility to FSGS in African Americans is associated with the presence of genetic variants of the Apolipoprotein L1 gene (APOL1) named G1 and G2. If and how endogenous APOL1 may alter mitochondrial function by the modifying cellular lipid metabolism is unknown.
View Article and Find Full Text PDFFibrosis, or the accumulation of extracellular matrix, is a common feature of many chronic diseases. To interrogate core molecular pathways underlying fibrosis, we cross-examine human primary cells from various tissues treated with TGF-β, as well as kidney and liver fibrosis models. Transcriptome analyses reveal that genes involved in fatty acid oxidation are significantly perturbed.
View Article and Find Full Text PDFBackground: Apolipoprotein L1, APOL1, is a trypanosome lytic factor present in human and certain other primates. APOL1 gene variants, present in individuals of recent sub-Saharan African descent, increase risk for glomerular disease and associate with the disease progression, but the molecular mechanisms have not been defined.
Objectives: We focus on the mechanism how APOL1 variant proteins enhance podocyte injury in the stressed kidney.
Metabolic dysregulation and mitochondrial dysfunction are important features of acute and chronic tissue injury across species, and human genetics and preclinical data suggest that the master metabolic regulator 5'-adenosine monophosphate-activated protein kinase (AMPK) may be an effective therapeutic target for chronic kidney disease (CKD). We have recently disclosed a pan-AMPK activator, MK-8722, that was shown to have beneficial effects in preclinical models. In this study we investigated the effects of MK-8722 in a progressive rat model of diabetic nephropathy to determine whether activation of AMPK would be of therapeutic benefit.
View Article and Find Full Text PDFThe derivatization of pharmaceuticals is a core activity in the discovery and development of new medicines. Late-stage functionalization via modern CH functionalization chemistry has emerged as a powerful technique with which to diversify advanced pharmaceutical intermediates. We report herein a case study in late-stage functionalization towards the development of a new class of indazole-based mineralocorticoid receptor antagonists (MRA).
View Article and Find Full Text PDFApolipoprotein L1 (APOL1) genetic variants G1 and G2, compared to the common allele G0, are major risk factors for non-diabetic kidney disease in African descent populations. APOL1 is a minor protein component of HDL, as well as being expressed in podocytes and vascular cells. Reverse cholesterol transport involves the transport of cholesterol to HDL by cellular ATP-binding cassette; ABCA1 and ABCG1 with subsequent delivery from peripheral tissues to the liver.
View Article and Find Full Text PDFrisk alleles associate with chronic kidney disease in African Americans, but the mechanisms remain to be fully understood. We show that risk alleles activate protein kinase R (PKR) in cultured cells and transgenic mice. This effect is preserved when a premature stop codon is introduced to risk alleles, suggesting that RNA but not protein is required for the effect.
View Article and Find Full Text PDFMultiple integrins have been implicated in modulating renal function. Modulation of integrin function can lead to pathophysiological processes associated with diabetic nephropathy such as alterations in the glomerular filtration barrier and kidney fibrosis. The complexity of these pathophysiological changes implies that multiple integrin subtypes might need to be targeted to ameliorate the progression of renal disease.
View Article and Find Full Text PDFNephrol Dial Transplant
January 2017
APOL1 nephropathies comprise a range of clinical and pathologic syndromes, which can be summarized as focal segmental glomerulosclerosis, in various guises, and arterionephrosclerosis, otherwise known as hypertensive kidney diseases. Current therapies for these conditions may achieve therapeutic targets, reduction in proteinuria and control of blood pressure, respectively, but often fail to halt the progressive decline in kidney function. It appears that current therapies fail to address certain underlying critical pathologic processes that are driven, particularly in podocytes and microvascular cells, by the APOL1 renal risk genetic variants.
View Article and Find Full Text PDFHigh blood pressure is a major risk factor for cardiovascular disease and premature death. However, there is limited knowledge on specific causal genes and pathways. To better understand the genetics of blood pressure, we genotyped 242,296 rare, low-frequency and common genetic variants in up to 192,763 individuals and used ∼155,063 samples for independent replication.
View Article and Find Full Text PDFTwo common missense variants in APOL1 (G1 and G2) have been definitively linked to CKD in black Americans. However, not all individuals with the renal-risk genotype develop CKD, and little is known about how APOL1 variants drive disease. Given the association of APOL1 with HDL particles, which are cleared by the kidney, differences in the level or quality of mutant APOL1‑HDL particles could be causal for disease and might serve as a useful risk stratification marker.
View Article and Find Full Text PDFRationale: Human genetics studies in African Americans have shown a strong correlation between polymorphisms in the ApoL1 gene and chronic kidney disease (CKD). To gain further insight into the etiology of ApoL1-associated kidney diseases, the determination of circulating levels of both wild type as well as ApoL1 variants could be of significant use. To date, antibodies that discriminate between all three ApoL1 variant forms (wild type, G1 and G2) are not available.
View Article and Find Full Text PDFCAF-1 is essential in human cells for the de novo deposition of histones H3 and H4 at the DNA replication fork. Depletion of CAF-1 from various cell lines causes replication fork arrest, activation of the intra-S phase checkpoint, and global defects in chromatin structure. CAF-1 is also involved in coordinating inheritance of states of gene expression and in chromatin assembly following DNA repair.
View Article and Find Full Text PDFColon cancer stem cells (CSC) can be identified with AC133, an antibody that detects an epitope on CD133. However, recent evidence suggests that expression of CD133 is not restricted to CSCs, but is also expressed on differentiated tumor cells. Intriguingly, we observed that detection of the AC133 epitope on the cell surface decreased upon differentiation of CSC in a manner that correlated with loss of clonogenicity.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
October 2003
De novo chromatin assembly maintains histone density on the daughter strands in the wake of the replication fork. The heterotrimer chromatin assembly factor 1 (CAF-1) couples DNA replication to histone deposition in vitro, but is not essential for yeast cell proliferation. Depletion of CAF-1 in human cell lines demonstrated that CAF-1 was required for efficient progression through S-phase.
View Article and Find Full Text PDFTrypanosoma brucei evades the immune system by switching between Variant Surface Glycoprotein (VSG) genes. The active VSG gene is transcribed in one of approximately 20 telomeric expression sites (ESs). It has been postulated that ES polymorphism plays a role in host adaptation.
View Article and Find Full Text PDFThe expression site (ES) loci of Trypanosoma brucei are a valuable model for allelic exclusion and post-transcriptional regulation in a highly divergent eukaryote. ES exist to facilitate the expression and switching of the variant surface glycoproteins (VSG) that are central to trypanosome virulence and persistence. A collection of other potential virulence determinants, known as expression-site-associated-genes (ESAGs), are co-transcribed from the single upstream promoter.
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