6A,B). To exclusively determine that IL30 inhibits IFN-γ expression, the levels of IFN-γ in the blood and in the liver
were measured. Although coadministration of IL12 and IFN-γ induced higher levels of IFN-γ in both serum and the liver, the presence of IL30 resulted in no detectable IFN-γ in either serum or liver (Fig. 6D,E). These results suggest that IL30 is a potent inhibitor of IFN-γ expression and IL12- and IFN-γ-mediated GSK2118436 nmr liver toxicity. The preventive role of IL30 against IL12-induced toxicity described above encouraged us to study whether IL30 also has a therapeutic potential to repair the liver injury once initiated. In this regard, IL30 was administered 2 days after the IL12 treatment and liver toxicity was determined. Two independent methods of gene delivery, electroporation and hydrodynamic delivery, showed that IL30 administration postinjury selleck chemical heals liver injury and reduces the level of toxic IFN-γ expression (Fig. 7A,B). Because chronic inflammation causes liver fibrogenesis, the effect of IL30 was also assessed on hepatic fibrosis during chronic administration of ConA. Treatment with
IL30 by way of gene therapy reduced collagen depositions (Mason’s trichrome staining) (Fig. 8A). Such data reveal that IL30 has therapeutic potential in a clinical setting to reduce liver pathology. To determine how IL30 reduces toxic IFN-γ expression, we determined the transcriptional activity of IL-12-induced IFN-γ in the presence or absence of IL30 over time. Two days after the first treatment, IL30 raised IFN-γ levels, but 5 days after the second treatment IL30 reduced these levels by 10-fold (Supporting Fig.
7). IL30 does not affect the ability of IL12 to produce IFN-γ, nor does it affect cytomegalovirus (CMV)-promoter driven of IL12 ID-8 or IFN-γ expression (Supporting Fig. 8A-C), but instead disrupts constitutive IFN-γ expression once it is initiated, possibly posttranslationally. To better characterize the cellular source of IL30 in the liver, specimens from patients (with or without disease) were stained by way of immunohistochemistry. Interestingly, and never reported before, in normal patients IL30 is highly expressed in the hepatocytes, whereas the levels of expression are lower in the fibrous/connective tissue, further suggesting a protective role of IL30 (Fig. 8B). Although the staining intensity between normal hepatocyte, cirrhosis, and hepatocellular carcinoma (HCC) are similar (Fig. 8B), the data reported previously34 (Supporting Fig. 9) shows that IL30 messenger RNA (mRNA) levels were lower in patients with liver disease (HCC, dysplasia, or cirrhosis) than in healthy livers. The discordance between immunostaining and mRNA detection among patients is associated with the absolute tissue area that expresses IL30.