Biomedical subjects

Erwin P Bottinger

Publications and source records attributed to Erwin P Bottinger.

11 recordsLinked to original sources

PubMed2025

Large-scale multi-omics analyses in Hispanic/Latino populations identify genes for cardiometabolic traits.

Here, we present a multi-omics study of type 2 diabetes and quantitative blood lipid and lipoprotein traits conducted to date in Hispanic/Latino populations (nmax = 63,184). We conduct a meta-analysis of 16 type 2 diabetes and 19 lipid trait GWAS, identifying 20 genome-wide significant loci for type 2 diabetes, including one novel locus and novel signals at two known loci, based on fine-mapping. We also identify sixty-one genome-wide significant loci across the lipid/lipoprotein traits, including nine novel loci, and novel signals at 19 known loci through fine-mapping. Next, we analyze genetically regulated expression, perform Mendelian randomization, and analyze association with transcriptomic and proteomic measure using multi-omics data from a Hispanic/Latino population. Using this approach, we identify genes linked to type 2 diabetes and lipid/lipoprotein traits, including TMEM205 and NEDD9 for HDL cholesterol, TREH for triglycerides, and ANXA4 for type 2 diabetes.

Female↗

PubMed2006

Essential role of Smad3 in angiotensin II-induced vascular fibrosis.

Angiotensin II (Ang II) plays a pivotal role in vascular fibrosis, which leads to serious complications in hypertension and diabetes. However, the underlying signaling mechanisms are largely unclear. In hypertensive patients, we found that arteriosclerosis was associated with the activation of Smad2/3. This observation was further investigated in vitro by stimulating mouse primary aorta vascular smooth muscle cells (VSMCs) with Ang II. There were several novel findings. First, Ang II was able to activate an early Smad signaling pathway directly at 15 to 30 minutes. This was extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) dependent but transforming growth factor-beta (TGF-beta) independent because Ang II-induced Smad signaling was blocked by addition of ERK1/2 inhibitor and by dominant-negative (DN) ERK1/2 but not by DN-TGF-beta receptor II (TbetaRII) or conditional deletion of TbetaRII. Second, Ang II was also able to activate the late Smad2/3 signaling pathway at 24 hours, which was TGF-beta dependent because it was blocked by the anti-TGF-beta antibody and DN-TbetaRII. Finally, activation of Smad3 but not Smad2 was a key and necessary mechanism of Ang II-induced vascular fibrosis because Ang II induced Smad3/4 promoter activities and collagen matrix expression was abolished in VSMCs null for Smad3 but not Smad2. Thus, we concluded that Ang II induces vascular fibrosis via both TGF-beta-dependent and ERK1/2 MAPK-dependent Smad signaling pathways. Activation of Smad3 but not Smad2 is a key mechanism by which Ang II mediates arteriosclerosis.

Adult↗

PubMed2006

Nephritogenic anti-DNA antibodies regulate gene expression in MRL/lpr mouse glomerular mesangial cells.

OBJECTIVE: Lupus-associated IgG anti-double-stranded DNA antibodies are thought to be pathogenic in the kidney due to cross-reaction with glomerular antigens, leading subsequently to immune complex formation in situ and complement activation. We undertook this study to determine if pathogenic anti-DNA antibodies may also contribute to renal damage by directly influencing mesangial gene expression. METHODS: Complementary DNA microarray gene profiling was performed in primary mesangial cells (derived from lupus-prone MRL/lpr mice) treated with pathogenic, noncomplexed anti-DNA antibodies. Significant gene up-regulation induced by anti-DNA antibodies as determined by microarray analysis was further investigated by real-time polymerase chain reaction and methods to detect the relevant proteins. Induction of proinflammatory genes by pathogenic antibodies was confirmed by comparing gene expression in glomeruli of old versus young MRL/lpr mice, and by antibody injection in vivo. RESULTS: Pathogenic, but not nonpathogenic, antibodies significantly induced a number of transcripts, including CXCL1/KC, LCN2, iNOS, CX3CL1/fractalkine, SERPINA3G, and IkappaBalpha ("marker genes"). Blocking of Fcgamma receptors or using Fcgamma chain-knockout mesangial cells had no effect on the gene regulation effect of the pathogenic antibody R4A, indicating a non-Fc-dependent mechanism. The glomerular expression of these marker genes increased over time with the development of glomerular antibody deposition and active nephritis in MRL/lpr mice. Moreover, injection of R4A into SCID mice in vivo significantly up-regulated glomerular marker gene expression. CONCLUSION: These findings indicate that the renal pathogenicity of anti-DNA antibodies may be attributed in part to their ability to directly modulate gene expression in kidney mesangial cells through both Fc-dependent and non-Fc-dependent mechanisms.

