Project description:Gene-level and exon-level analysis of gene expression in MDA-MB-231 cells that stably express control shRNA or integrin α3-targeting shRNA. The laminin-332-binding integrin α3b1 is expressed highly in many breast cancer cells, but its roles in regulating gene expression programs that promote breast cancer progression have not been explored. In order to identify genes that are regulated by α3b1 in human breast cancer cells, we used a lentiviral approach to express an α3-targeting shRNA to suppress integrin α3b1 in MDA-MB-231 cells, and we identified subsequent changes in gene expression and alternate exon useage. We used the Affymetrix Human Exon 1.0 ST platform to analyze biological replicates of MDA-MB-231 cells that were transduced with lentivirus to stably express either control shRNA or α3-targeting shRNA. Array data was processed by Affymetrix Exon Array Computational Tool.
Project description:Integrins are among the most abundant cell surface receptors constituting the principal adhesion receptors for the extracellular matrix (ECM), providing a physical anchor for the cell and triggering multiple intracellular signalling events. Loss-of function mutations of the integrin α3 gene (ITGA3) have been recently disclosed in patients with interstitial lung disease, congenital nephrotic syndrome and junctional epidermolysis bullosa, a multiorgan disorder with fatal outcome. In these patients, the respiratory function is strongly impaired and the kidneys are variably affected, whereas skin fragility is rather mild, has a delayed onset after birth or remains unrecognized, suggesting that integrin α3 differently influences the development and homeostasis of these organs. Here we employed authentic human keratinocytes bearing a naturally occurring integrin α3 loss-of-function mutation as a prototype to characterize the molecular mechanisms launched by the constitutional absence of this integrin subunit. To validate our findings, we generated new cellular models, including an additional ILNEB patient cell line, ITGA3 rescued and knockdown cells. We show that keratinocytes lacking a functional α3 subunit have an activated cellular phenotype with a switch in the pattern of integrin α subunits on the cell surface. These assure spreading and adhesion of epidermal keratinocytes but also drive the migratory phenotype of these cells.
Project description:Integrin dimers α3/β1, α6/β1 and α6/β4 are the mammary epithelial cell receptors for laminins, which are major components of the basement membrane, a specialized extracellular matrix surrounding the mammary epithelium. The roles of specific basement membrane components and their integrin receptors in the regulation of functional gland development have not been analyzed in detail. To investigate the functions of laminin-binding integrins, we obtained mutant mice with mammary luminal cell-specific deficiencies of the α3 and α6 integrin chains generated by the Cre-Lox approach. During pregnancy, mutant mice displayed low levels of luminal progenitor activity and retarded lobulo-alveolar development, whereas their mammary glands seemed to be functional at the onset of lactation. Myoepithelial cell morphology was markedly altered in mutant glands, suggesting cellular compensation mechanisms involving cytoskeleton reorganization. However, lactation was not sustained in mutant mice, and the glands underwent precocious involution. Inactivation of the p53 gene rescued the growth defects but did not restore lactogenesis in mutant mice. This study reveals an essential role for laminin-binding integrins in functional mammary gland development.
Project description:Integrin dimers α3/β1, α6/β1 and α6/β4 are the mammary epithelial cell receptors for laminins, which are major components of the basement membrane, a specialized extracellular matrix surrounding the mammary epithelium. The roles of specific basement membrane components and their integrin receptors in the regulation of functional gland development have not been analyzed in detail. To investigate the functions of laminin-binding integrins, we obtained mutant mice with mammary luminal cell-specific deficiencies of the α3 and α6 integrin chains generated by the Cre-Lox approach. During pregnancy, mutant mice displayed low levels of luminal progenitor activity and retarded lobulo-alveolar development, whereas their mammary glands seemed to be functional at the onset of lactation. Myoepithelial cell morphology was markedly altered in mutant glands, suggesting cellular compensation mechanisms involving cytoskeleton reorganization. However, lactation was not sustained in mutant mice, and the glands underwent precocious involution. Inactivation of the p53 gene rescued the growth defects but did not restore lactogenesis in mutant mice. This study reveals an essential role for laminin-binding integrins in functional mammary gland development.
Project description:Gene-level and exon-level analysis of gene expression in MDA-MB-231 cells that stably express control shRNA or integrin α3-targeting shRNA. The laminin-332-binding integrin α3b1 is expressed highly in many breast cancer cells, but its roles in regulating gene expression programs that promote breast cancer progression have not been explored. In order to identify genes that are regulated by α3b1 in human breast cancer cells, we used a lentiviral approach to express an α3-targeting shRNA to suppress integrin α3b1 in MDA-MB-231 cells, and we identified subsequent changes in gene expression and alternate exon useage.
Project description:A goal of this project is to evaluate the integrin mRNA expression in human neural stem/progenitor cells (hNSPC) using high-throughput sequencing technologies. We found high levels of mRNA expression for the β1, α7, α3, α6, β5, αV, α5, and α9 integrins. This suggests that hNSPCs may express integrin receptors that can bind fibrinogen and laminin proteins.
Project description:Integrin-α3 plays a central role in the interplay of cells, morphogens and ECM, required for proper nephrogenesis, thus adding ITGA3 to the list of CAKUT (congenital anomalies of the kidney and urinary tract)-causing genes.
Project description:COL4A3/A4/A5 mutations have been identified as critical causes of Alport syndrome and other genetic chronic kidney diseases. However, the underlying pathogenesis remains unclear, and specific treatments are lacking. Here, we constructed a transgenic Alport syndrome mouse model by generating a mutation (Col4a3 p.G799R) identified previously from one large Alport syndrome family into mice. We observed that the mutation caused a pathological decrease in intracellular and secreted collagen IV α3α4α5 heterotrimers. The mutant collagen IV α3 chains abnormally accumulated in the endoplasmic reticulum and exhibited defective secretion, leading to persistent endoplasmic reticulum stress in vivo and in vitro. RNA-seq analysis revealed that the MyD88/p38 MAPK pathway plays key roles in mediating subsequent inflammation and apoptosis signaling activation. Treatment with tauroursodeoxycholic acid, a chemical chaperone drug that functions as an endoplasmic reticulum stress inhibitor, effectively suppressed endoplasmic reticulum stress, promoted secretion of the α3 chains, and inhibited the activation of the MyD88/p38 MAPK pathway. Tauroursodeoxycholic acid treatment significantly improved renal function in vivo. These results partly clarified the pathogenesis of renal injuries associated with Alport syndrome, especially in glomeruli, and suggested that tauroursodeoxycholic acid might be useful for the early clinical treatment of Alport syndrome.