Fibronectins are adhesive glycoproteins that can be found in tissue matrices and circulating in various fluids of the body. The variable composition of fibronectin molecules facilitates a diversity of interactions with cell surface receptors that suggest a role for these proteins beyond the structural considerations of the extracellular matrix. These interactions implicate fibronectin in the regulation of mechanisms that also determine cell behavior and activity. The two major forms, plasma fibronectin (pFn) and cellular fibronectin (cFn), exist as balanced amounts under normal physiological conditions. However, during injury and/or disease, tissue and circulating levels of cFn become disproportionately elevated. The accumulating cFn, in addition to being a consequence of prolonged tissue damage, may in fact stimulate cellular events that promote further damage. In this review, we summarize what is known regarding such interactions between fibronectin and cells that may influence the biological response to injury. We elaborate on the effects of cFn in the liver, specifically under a condition of chronic alcohol-induced injury. Studies have revealed that chronic alcohol consumption stimulates excess production of cFn by sinusoidal endothelial cells and hepatic stellate cells while impairing its clearance by other cell types resulting in the build up of this glycoprotein throughout the liver and its consequent increased availability to influence cellular activity that could promote the development of alcoholic liver disease. We describe recent findings by our laboratory that support a plausible role for cFn in the promotion of liver injury under a condition of chronic alcohol abuse and the implications of cFn stimulation on the pathogenesis of alcoholic liver disease. These findings suggest an effect of cFn in regulating cell behavior in the alcohol-injured liver that is worth further characterizing not only to gain a more comprehensive understanding of the role this reactive glycoprotein plays in the progression of injury but also for the insight further studies could provide towards the development of novel therapies for alcoholic liver disease.

Altogether, these results show that cFn stimulates KCs to produce factors that may enhance the promotion of tissue damage and that ethanol administration increases these responses.

B cell development past the pro-B cell stage in mice requires the Cul4-DDB1-Roc1 E3 ubiquitin ligase substrate recognition subunit VprBP. Enforced Bcl2 expression overcomes defects in distal VH-DJH and secondary Vκ-Jκ rearrangement associated with VprBP-insufficiency in B cells, and substantially rescues maturation of marginal zone and Igλ+ B cells, but not Igκ+ B cells. In this background, expression of a site-directed Igκ light chain transgene increases Igκ+ B cell frequency, suggesting VprBP does not regulate light chain expression from a productively rearranged Igk allele. In site-directed anti-dsDNA heavy chain transgenic mice, loss of VprBP function in B cells impairs selection of Igκ “editor” light chains typically arising through secondary Igk rearrangement, but not selection of Igλ editor light chains. Both heavy and light chain site-directed transgenic mice show increased B cell anergy when VprBP is inactivated in B cells. Taken together, these data argue that VprBP is required for the efficient receptor editing and selection of Igκ+ B cells, but is largely dispensable for Igλ+ B cell development and selection, and that VprBP is necessary to rescue autoreactive B cells from anergy induction.

Undifferentiated intramucosal EGC smaller than 2.5 cm without lymphatic involvement was not associated with lymph node metastasis. Thus, we propose in this circumstance that endoscopic mucosal resection could be considered a definitive treatment without compromising the possibility of cure.

These results suggest that the elevated amounts of cFn observed in alcoholic liver injury can stimulate hepatocytes to produce factors which promote further tissue damage.