Acute-Phase Proteins↗

PubMed2005

Glomerular expression of transforming growth factor-beta (TGF-beta) isoforms in mice lacking CD2-associated protein.

Mice lacking CD2-associated protein (CD2AP-/-) develop glomerular lesions resembling human focal segmental glomerulosclerosis (FSGS) between 3-4 weeks of age and die approximately 2 weeks later from massive proteinuria and renal failure. The mechanisms involved in the glomerular injury in this model are unclear. In this study, we used laser capture microdissection (LCM) and real-time PCR, and examined expression of TGF-ss isoforms in CD2AP-/- mice at the level of isolated glomeruli. Total RNA yield from cryosections of 30 glomeruli was 10.71 ng (SD, 5.45) in CD2AP+/+ group (n =7), and 4.20 ng (SD, 2.04) in CD2AP-/- group (n =8), p =0.008. Expression of TGF-ss1 mRNA was increased 1.5-fold in the whole kidney (p =0.030), and twofold in isolated CD2AP-/- glomeruli (p =0.026). Whole kidney mRNA of TGF-ss receptor I (RI) and II (RII) was not different in CD2AP-/- and CD2AP+/+ animals, but it was increased in CD2AP-/- glomerular samples by 4.38-fold (p =0.001) and 11.37-fold (p =0.0163), respectively. By using LCM we confirmed increased glomerular expression levels of TGF-ss isoforms previously described by our group in glomeruli isolated by sieving in CD2AP KO mice and underscored the importance of local factors in the development of glomerulosclerosis.

Adaptor Proteins, Signal Transducing↗

PubMed2004

Gene expression pattern in hepatic stem/progenitor cells during rat fetal development using complementary DNA microarrays.

To identify new and differentially expressed genes in rat fetal liver epithelial stem/progenitor cells during their proliferation, lineage commitment, and differentiation, we used a high throughput method-mouse complementary DNA (cDNA) microarrays-for analysis of gene expression. The gene expression pattern of rat hepatic cells was studied during their differentiation in vivo: from embryonic day (ED) 13 until adulthood. The differentially regulated genes were grouped into two clusters: a cluster of up-regulated genes comprised of 281 clones and a cluster of down-regulated genes comprised of 230 members. The expression of the latter increased abruptly between ED 16 and ED 17. Many of the overexpressed genes from the first cluster fall into distinct, differentially expressed functional groups: genes related to development, morphogenesis, and differentiation; calcium- and phospholipid-binding proteins and signal transducers; and cell adhesion, migration, and matrix proteins. Several other functional groups of genes that are initially down-regulated, then increase during development, also emerged: genes related to inflammation, blood coagulation, detoxification, serum proteins, amino acids, lipids, and carbohydrate metabolism. Twenty-eight genes overexpressed in fetal liver that were not detected in adult liver are suggested as potential markers for identification of liver progenitor cells. In conclusion, our data show that the gene expression program of fetal hepatoblasts differs profoundly from that of adult hepatocytes and that it is regulated in a specific manner with a major switch at ED 16 to 17, marking a dramatic change in the gene expression program during the transition of fetal liver progenitor cells from an undifferentiated to a differentiated state. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Aging↗

PubMed2004

Utility of endogenous creatinine clearance as a measure of renal function in mice.

