Page 115 - CSIR-IGIB Annual Report 2020-21

Inhibiting Diaminopimelate (DAP) pathway of M. Bioinformatics of disease co-morbidities
tuberculosis Type 2 Diabetes Mellitus(T2DM) is on the rise. It is
Our project is aimed at finding a small molecule characterized by hyperglycaemia due to insulin
inhibitor against Mycobacterial resistance and decreased insulin activity. Genetic
Dihydrodipicolinate synthase (Mtb-DHDPS). The factors, environmental agents and their
synthesis of lysine and meso-diaminopimelate (M- interactions have been recognized as contributors
DAP) in mycobacteria are accomplished through to the development of T2DM. The GWAS era
the diaminopimelate (DAP) pathway. Both lysine including meta-analysis enabled uncovering of
and M-DAP are essential for bacterial growth and numerous genes and their variants associated
survival. The crystal structures of Mtb-DapA and with T2DM. Yet these variants apparently are able
its homologues from Escherichia coli, Nicotiana to explain only about 20–30% of heritable
sylvestris, Thermotoga maritima, Clostridium component. Hyperglycaemic conditions in late
botulinum, Corynebacterium glutamicum, Bacillus stages of diabetic individuals include well known
anthracis and Staphylococcus aureus are available. microvascular complications (nephropathy,
The active site residues Thr54, Thr55, Tyr143, neuropathy, retinopathy) and macrovascular
Arg148 and Lys171 of Mtb-DapA are largely complications (atherosclerosis and
conserved among its homologues. Pyruvic acid cardiovascular). Even these complications
forms a Schiff base upon condensation with ε- evidently are polygenic disorders. Other
amino group of the active site Lys161 and ASA complications include Dyslipidemia, Psoriasis etc.
binds to Arg138 located at the entrance of the Gene co-expression analysis has been performed
active site via hydrogen bonding. The search for a using WGCNA package in R to identify similar
potent inhibitor is ongoing. Our work used a expression pattern among different datasets of
comprehensive approach to screen both substrate type 2 diabetes, psoriasis, and atherosclerosis. The
and product analogues of DapA. Small molecule expression of LEP and FABP5 are changing
inhibitors are shortlisted and validated using in noticeably among the datasets. Taken together
silico and in vitro approaches. Shortlisted the expressions of the genes LEP, FABP5, APOE
substrate analogues: β-hydroxypyruvic acid, 2- and ADIPOQ are changing significantly among the
ketobutyric acid, Tartronic acid; Shortlisted atherosclerosis and psoriasis gene expression
product analogues: 6-Hydroxymethyl-pyridine-2- datasets. Therefore, it is our understanding that
carboxylic acid, Pyridine-2-carboxylic acid, 4-Oxo- these genes are informative genes towards further
4-H-pyran 2,6-dicarboxylic acid, 2,6- understanding the progress of the disease from
Pyridinedicarboxylic acid; Shortlisted fluorine the perspective of diabetic dyslipidemia. NF-kB
derivatives of pyruvate and α-KPA: 5,5,5- signaling, TLR signaling, Cytokine interactions,
Trifluoropentanoic acid, Tetrafluoropropanoic Insulin signaling are the highly enriched pathways.
acid and β-Fluoropyruvic acid, 4,4,4-triflurobutyric So, it follows that the principle mechanism of
acid, Trifluoropyruvic acid. In vitro validation using deteriorated metabolic homeostasis is hyper
coupled enzymatic assay shows that these immune activation. In the future we will develop a
compounds are showing considerably good network pathway on the basis of literature
inhibition at 500µM. Fluorescent based thermal curated genes, one each for atherosclerosis and
shift assay shows that the binding of β- psoriasis. We will update the pathway networks
hydroxypyruvic acid to Mtb-DHDPS alters the and modeling of complete integrated pathways
thermal stability (Tm) of the protein. We have to for diabetic dyslipidemia associated co-morbidity.
test a few compounds identified from fragment We are building a software that can be exploited
library screening and use a combination of to make appropriate predictions with respect to
substrate analogue and product analogues. disease progression and treatment.

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