Dr. Guruprasad Kalthur

Identifying and exploring the key deubiquitinase enzyme that facilitates the generation of matured insulin-producing β-cells from human iPSCs- ICMR (2024-2026)

Generating glucose-responsive stem cell–derived β cells in vitro is the need of the day to circumvent the use of human cadaveric islets for cell-based therapy for diabetes. The combination of an unlimited supply of pluripotent stem cell–derived β cells and gene-editing approaches will facilitate numerous in vitro studies not possible with cadaveric islets. However, majority of the approaches available today results in less efficient, immature, polyhormonal and glucose non-responsive β cells. To date no study has emphasized on utilizing the deubiquitinase (DUB) enzyme to obviate the above said limitations and obtain better quality β-cells. The novelty of the proposal lies in identifying and exploring the key DUB that puts the brake on the limitations posed by the present approach of hiPSCs differentiation to β-cells. The key objective of the study is to identify the Key DUB enzyme in the development of pancreas by using hiPSCs reporter system and shRNA library approach. Further study objective is to modulate the identified DUB to the generation of transplantable quality and quantity of β-cells. Finally, the stem cells derived β-cells will be authenticated for their function and maturity both in in vitro and in vivo along with analysing recovery in the ovary function. The outcome of the project accentuates the comprehensive view of key deubiquitinase enzymes in pancreatic development, modulation of which would facilitates the differentiation of human pluripotent stem cells (hPSCs) to pancreatic β-cells and could be utilized for future cell based therapy for β-cell disorders.

Exploring the therapeutic potential of metformin and acarbose co-administration strategy on improving the functional competence of oocyte, embryo development and fetal development in experimentally induced PCOS and type II diabetes- ICMR (2024-2026)

Metformin is the first line drug used in treating PCOS and diabetic mellitus II. Due to its AMH and testosterone reducing effects, it is reported to alter the intrauterine microenvironment during the gestation period. Moreover, since in PCOS and diabetic condition, metformin is administered throughout the pregnancy, it is expected to have detrimental effects on foetal gonadal development. Even though few clinical studies report altered postnatal developmental characteristics in the progenies born to metformin exposed women, there are no reports in the literature to demonstrate the effect of metformin on the functional competence of gametes. To overcome the concerns of using metformin, few efforts are made in the past by using co-administration strategy using compounds like acarbose to reduce the dose of metformin. However, there are not enough experimental evidence to support the benefit of using acarbose along with metformin in PCOS and diabetic conditions. To address these issues, the present study is proposed to understand the effects of metformin on the foetal gonadal development, expression of genes regulating gonadal development and, epigenetic changes in gametes of progenies under PCOS and diabetic conditions. Further, the study will throw light on the advantages of following acarbose and metformin co-administration strategy.

Long-term Effects of Repeated Ovulation Induction-induced Changes in Hormone Sensitive Organs- an Experimental Study - DBT (2023-2026)

Ovulation induction in infertile woman is a common practice in assisted reproductive technology (ART). Due to low success rate of ART, most of the time the female partner of infertile couple undergoes controlled ovarian hyperstimulation (COH) repeatedly. Similarly, professional oocyte donors are also exposed to repeated COH. The key questions or issues to be addressed with respect to the consequences of these treatments on the health of the female are i) whether repeated COH protocol alters the function and structural organization of hormone sensitive organs like ovary, endometrium and mammary gland; and ii) whether these changes induced are transient and reversible; iii) whether COH protocol increases the cancer risk in hormone sensitive organs.

Understanding the clomiphene citrate-induced changes in secretory epithelial cells of human fallopian tube - ICMR (2021-2024)

Clomiphene citrate (CC) is considered as first line drug for infertility treatments involving mild ovulation induction. However, higher incidence of ectopic pregnancy, miscarriage rate and elevated risk of fetal malformations over other drugs warrants in-depth research on understanding the complex action of CC on female reproductive function. Fallopian tube is an important organ, which not only plays a critical role in oocyte transport, sperm storage and embryo transport but also creates a conducive environment for fertilization and preimplantation embryo development. It is interesting to know whether the low pregnancy rate and abnormal pregnancy outcomes induced by CC is due to perturbations in fallopian tube microenvironment. In the proposed study we intend to understand the effect of CC on the function of secretory cells, which regulates the sperm-oocyte interaction to facilitate fertilization, early embryo development and embryo transport using human fallopian tube secretory cells and the mouse model.

Link-

https://www.scopus.com/authid/detail.uri?authorId=57208450546

https://scholar.google.com/citations?hl=en&user=zgxAhiIAAAAJ

Key publications- 1. Dcunha R, Kumari S, Najar MA, Aravind A, Suvarna KS, Hanumappa A, Mutalik SP, Mutalik S, Kalthur SG, Rajanikant GK, Siddiqui S, Alrumman S, Alamri SAM, Raghu SV, Adiga SK, Kannan N, Thottethodi SKP, Kalthur G. High doses of clethodim-based herbicide GrassOut Max poses reproductive hazard by affecting male reproductive function and early embryogenesis in Swiss albino mice. Chemosphere. 2023;336:139215.

2. Poojary PS, Nayak G, Panchanan G, Rao A, Kundapur SD, Kalthur SG, Mutalik S, Adiga SK, Zhao Y, Bakkum-Gamez J, Chang AY, DeStephano C, Sherman M, Kannan N, Kalthur G. Distinctions in PCOS Induced by Letrozole Vs Dehydroepiandrosterone With High-fat Diet in Mouse Model. Endocrinology. 2022;163(9):bqac097. 

3. Poojary KK, Nayak G, Vasani A, Kumari S, Dcunha R, Kunhiraman JP, Gopalan D, Rao RR, Mutalik S, Kalthur SG, Murari MS, Raghu SV, Adiga SK, Kalthur G. Curcumin nanocrystals attenuate cyclophosphamide-induced testicular toxicity in mice. Toxicol Appl Pharmacol. 2021;433:115772.  

4. Satish M, Kumari S, Deeksha W, Abhishek S, Nitin K, Adiga SK, Hegde P, Dasappa JP, Kalthur G, Rajakumara E. Structure-based redesigning of pentoxifylline analogs against selective phosphodiesterases to modulate sperm functional competence for assisted reproductive technologies. Sci Rep. 2021;11(1):12293.  

5. Hegde S, Poojary KK, Rasquinha R, Crasta DN, Gopalan D, Mutalik S, Siddiqui S, Adiga SK, Kalthur G. Epigallocatechin-3-gallate (EGCG) protects the oocytes from methyl parathion-induced cytoplasmic deformities by suppressing oxidative and endoplasmic reticulum stress. Pestic Biochem Physiol. 2020;167:104588.