BACKGROUND: The use of endogenous plasma creatinine levels and creatinine clearance as a tool to evaluate renal function in mice has come under scrutiny as prior studies have reported that the Jaffé alkaline picrate method grossly overestimates true plasma creatinine in mice. As members of the NIDDK Animal Models of Diabetic Complications Consortium (AMDCC), we evaluated the performance and feasibility of an alternative high-performance liquid chromatography (HPLC)-based method for standard determination of plasma creatinine and creatinine clearance in mice. Our purpose was to develop a simple method that provides a reliable, reproducible, and sensitive assay for small volumes (<25 microL) of mouse plasma and sera. METHODS: We compared creatinine clearance measured by HPLC with the Jaffé method and HPLC creatinine clearance with inulin clearance [fluoroscein isothiocyanate (FITC) inulin in an osmotic pump implanted in mouse] in C57BL/6J mice. Different groups of mice underwent either one of two protocols. Protocol A included dietary intervention with normal, low salt plus enalapril, or high salt. Protocol B induced diabetes using streptozotocin. RESULTS: First, mean plasma creatinine levels were significantly lower (P < 0.0001) by HPLC (0.128 +/- 0.026 mg/dL) vs. Jaffé (0.4 +/- 0.12 mg/dL) for mice on a normal diet. Urine creatinine concentrations measured by HPLC were 10% lower than by Jaffé (P < 0.01). Second, mean creatinine clearance by HPLC for mice on a normal diet was 255 +/- 68 microL/min. Mice on low salt diet plus enalapril had reduced creatinine clearance (72.8 +/- 24.2 microL/min) while mice on high salt diet had an elevated creatinine clearance (355 +/- 105 microL/min). Third, diabetic mice (19 to 24 weeks of diabetes) exhibited hyperfiltration as creatinine clearance was 524 +/- 214 microL/min whereas nondiabetic age/gender-matched mice showed a mean creatinine clearance of 206 +/- 41 microL/min. Finally, significant correlation was demonstrated for creatinine clearance by HPLC vs. inulin clearance (R= 0.643; P < 0.001). CONCLUSION: HPLC is highly accurate, much more sensitive and specific than the Jaffé method for plasma creatinine measurements in mice. Creatinine clearance in mice measured by HPLC reflects changes in renal function induced by diet and diabetes.

Animals↗

PubMed2003

Transforming growth factor-beta-induced apoptosis is mediated by Smad-dependent expression of GADD45b through p38 activation.

Transforming growth factor-beta (TGF-beta)-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. In this report, we identify GADD45b as an effector of TGF-beta-induced apoptosis. GADD45b has been shown to be a positive mediator of apoptosis induced by certain cytokines and oncogenes. We show that Gadd45b is an immediateearly response gene for TGF-beta and that the proximal Gadd45b promoter is activated by TGF-beta through the action of Smad2, Smad3, and Smad4. We show that ectopic expression of GADD45b in AML12 murine hepatocytes is sufficient to activate p38 and to trigger apoptotic cell death, whereas antisense inhibition of Gadd45b expression blocks TGF-beta-dependent p38 activation and apoptosis. Furthermore, we also show that TGF-beta can activate p38 and induce apoptosis in mouse primary hepatocytes from wild-type mice, but not from Gadd45b-/- mice. All of these findings suggest that GADD45b participates in TGF-beta-induced apoptosis by acting upstream of p38 activation.

Animals↗

PubMed2003

Gene expression analysis on small numbers of invasive cells collected by chemotaxis from primary mammary tumors of the mouse.

BACKGROUND: cDNA microarrays have the potential to identify the genes involved in invasion and metastasis. However, when used with whole tumor tissue, the results average the expression patterns of different cell types. We have combined chemotaxis-based cell collection of the invasive subpopulation of cells within the primary tumor with array-based gene expression analysis to identify the genes necessary for the process of carcinoma cell invasion. RESULTS: Invasive cells were collected from live primary tumors using microneedles containing chemotactic growth factors to mimic chemotactic signals thought to be present in the primary tumor. When used with mammary tumors of rats and mice, carcinoma cells and macrophages constitute the invasive cell population. Microbeads conjugated with monoclonal anti-CD11b (Mac-1alpha) antibodies were used to separate macrophages from carcinoma cells. We utilized PCR-based cDNA amplification from small number of cells and compared it to the quality and complexity of conventionally generated cDNA to determine if amplified cDNA could be used with fidelity for array analysis of this cell population. These techniques showed a very high level of correlation indicating that the PCR based amplification technique yields a cDNA population that resembles, with high fidelity, the original template population present in the small number of cells used to prepare the cDNA for use with the chip. CONCLUSIONS: The specific collection of invasive cells from a primary tumor and the analysis of gene expression in these cells are is now possible. By further comparing the gene expression patterns of cells collected by invasion into microneedles with that of carcinoma cells obtained from the whole primary tumor, the blood, and whole metastatic tumors, genes that contribute to the invasive process in carcinoma cells may be identified.

