👤 Sonisha A Warren

This study presents the phylogenetic and antimicrobial susceptibility characterization of Mycobacterium monacense, a rare nontuberculous mycobacterium (NTM), cultured from clinical extrapulmonary samples. Eight Mycobacterium monacense isolates were identified between 2019 and 2023 in the Western Cape province of South Africa. Whole-genome sequencing (WGS) was applied to assess phylogenetic relatedness, identify virulence factors, and characterize the resistome of the isolates. Antimicrobial susceptibility testing (AST) was performed using the GenoType NTM-DR line probe assay (LPA), Sensititre minimum inhibitory concentrations (MIC) plates, and the proportional method based on critical concentrations. Spatial distribution of cases was mapped using ArcGIS software. Spatiotemporal distribution patterns indicated the presence of circulating clones confined within specific geographical areas. Plasmids coding for ferredoxin and cytochrome P450 genes were identified in one cluster, which notably lacked the chromosomal mbtH gene involved in siderophore biosynthesis for iron acquisition. In contrast, isolates grouped in a second cluster harbored the mbtH chromosomal gene but lacked these plasmid-associated elements. LPA and broth microdilution showed that all Mycobacterium monacense isolates were susceptible to aminoglycosides, fluoroquinolones, and macrolides, but generally exhibited elevated MICs against β-lactam antibiotics. Phenotypic AST indicated that drugs commonly used to treat Mycobacterium tuberculosis complex (MTBC), namely bedaquiline, linezolid, and rifampicin, are effective against Mycobacterium monacense. Mycobacterium monacense in extrapulmonary cultures accentuates the need for improved diagnostics and enhanced clinical awareness of infections with rare NTM. WGS highlights the potential significance provided by plasmid-encoded genes. Current treatment regimens for MTBC exhibit therapeutic efficacy against Mycobacterium monacense isolates. Show less

The majority of pregnancy loss in ruminants occurs during the first two months of gestation, and a failure in placenta development is a major cause of pregnancy loss in cattle after day 20. Gaining a cell-type level understanding of normal placental development is essential for uncovering how this critical organ, responsible for nutrient exchange, gas transfer, and waste removal, fails during pregnancy loss. This study integrated single-cell RNA sequencing (scRNA-seq) from sheep and cattle during early placental development. Nineteen distinct cell populations were identified across species, with mesenchymal, epithelial, and trophoblast cells showing largely conserved expression profiles. Interestingly, two trophoblast clusters were unique to cattle, with one expressing IFNT2 (uninucleate) and another expressing CSH2 and PAG17 (binucleate). Genes associated with epithelial-to-mesenchymal transition (EMT), such as SNAI1, SNAI2, ZEB1, VIM, CDH1, and CLDN4, showed dynamic and prominent expression patterns in trophoblasts. Pseudotime and cell-cell signaling analyses supported the occurrence of EMT in uninucleate trophoblasts. Gene ontology comparisons revealed similarities between ruminant and human extravillous trophoblasts, suggesting conserved EMT across placental types. Collectively, these findings highlight EMT as a potentially critical process in early ruminant placentation. Show less

The coordination between epithelial progenitors and their mesenchymal niche is critical for organogenesis and repair, yet the mechanisms governing their competitive interactions remain unclear. Here, we reveal a paradigm of tissue-scale fitness sensing in the lung, where mesenchymal Yap levels antagonize epithelial Yap levels to dictate epithelial stem cell fate. We show that reduced fitness in alveolar fibroblasts (AF1s) via Yap/Taz or Myc deletion leads to their apoptotic elimination and a collapse of the alveolar stem cell niche. This niche collapse triggers a pathological competitive response from the epithelium, which undergoes aberrant bronchiolization that phenocopies human pulmonary fibrosis. Mechanistically, we uncovered a molecular switch that controls mesenchymal fate. During development and fibrosis resolution, Snail1/2 sequesters Yap/Taz to drive an adipogenic program, generating niche-supportive AF1s. Conversely, Yap/Taz-TEAD-Myc binding instructs a myogenic, pro-fibrotic program. Our findings demonstrate that inter-tissue cell competition, governed by a Snail/Yap rheostat, orchestrates lung architecture and provides a framework for targeting the mesenchymal niche to treat fibrotic disease. Show less

