Project description:Tissue inhibitors of metalloproteinases (TIMP) are endogenous inhibitors of matrix metalloproteinases (MMP). While TIMP2 and TIMP3 inhibit MMPs, TIMP3 also inhibits activation of pro-MMP2 whereas TIMP2 promotes it. Here we assessed the differential role of TIMP2 and TIMP3 in renal injury using the unilateral ureteral obstruction model. Gene microarray assay showed that post-obstruction, the lack of TIMP3 had a greater impact on gene expression of intermediate, late injury- and repair-induced transcripts, kidney selective transcripts and solute carriers. Renal injury in TIMP3-/-, but not in TIMP2-/- mice increased expression of collagen type I/III, connective tissue growth factor, transforming growth factor-β and the downstream Smad2/3 pathway. Interestingly, ureteral obstruction markedly increased MMP2 activation in the kidneys of TIMP3-/- mice which was completely blocked in the kidneys of TIMP2-/- mice. These changes are consistent with enhanced renal tubulointerstitial fibrosis in TIMP3-/- and its reduction in TIMP2-/- mice. The activity of tumor necrosis factor-α converting enzyme, caspase-3 and mitogen activated kinases were elevated in the kidneys of TIMP3-/- but not TIMP2-/- mice, suggesting enhanced activation of apoptotic and pathological signaling pathways only in the obstructed kidney of TIMP3-/- mice. Thus, TIMP2 and TIMP3 play differential and contrasting roles in renal injury, TIMP3 protects from damage whereas TIMP2 promotes injury through MMP2 activation. Kidneys from the wild type (WT), TIMP2-/- and TIMP3-/- mice undergoing sham or unilateral ureteral obstruction (UUO) procedures
Project description:Tissue inhibitors of metalloproteinases (TIMP) are endogenous inhibitors of matrix metalloproteinases (MMP). While TIMP2 and TIMP3 inhibit MMPs, TIMP3 also inhibits activation of pro-MMP2 whereas TIMP2 promotes it. Here we assessed the differential role of TIMP2 and TIMP3 in renal injury using the unilateral ureteral obstruction model. Gene microarray assay showed that post-obstruction, the lack of TIMP3 had a greater impact on gene expression of intermediate, late injury- and repair-induced transcripts, kidney selective transcripts and solute carriers. Renal injury in TIMP3-/-, but not in TIMP2-/- mice increased expression of collagen type I/III, connective tissue growth factor, transforming growth factor-β and the downstream Smad2/3 pathway. Interestingly, ureteral obstruction markedly increased MMP2 activation in the kidneys of TIMP3-/- mice which was completely blocked in the kidneys of TIMP2-/- mice. These changes are consistent with enhanced renal tubulointerstitial fibrosis in TIMP3-/- and its reduction in TIMP2-/- mice. The activity of tumor necrosis factor-α converting enzyme, caspase-3 and mitogen activated kinases were elevated in the kidneys of TIMP3-/- but not TIMP2-/- mice, suggesting enhanced activation of apoptotic and pathological signaling pathways only in the obstructed kidney of TIMP3-/- mice. Thus, TIMP2 and TIMP3 play differential and contrasting roles in renal injury, TIMP3 protects from damage whereas TIMP2 promotes injury through MMP2 activation.
Project description:Introgressed variants from other species can be an important source of genetic variation because they may arise rapidly, can include multiple mutations on a single haplotype, and have often been pretested by selection in the species of origin. Although introgressed alleles are generally deleterious, several studies have reported introgression as the source of adaptive alleles-including the rodenticide-resistant variant of Vkorc1 that introgressed from Mus spretus into European populations of Mus musculus domesticus. Here, we conducted bidirectional genome scans to characterize introgressed regions into one wild population of M. spretus from Spain and three wild populations of M. m. domesticus from France, Germany, and Iran. Despite the fact that these species show considerable intrinsic postzygotic reproductive isolation, introgression was observed in all individuals, including in the M. musculus reference genome (GRCm38). Mus spretus individuals had a greater proportion of introgression compared with M. m. domesticus, and within M. m. domesticus, the proportion of introgression decreased with geographic distance from the area of sympatry. Introgression was observed on all autosomes for both species, but not on the X-chromosome in M. m. domesticus, consistent with known X-linked hybrid sterility and inviability genes that have been mapped to the M. spretus X-chromosome. Tract lengths were generally short with a few outliers of up to 2.7 Mb. Interestingly, the longest introgressed tracts were in olfactory receptor regions, and introgressed tracts were significantly enriched for olfactory receptor genes in both species, suggesting that introgression may be a source of functional novelty even between species with high barriers to gene flow.
Project description:Tubulointerstitial injury plays an important role in diabetic nephropathy (DN) progression; however, no reliable urinary molecule has been used to predict tubulointerstitial injury and renal outcome of DN clinically. In this study, based on tubulointerstitial transcriptome, we identified secretory leukocyte peptidase inhibitor (SLPI) as the molecule associated with renal fibrosis and prognosis of DN. In tubular cells, high glucose could upregulate SLPI, which bound with β-catenin and GSK-3β reciprocally, abolished the interaction between β-catenin and GSK-3β, diminished GSK-3β-regulated β-catenin phosphorylation and the subsequent ubiquitination and degradation, thus led to β-catenin signaling activation and renal fibrosis. Db/db mice injected with adenovirus carrying Slpi-3xflag-GFP (Ad-Slpi-GFP) developed β-catenin signaling activation in the proximal tubule, worse albuminuria and tubulointerstitial fibrosis. Conversely, Slpi knockout (KO) mice with STZ-induced DN developed less albuminuria, tubulointerstitial fibrosis and β-catenin signaling activation. Furthermore, clinical studies showed that urinary SLPI protein level (uSLPI/Cr) had significant correlation with intrarenal SLPI mRNA and interstitial fibrosis. In an independent prospective cohort enrolled 711 patients with biopsy proven DN, uSLPI/Cr level was significantly associated with eGFR slope and improved the prediction value of renal outcome. Together, our study identified SLPI as a novel critical regulator for the progression of tubulointerstitial injury, which may be used as an independent risk predictor of DN progression.
