With the increased awareness about the importance of the composition, organization, and stiffness of the extracellular matrix (ECM) for tissue homeostasis, there is a renewed need to understand the details of how cells recognize, assemble and remodel the ECM during dynamic tissue reorganization events. Fibronectin (FN) and fibrillar collagens are major proteins in the ECM of interstitial matrices. Whereas FN is abundant in cell culture studies, it is often only transiently expressed in the acute phase of wound healing and tissue regeneration, by contrast fibrillar collagens form a persistent robust scaffold in healing and regenerating tissues. Historically fibrillar collagens in interstitial matrices were seen merely as structural building blocks. Cell anchorage to the collagen matrix was thought to be indirect and occurring via proteins like FN and cell surface-mediated collagen fibrillogenesis was believed to require a FN matrix. The isolation of four collagen-binding integrins have challenged this dogma, and we now know that cells anchor directly to monomeric forms of fibrillar collagens via the α1β1, α2β1, α10β1 and α11β1 integrins. The binding of these integrins to the mature fibrous collagen matrices is more controversial and depends on availability of integrin-binding sites. With increased awareness about the importance of characterizing the total integrin repertoire on cells, including the integrin collagen receptors, the idea of an absolute dependence on FN for cell-mediated collagen fibrillogenesis needs to be re-evaluated. We will summarize data suggesting that collagen-binding integrins in vitro and in vivo are perfectly well suited for nucleating and supporting collagen fibrillogenesis, independent of FN.

Background Arsenic is one of the major toxic elements in the environment and is also known to be carcinogenic, with several other health side effects in human beings. Due to the lack of a sufficient supply of treated piped water across Uganda, boreholes are increasingly becoming an important water source for both domestic and commercial purposes. We determined the concentrations of arsenic in water obtained from underground wells and biological samples from residents in the Amuria district of Uganda. Methods We conducted a field-based, cross-sectional observational study to determine arsenic levels in underground water sources in Amuria District. Water samples were collected from boreholes and underground wells, alongside biological samples, including hair and nails, obtained from residents. Arsenic concentrations were quantified using an Agilent Atomic Absorption Spectrometer. Results The arsenic levels in the borehole-water from the different villages were all extremely above the WHO maximum acceptable concentration of 10 μg/L. The arsenic concentration in the sampled borehole water ranged from 4040 ± 973.6 μg/L to 5767.14 ± 258.3 μg/L. The arsenic concentrations in the hair and nail samples collected ranged from 0.02 ± 0.008 μg/g to 0.0045 ± 0.002 μg/g and from 0034 ± 0.001 μg/g to 0.00084 ± 0.0004 μg/g, respectively. Conclusion The borehole-water samples collected from villages of Amuria district had a significantly higher arsenic concentration than the recommended (10 μg/L) by WHO. The arsenic was also present in the biological samples of the residents who rely on the borehole-water for domestic purposes, but no significant correlation was established between water and nail or hair arsenic levels.