Page 66 - Biennial Report 2018-20 Jun 2021

medical history of each patient along with clinical examinations such as morning stiffness and
joint pain history were recorded. The total phosphoproteins of plasma of OA patients were
quantified by Bradford assay and 2-DE was run. 15 differential spots were identified, analysed
by PDquest software and MALDI-TOF MS/MS analysis. Isoform gamma-A of fibrinogen gamma
chain, apolipoproteins A-I and transthyretin were validated by Western and ELISA.

Further, phospho-proteome profile of synovial fluid (SF) samples of Indian and German OA
patients were studied with an objective to precisely understand the disease pathogenesis on
different geological, community level, diet and lifestyle basis. Here, 26 differentially expressed
protein(DEP) spots were identified by 2DE technique, followed by phosphostaining and silver
staining of gels. Results were analyzed by 2D Delta software and mass spectrometer. The
associated functions of differentially expressed proteins were identified by Ingenuity Pathway
Analysis (IPA) and Gene ontology (GO) annotations whereas STRING 9.0. DAVID, REACTOME
pathway databases, NetPhosK 1.0 server were used to gain the insight into the links among the
identified phosphoproteins. Serum albumin was identified as the most up-regulated protein in
German OA than Indian OA cases that was further studied by in-vitro assays in primary cell
culture, and validated by Western Blot and ELISA. The study thus provided one of the important
significantly potential prognostic biomarker for precise detection of OA pathogenesis along with
other clinical parameters.

CHRONIC SYSTEMIC EXPOSURE TO IL6 CAUSES FATTY LIVER IN ZEBRAFISH

Fatty liver is generally thought to be associated with obesity. Obese patients of non-alcoholic
fatty liver disease (NAFLD) have elevated levels of pro-inflammatory cytokines, especially
Interleukin 6 (IL6). NAFLD in South Asians, especially Indians, is prevalent even in lean individuals
suggesting this might be a different subtype of NAFLD. Intriguingly, Indians also have elevated
levels of IL6 in their serum. Thus, Chetana Sachidanandan’s group hypothesized that in this
subtype of NAFLD chronic systemic exposure to IL6 might be the triggering factor for fatty liver.
They used a constitutive overexpression of human IL6 in zebrafish to create a model to test this
hypothesis. Over-expression of IL6 in the zebrafish heart led to the induction of IL6 signaling in
the liver indicating systemic inflammation in this fish. Examination of the liver in these fish
revealed robust accumulation of fat in the adult male fish.

To further understand the metabolic reprogramming in the liver that caused the fatty liver
phenotype they generated the transcriptomic and proteomic profiles of the normal and fatty
liver. They found a dramatic a down regulation of glycolysis/gluconeogenesis pathways in the
male zebrafish liver with IL6 overexpression. They observed a specially interesting decrease in
the RNA as well as protein levels of the Aldolase B enzyme. This enzyme levels are also down
regulated in the NAFLD and Non-alcoholic steatohepatitis (NASH) patients’ samples, as was
revealed in an analysis of a publicly available NAFLD data set. Aldolase B knock-out mice, a model
for fructose intolerance also show a propensity for fatty liver. They speculated that in the
zebrafish model, the IL6 exposure caused a repression of glycolysis/gluconeogenesis pathway
such that the metabolic intermediates were shunted into triglyceride synthesis. This idea was
further supported by metabolomic profiling of the liver that showed an accumulation of C6-
monophosphates, which are the constitutive intermediates of the glycolytic pathway.

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