Project description:We created a rat renal congestion model and investigated the effect of renal congestion on hemodynamics and molecular mechanisms. The inferior vena cava (IVC) between the renal veins was ligated by suture in male Sprague-Dawley rats to increase upstream IVC pressure and induce congestion in the left kidney only. Left kidney congestion reduced renal blood flow, glomerular filtration rate, and increased renal interstitial hydrostatic pressure. Tubulointerstitial and glomerular injury and medullary thick ascending limb hypoxia were observed only in the congestive kidneys. Molecules related to extracellular matrix expansion, tubular injury, and focal adhesion were upregulated in microarray analysis. Renal decapsulation ameliorated the tubulointerstitial injury. Electron microscopy captured pericyte detachment in the congestive kidneys. Transgelin and platelet-derived growth factor receptors, as indicators of pericyte-myofibroblast transition, were upregulated in the pericytes and the adjacent interstitium. With the compression of the peritubular capillaries and tubules, hypoxia and physical stress induce pericyte detachment, which could result in extracellular matrix expansion and tubular injury in renal congestion.
Project description:BACKGROUND: Long terminal repeat (LTR) retrotransposons make up a large fraction of the typical mammalian genome. They comprise about 8% of the human genome and approximately 10% of the mouse genome. On account of their abundance, LTR retrotransposons are believed to hold major significance for genome structure and function. Recent advances in genome sequencing of a variety of model organisms has provided an unprecedented opportunity to evaluate better the diversity of LTR retrotransposons resident in eukaryotic genomes. RESULTS: Using a new data-mining program, LTR_STRUC, in conjunction with conventional techniques, we have mined the GenBank mouse (Mus musculus) database and the more complete Ensembl mouse dataset for LTR retrotransposons. We report here that the M. musculus genome contains at least 21 separate families of LTR retrotransposons; 13 of these families are described here for the first time. CONCLUSIONS: All families of mouse LTR retrotransposons are members of the gypsy-like superfamily of retroviral-like elements. Several different families of unrelated non-autonomous elements were identified, suggesting that the evolution of non-autonomy may be a common event. High sequence similarity between several LTR retrotransposons identified in this study and those found in distantly-related species suggests that horizontal transfer has been a significant factor in the evolution of mouse LTR retrotransposons.
Project description:Copy number variation is an important dimension of genetic diversity and has implications in development and disease. As an important model organism, the mouse is a prime candidate for copy number variant (CNV) characterization, but this has yet to be completed for a large sample size. Here we report CNV analysis of publicly available, high-density microarray data files for 351 mouse tail samples, including 290 mice that had not been characterized for CNVs previously.We found 9634 putative autosomal CNVs across the samples affecting 6.87% of the mouse reference genome. We find significant differences in the degree of CNV uniqueness (single sample occurrence) and the nature of CNV-gene overlap between wild-caught mice and classical laboratory strains. CNV-gene overlap was associated with lipid metabolism, pheromone response and olfaction compared to immunity, carbohydrate metabolism and amino-acid metabolism for wild-caught mice and classical laboratory strains, respectively. Using two subspecies of wild-caught Mus musculus, we identified putative CNVs unique to those subspecies and show this diversity is better captured by wild-derived laboratory strains than by the classical laboratory strains. A total of 9 genic copy number variable regions (CNVRs) were selected for experimental confirmation by droplet digital PCR (ddPCR).The analysis we present is a comprehensive, genome-wide analysis of CNVs in Mus musculus, which increases the number of known variants in the species and will accelerate the identification of novel variants in future studies.
Project description:House mice (Mus musculus) emit ultrasonic vocalizations (USVs), which are surprisingly complex and have features of bird song, but their functions are not well understood. Previous studies have reported mixed evidence on whether there are sex differences in USV emission, though vocalization rate or other features may depend upon whether potential receivers are of the same or opposite sex. We recorded the USVs of wild-derived adult house mice (F1 of wild-caught Mus musculus musculus), and we compared the vocalizations of males and females in response to a stimulus mouse of the same- or opposite-sex. To detect and quantify vocalizations, we used an algorithm that automatically detects USVs (Automatic Mouse Ultrasound Detector or A-MUD). We found high individual variation in USV emission rates (4 to 2083 elements/10 min trial) and a skewed distribution, with most mice (60%) emitting few (?50) elements. We found no differences in the rates of calling between the sexes overall, but mice of both sexes emitted vocalizations at a higher rate and higher frequencies during opposite- compared to same-sex interactions. We also observed a trend toward higher amplitudes by males when presented with a male compared to a female stimulus. Our results suggest that mice modulate the rate and frequency of vocalizations depending upon the sex of potential receivers.