ALCOHOL AND IMPAIRED LIVER REGENERATION: EFFECTS ON MITOGENIC SIGNALING PATHWAYS

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Patients who regularly consume alcohol are slow to recover from liver injury because alcohol poisons the liver's capacity to regenerate itself (grow back). Hence patients with alcohol-induced liver disease have a high mortality and prolonged hospital stays. The applicants have been supported by NHMRC to study how alcohol impairs liver regeneration. They found that the effect is at the level of cell surface receptors for the growth factors that control liver regeneration. Alcohol alters the function of these receptors. One major discovery has been that it damages the capacity to generate a rise in calcium within the cell, something that is fundamentally required for any cell to divide and reproduce itself. Thus when a rise in calcium was produced artificially (with chemicals to unlock the internal calcium stores), liver cells from alcohol-fed rats once more responded normally under the influence of growth factors and replicated themselves. The present work isdesigned to find out where this effect of calcium is exerted. The investigators believe that it is related to how other types of signals work, the so-called protein kinase pathways. These are cascades of one protein turning on (activating) the next down the line to ultimately switch on the genes that control cell growth. They will manipulate liver cells from alcohol-fed rats in culture to establish which of these pathways is most affected, and which is the most critical for the control of cell division genes. These studies will greatly advance our understanding about how alcohol impairs liver regeneration. They will give new insight into the control of liver cell growth and division that is such a crucial response of the liver to injury, vital for survival of the liver. This kind of knowledge will open the door for new treatments to be designed that can control liver growth - turn it back on when it has been poisoned, or turn it off when it is inappropriately vigorous and predisposing to liver cancer.