Animals↗

PubMed2003

Smad3 mediates the TGF-beta-induced contraction of type I collagen gels by mouse embryo fibroblasts.

TGF-beta signals through TGF-beta receptors and Smad proteins. TGF-beta also augments fibroblast-mediated collagen gel contraction, an in vitro model of connective tissue remodeling. To investigate the importance of Smad2 or Smad3 in this augmentation process, embryo-derived fibroblasts from mice lacking expression of Smad2 or Smad3 genes were cast into native type I collagen gels. Fibroblast-populated gels were then released into 0.2% FCS-DMEM alone or with recombinant human TGF-beta1, beta2, beta3, or recombinant rat PDGF-BB. Gel contraction was determined using an image analyzer. All three isoforms of TGF-beta significantly augmented contraction of collagen gels mediated by fibroblasts with genotypes of Smad2 knockout (S2KO), Smad2 wildtype (S2WT), and Smad3 wildtype (S3WT), but not Smad3 knockout (S3KO) mice. PDGF-BB augmented collagen gel contraction by all fibroblast types. These results suggest that expression of Smad3 but not Smad2 may be critical in TGF-beta augmentation of fibroblast-mediated collagen gel contraction. Thus, the Smad3 gene could be a target for blocking contraction of fibrotic tissue induced by TGF-beta.

Animals↗

PubMed2003

Spectrum and range of oxidative stress responses of human lens epithelial cells to H2O2 insult.

PURPOSE: Oxidative stress (OS) is believed to be a major contributor to age-related cataract and other age-related diseases. METHODS: cDNA microarrays were used to identify the spectrum and range of genes with transcript levels that are altered in response to acute H(2)O(2)-induced OS in human lens epithelial (HLE) cells. HLE cells were treated with 50 microM H(2)O(2) for 1 hour in the absence of serum, followed by a return to complete medium. RNAs were prepared from treated and untreated cells at 0, 1, 2, and 8 hours after H(2)O(2) treatment. RESULTS: The data showed 1171 genes that were significantly up- and downregulated in response to H(2)O(2) treatment. Several functional subcategories of genes were identified, including those encoding DNA repair proteins, antioxidant defense enzymes, molecular chaperones, protein biosynthesis enzymes, and trafficking and degradation proteins. Differential expression of selected genes was confirmed at the level of RNA and/or protein. Many of the identified genes (e.g., glutathione S-transferase [MGST2], thioredoxin reductase beta, and peroxiredoxin 2) have been identified as participants in OS responses in the lens and other systems. Some genes induced by OS in the current study (e.g., oxygen regulated protein [ORP150] and heat shock protein [HSP40]) are better known to respond to other forms of stress. Two genes (receptor tyrosine kinase [AXL/ARK] and protein phosphatase 2A) are known to be differentially expressed in cataract. Most of the genes point to a novel pathways associated with OS. CONCLUSIONS: The present data provide a global perspective on those genes that respond to acute OS, point to novel genes and pathways associated with OS, and set the groundwork for understanding the functions of OS-related genes in lens protection and disease.

Apoptosis↗

PubMed2002

Single cell behavior in metastatic primary mammary tumors correlated with gene expression patterns revealed by molecular profiling.

We have developed animal models of breast cancer that allow the direct examination of the behavior of individual green fluorescent protein-expressing carcinoma cells in live nonmetastatic and metastatic primary tumors in situ. We have combined this model with multiphoton microscopy to image differences in cell behavior within the primary tumor. Differences in cell behavior between nonmetastatic and metastatic cells in culture and within live primary tumors were correlated with results from cDNA microarray analyses to identify potentially important genetic determinants for breast cancer invasion and metastasis. Using multiphoton microscopy, we found five major differences in carcinoma cell behavior between the nonmetastatic and metastatic primary breast tumors involving extracellular matrix, cell motility, and chemotaxis. Behavioral differences were correlated with seven categories of molecules that were differentially expressed and related to these behaviors. We have found that extracellular matrix composition, actin nucleation factors, molecules involved in mechanical stability and survival, and cell polarity and chemotaxis showed large and consistent differences in gene expression. We conclude that aligning cell behavior in vivo with patterns of gene expression can lead to new insights into the microenvironment of carcinoma cells in the primary tumor and the molecular mechanisms behind cell behavior.

Adenocarcinoma↗