Anti-inflammatory effects of incretin signaling through the glucagon-like peptide-1 receptor (GLP-1R) and the glucose-dependent insulinotropic polypeptide receptor (GIPR) in mice have been reported. Therefore, we hypothesized that signaling through the endogenous GLP-1R and the GIPR individually decreases allergic airway inflammation and that the combination of GLP-1R and GIPR signaling together additively inhibits allergen-induced lung and airway inflammation. WT (C57BL/6J), GLP-1R knockout (KO), GIPR KO, and GLP-1R/GIPR double KO (DKO) mice were challenged intranasally with Alternaria alternata extract (Alt-Ext) or vehicle to evaluate the impact of signaling through these receptors on the innate allergen-induced inflammatory response that is primarily driven by group 2 innate lymphoid cells (ILC2). Alt-Ext-induced IL-33 release in the bronchoalveolar lavage fluid (BALF) was not different between the mouse strains, but thymic stromal lymphopoietin (TSLP) was significantly increased in GLP-1R/GIPR DKO mice challenged with Alt-Ext compared to the other strains. Furthermore, Alt-Ext-induced protein expression of IL-5, IL-13, CCL11, and CCL24 in the lung homogenates, the number of eosinophils, lymphocytes, and neutrophils in the BALF, and the number of lung GATA3+ ILC2 were significantly increased in GLP-1R/GIPR DKO mice compared to the other 3 strains. Furthermore, ICAM-1 expression on lung epithelial cells was increased in GLP-1R/GIPR DKO mice challenged with Alt-Ext compared to the other 3 strains. Deficiency of both GLP-1R and GIPR signaling together increased TSLP release, ILC2 activation, and early type 2 innate immune responses to aeroallergen exposure. Combined GLP-1R and GIPR signaling should be explored for the treatment of asthma. Show less

Genome-wide association studies (GWAS) have identified >250 loci for body mass index (BMI), implicating pathways related to neuronal biology. Most GWAS loci represent clusters of common, noncoding variants from which pinpointing causal genes remains challenging. Here we combined data from 718,734 individuals to discover rare and low-frequency (minor allele frequency (MAF) < 5%) coding variants associated with BMI. We identified 14 coding variants in 13 genes, of which 8 variants were in genes (ZBTB7B, ACHE, RAPGEF3, RAB21, ZFHX3, ENTPD6, ZFR2 and ZNF169) newly implicated in human obesity, 2 variants were in genes (MC4R and KSR2) previously observed to be mutated in extreme obesity and 2 variants were in GIPR. The effect sizes of rare variants are ~10 times larger than those of common variants, with the largest effect observed in carriers of an MC4R mutation introducing a stop codon (p.Tyr35Ter, MAF = 0.01%), who weighed ~7 kg more than non-carriers. Pathway analyses based on the variants associated with BMI confirm enrichment of neuronal genes and provide new evidence for adipocyte and energy expenditure biology, widening the potential of genetically supported therapeutic targets in obesity. Show less

We screened variants on an exome-focused genotyping array in >300,000 participants (replication in >280,000 participants) and identified 444 independent variants in 250 loci significantly associated with total cholesterol (TC), high-density-lipoprotein cholesterol (HDL-C), low-density-lipoprotein cholesterol (LDL-C), and/or triglycerides (TG). At two loci (JAK2 and A1CF), experimental analysis in mice showed lipid changes consistent with the human data. We also found that: (i) beta-thalassemia trait carriers displayed lower TC and were protected from coronary artery disease (CAD); (ii) excluding the CETP locus, there was not a predictable relationship between plasma HDL-C and risk for age-related macular degeneration; (iii) only some mechanisms of lowering LDL-C appeared to increase risk for type 2 diabetes (T2D); and (iv) TG-lowering alleles involved in hepatic production of TG-rich lipoproteins (TM6SF2 and PNPLA3) tracked with higher liver fat, higher risk for T2D, and lower risk for CAD, whereas TG-lowering alleles involved in peripheral lipolysis (LPL and ANGPTL4) had no effect on liver fat but decreased risks for both T2D and CAD. Show less

Atrial natriuretic factor (ANF) is abundantly expressed in atrial cardiomyocytes throughout ontogeny and in ventricular cardiomyocytes in the developing heart. However, during cardiac failure and hypertrophy, ANF expression can reappear in adult ventricular cardiomyocytes. The transcription factor Nkx2-5 is one of the major transactivators of the ANF gene in the developing heart. We identified Nkx2-5 binding at three 5' regulatory elements (kb -34, -31, and -21) and at the proximal ANF promoter by ChIP assay using neonatal mouse cardiomyocytes. 3C analysis revealed close proximity between the distal elements and the promoter region. A 5.8-kb fragment consisting of these elements transactivated a reporter gene in vivo recapitulating endogenous ANF expression, which was markedly reduced in tamoxifen-inducible Nkx2-5 gene knockout mice. However, expression of a reporter gene was increased and expanded toward the outer compact layer in the absence of the transcription repressor Hey2, similar to endogenous ANF expression. Functional Nkx2-5 and Hey2 binding sites separated by 59 bp were identified in the -34 kb element in neonatal cardiomyocytes. In adult hearts, this fragment did not respond to pressure overload, and ANF was induced in the absence of Nkx2-5. These results demonstrate that Nkx2-5 and its responsive cis-regulatory DNA elements are essential for ANF expression selectively in the developing heart. Show less