Ubiquitin D as a potential therapeutic target for NASH, HCC and chronic kidney diseases

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Abstract: Non-alcoholic steatohepatitis (NASH), an advanced form of non-alcoholic fatty liver disease (NAFLD), is one of the major causes of cirrhosis and hepatocellular carcinoma (HCC). There is currently no approved treatment for NASH and patients with advanced fibrosis are at highest risk of mortality due to cardiovascular diseases (CVD). Furthermore, presence of NAFLD increases the risk of chronic kidney disease (CKD) by about 80%. It is not known how NASH and CKD influence each other, but together they can influence CVD and patient mortality. Therefore, a therapeutic target that can improve NASH and its associated co-morbidities such as CKD and CVD will be of great benefit in clinics. We found that Ubiquitin D (UBD) is highly upregulated in NASH livers (primarily in the hepatocytes), HCC tumors and kidneys of CKD mice. Interestingly, UBD was recently found to be one of the six progression-related genes that play a vital role in the progression of NAFLD and positively correlates with steatosis, ballooning, inflammation, fibrosis and NAS score. Similarly, multiple reports link renal UBD to proteinuria and kidney disease. UBD is known to participate in alternative ubiquitination pathway and interact with key cellular proteins such as p53, p62 and MAD2 but the precise mechanism of its role in NASH/HCC and CKD remains unclear. Absence of UBD (in Ubd-/- mice) improved overall metabolic health and extended the mouse lifespan. Despite all the compelling evidences, UBD has not been tested as a therapeutic target for NASH and CKD. Here, we propose to suppress UBD using anti-sense oligos (ASOs) as a therapeutic approach to treat NASH and CKD. We have already developed a “GalNAc” conjugated ASO that is potent in suppressing UBD gene expression in the hepatocytes. Our preliminary data indicates that anti-UBD GalNAc-ASO significantly improved NASH and fibrosis. According to our knowledge, UBD pathway has not been investigated for its therapeutic potential before and also is not a current focus of any industry or academia. Therefore, UBD is a novel target and anti-UBD ASOs provide novel therapeutic leads with a potential to improve both NASH and CKD. We will take advantage of a unique pre-clinical mouse model of diet-induced NASH that also develop CKD and CVD with mortality at later stages (established in our lab). We will address whether anti-UBD ASOs could improve all three disease outcome along with survival benefit. We will supplement this model with additional preclinical models of NASH, HCC and CKD. The following 2 Specific Aims will be addressed in this proposal: Aim 1 will Identify whether UBD suppression prevents NASH and its progression to Cirrhosis and HCC. Additionally, we will translate our findings to human using human primary cell derived 3-D spheroid cell cultures. Aim 2 will investigate the effect of UBD suppression on CKD, CVD and survival benefit either in the context of NASH and/or CKD. Successful completion of the proposed aims will establish UBD as a novel therapeutic target for NASH and CKD.