There Is Temporal and Spatial Expression of α1 (IV), α2 (IV), α5 (IV), α6 (IV) Collagen Chains and β1 Integrins During the Development of the Basal Lamina in an “In Vitro” Skin Model

Abstract

Temporal and spatial expression of alpha1 (IV), alpha2 (IV), alpha3 (IV), alpha4 (IV), alpha5 (IV), and alpha6 (IV) collagen chains was studied during the formation of the basal lamina in an "in vitro" skin model. A sequential study was performed at 7-d and 14-d cultures (lamina densa absent) and at 28-, 36-, and 56-d cultures (lamina densa present). Expression of beta1, beta4, alpha1, alpha2, alpha3, alpha5, alpha6 integrin subunits and co-localization with collagen IV was studied by regular and laser confocal indirect immunofluorescence microscopy. mRNA expression of alpha2 (IV) and alpha6 (IV) chains was estimated by northern blots. The earliest expression of alpha1 (IV) and alpha2 (IV) collagen chains was noted in 7-d cultures restricted to basal keratinocytes. At 14-d cultures, alpha1 (IV) and alpha2 (IV) chains were noted in basal keratinocytes and as a broad band (10 microm) in the adjacent dermis. At this stage 80% of the alpha2 (IV) mRNA was expressed in the dermis and 20% in the epidermis. At 28-, 36-, and 56-d cultures the alpha1 (IV) and alpha2 (IV) chains were present in a linear distribution at the epidermo-dermal junction and in the upper dermis. The alpha6 (IV) collagen chains were expressed much later at 36-d cultures and the alpha5 (IV) at 56 d, both mostly in a linear distribution but also in the adjacent dermis. Alpha6 (IV) mRNA was demonstrated in the dermis of 36-d cultures. There was co-localization of collagen IV and beta1 integrin subunits in 14-d cultures at the matrix site of keratinocytes. Functional perturbation studies with AIIB2 monoclonal antibody (anti-beta1 subunits) and competitive inhibition with a collagen cyanogen bromide digestion derived fragment (CB3[IV]) that contains the collagen IV ligand for alpha1beta1, alpha2beta1 integrins, altered the pattern of collagen IV deposition.

RETRACTED ARTICLE: Inhibition of Tumor Angiogenesis by Tumstatin: Insights into Signaling Mechanisms and Implications in Cancer Regression

“…Type IV collagen is found normally in the BM, during certain pathological conditions associated with tumor fibrosis, it accumulates in tumor interstitium (4). α1(IV) and α2(IV) collagen chains are most abundant forms of type IV collagen and are widely expressed and co-localized in numerous tissue types, whereas α3-α6 chains show temporal and spatial distribution, and expression in physiological as well as pathological processes (25)(26)(27)(28)(29).…”

Biosynthesis of ?2(IV) and ?1(IV) chains of collagen IV and interactions with matrix metalloproteinase-9

“…To ascertain that single ␣2(IV) chains were detected and not native collagen IV molecules, incubation of the cells with the H22 mAb was carried out without fixation. It has been previously reported that the H22 mAb can recognize trimeric BM collagen IV only in acid-fixed tissues (Fleischmajer et al, 1997;Sado et al, 1995). As shown in Figure 6, a punctate pattern of staining, localized mostly at the cell periphery and at areas of cell-cell contacts, was observed with the H22 mAb (Fig.…”

Superficial Dermal Fibroblasts Enhance Basement Membrane and Epidermal Barrier Formation in Tissue-Engineered Skin: Implications for Treatment of Skin Basement Membrane Disorders

“…Both keratinocytes and fibroblasts contribute to the formation of the basement membrane. [3][4][5] The basement membrane and the underlying dermis play critical roles in the maturation and function of skin by regulating keratinocyte growth and terminal differentiation. The barrier property of the epidermis is due to the presence of tight junctions and lipids, such as ceramides, cholesterol esters, and free fatty acids, which accumulate during epidermal differentiation.…”

“…9,10 Further, recently, our research showed that superficial fibroblasts are antifibrotic, while deep fibroblasts are profibrotic and both differentially remodel collagen-glycosaminoglycan (C-GAG) matrices. 9,10 In addition, compared to superficial wounds, deep dermal wounds were found to express lower amounts of the antifibrotic molecules-decorin, fibromodulin, TGF-b 3 , and Thy-1, but higher TGF-b type II receptors. 11 Furthermore, studies in 2D culture showed that site-matched superficial and deep dermal fibroblasts differ in the production of certain cytokines and in their interactions with keratinocytes; superficial fibroblasts release higher levels of GM-CSF, KGF, and IL-6, and form a continuous basement membrane compared to deep fibroblasts.…”