Distribution of α(IV) collagen chains in the ocular anterior segments of adult mice

Abstract

The distribution of the collagen chains from α1(IV) to α6(IV) could serve as a basis for the characterization of type IV collagen. In this study, immunohistochemistry of the ocular anterior segment of adult mice was performed using specific monoclonal antibodies against each chain in the series from α1(IV) to α6(IV). The results show that the components of type IV collagen in vascular basement membranes are α1(IV) and α2(IV) with or without α5(IV) and α6(IV) chains and those in epithelium and muscle basement membranes are α1(IV), α2(IV), α5(IV), and α6(IV) chains. In corneal endothelium, pigmented epithelium of iris and ciliary body, and trabecular meshwork, α3(IV) and α4(IV) chains are also expressed in addition to α1(IV), α2(IV), α5(IV), and α6(IV) chains. Moreover, we investigated the change in molecular composition in ciliary body during postnatal development. α3(IV) and α4(IV) chains were also expressed in addition to α1(IV), α2(IV), α5(IV), and α6(IV) chains in ciliary pigmented epithelium basement membrane from 7 days after birth. This result suggests that the basement membranes gradually change their biochemical features owing to temporal regulation. Taken together, these findings suggest that the different distribution and the developmental expression of α1(IV) to α6(IV) chains are associated with the tissue-specific function of type IV collagen in basement membranes.

Whole exome analysis identifies dominant COL4A1 mutations in patients with complex ocular phenotypes involving microphthalmia

“…Careful evaluation of all published COL4A1 mutation reports that presented ophthalmological findings revealed that microphthalmia was reported in 4 of 97 cases with cerebrovascular disease (20,(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38); while no images or details were provided in these manuscripts, this supports our finding of COL4A1 mutations in A/M. COL4A1 is ubiquitously expressed in basement membranes, including in the cornea, lens and retina, and is important for their stability (39). COL4A1 contains three domains: the N-terminal 7S domain, a triple-helix (collagenous) domain and a C-terminal non-collagenous (NC1) domain.…”

Inhibition of microRNA-214-5p promotes cell survival and extracellular matrix formation by targeting collagen type IV alpha 1 in osteoblastic MC3T3-E1 cells

“…COL4A1 encodes type IV collagen α-chain 1 and is a major component of almost all basement membranes. 37 Recently, it has been reported that the interaction of bone morphogenetic proteins (BMPs) with COL4A1 might partly contribute to bone development, including fracture healing, by its role in vasculogenesis and angiogenesis. 38 Given the aforementioned functions of COL4A1, we speculated that it might be a targeting gene of miR-214-5p and may have played a critical role in fracture healing.…”

Genetics of anterior segment dysgenesis disorders

“…Mouse Col4a1 is expressed in the anterior segment of the eye [76]. Mutations in COL4A1 were initially identified as a cause of porencephaly and brain small vessel disease with stroke and retinal arteriolar tortuosity in some individuals [14, 15] and then also found to be associated with anterior segment ocular anomalies (Table 2) including early-onset cataract [77-79], ARA, corneal opacities, congenital cataract, microcornea, elevated intraocular pressure, and/or glaucoma [80, 81**].…”