# Project 1: Functional Analysis of Age-Specific FSH Analogs Using Genetically Altered Mice

> **NIH NIH P01** · WICHITA STATE UNIVERSITY · 2024 · $381,244

## Abstract

PROJECT SUMMARY/ABSTRACT – Project 1(Kumar)
The long-term goal of Project 1 is to study the mechanisms of follicle-stimulating hormone (FSH) actions in
gonads and extra-gonadal tissues in the aging female. Both the FSH subunits are glycosylated with two N-linked
sugar chains on each subunit. It is known that glycosylation of FSH is estrous/menstrual cycle- and age-specific.
Previous studies identified FSH variants consisting of 2 sugar chains on the α but either one or none on the β
subunit. These variants are known as hypoglycosylated FSH glycoforms and designated as FSH21, and FSH18,
in contrast to the fully glycosylated FSH24. Most importantly, the ratio of hypo- (FSH21 or FSH18) to fully-
glycosylated FSH forms (FSH24) is age-dependent, with high levels of FSH21/18 glycoforms predominant in
young age for optimal ovarian function and high levels of FSH24 predominantly present in peri/post-menopausal
women and may contribute to the aging-associated bone loss. However, the distinct in vivo biological functions
of these changing ratios of FSH glycoforms in vivo are unknown in ovarian and bone physiology in aging.
Moreover, whether the documented FSH actions on bone are mediated via the bona-fide ovarian FSH receptors
has never been tested. The central hypothesis is that estrogen regulates an age-dependent glycosylation switch
on FSH and the resulting shift in higher abundance of fully-glycosylated FSH24 mediates bone-specific actions
via FSH receptors on osteoclasts. This hypothesis will be tested using genetically engineered novel mouse
models. In Aim 1, we will purify GFP-tagged gonadotropes from young and old age female mouse pituitaries by
flow sorting and perform RNA-Seq analysis to identify age-specific and estrogen-dependent glycosylation
pathway enzymes. Additionally, we will introduce an HFSHB24 transgene onto gonadotrope-specific Esr1
conditional null background and determine whether loss of estrogen signaling leads to changes in abundance of
FSH glycoforms. In Aim 2, we will engineer Fshb null mice expressing either a FSH18 or a FSH21 hypo-
glycosylated form and a Tet-inducible HFSHB24 transgene. This genetic strategy will allow us to temporally
regulate at desired times, the age-specific changing ratios of FSH glycoforms and test systematically the in vivo
biological actions of changing ratios of FSH glycoforms in ovarian physiology in the absence of endogenous
mouse FSH. In Aim 3, we will selectively delete Fshr in osteoclasts by a Cre-lox genetic approach to
unequivocally test the direct cell-autonomous actions of FSH in osteoclasts in the bone. Successful completion
of Project 1 studies may unravel a novel phenomenon of age-dependent N-glycosylation switch on FSH resulting
in alterations in target tissue specificity (ovary versus bone) and may potentially lead to new therapeutic options
for preserving ovarian function and intervention of bone loss in aging women. The three Aims of Project 1 are
well integrated into the overall P01 ...

## Key facts

- **NIH application ID:** 10848232
- **Project number:** 5P01AG029531-12
- **Recipient organization:** WICHITA STATE UNIVERSITY
- **Principal Investigator:** T. RAJENDRA KUMAR
- **Activity code:** P01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $381,244
- **Award type:** 5
- **Project period:** 2009-04-15 → 2028-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10848232

## Citation

> US National Institutes of Health, RePORTER application 10848232, Project 1: Functional Analysis of Age-Specific FSH Analogs Using Genetically Altered Mice (5P01AG029531-12). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10848232. Licensed CC0.

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