Biology subjects

Kremer, J. L.

Publications and source records attributed to Kremer, J. L..

2 recordsLinked to original sources

bioRxiv2025

Deciphering the intra-tissue specific Collagen PTMs site-specific heterogeneity in Human Adrenal extracellular-matrix

The human adrenal is one of the pivotal glands of the endocrine system. Recently, the extracellular matrix (ECM) of the adrenal capsule and cortex was explored by dividing them into two fractions: outer (OF) and inner (IF). A significant variation in the levels of ECM proteins, including collagens, was documented. During the biosynthesis of collagen, it undergoes a plethora of PTMs exhibiting crucial roles such as cell-matrix interaction, adhesion, crosslinking, stability, etc. However, the site-specific identification and characterization of collagen PTMs remained challenging and is unknown for the human adrenal gland. We applied our in-house developed proteomics pipeline to identify several PTMS in 25 collagen chains from human adrenal-ECM. In the entire collagenome, we identified a total of 963 4-hydroxyproline (4-HyP), 201 3-hydroxyproline (3-HyP), 105 hydroxylysine (HyK), 17 galactosyl-hydroxylysine (G-HyK), and 35 glucosyl galactosyl-hydroxylysine (GG-HyK) sites. Although the site-specificity of collagen PTMs (3-HyP, HyK, G/GG-HyK) across fractions is conserved, the occupancies were different in a site-specific manner. Classically, a fully 3-hydroxylated site (P1164) of COL1A1 associated with osteogenesis imperfecta was found to be approximately fully hydroxylated ([~]99%) across fractions. Similarly, we also looked at the microheterogeneity of lysine modifications on one lysine residue (K862) of COL1A1. We observed that the hydroxylation level was higher in OF, while glycosylation levels were higher in IF. This may suggest a change in the crosslinking of collagen I across both fractions. Further, our analysis revealed much higher site-specific O-glycosylation in basement membrane collagen-IV, potentially facilitating the secretion of steroids from the adrenal gland. For the first time, we have annotated the collagen PTMs, developed a COL1A1 PTM map, and quantitated site-specific PTMs in the human adrenal gland. Taken together, this work revealed that intra-tissue-specific site-specific PTM collagen heterogeneity and lay the foundation for understanding their role in region-specific functions.

biochemistry↗

bioRxiv2025

Glutamine antagonism suppresses tumor growth in adrenocortical carcinoma through inhibition of de novo nucleotide biosynthesis

Dysregulation of cellular metabolism is a hallmark of cancer, which remains poorly understood in adrenocortical carcinoma (ACC). Here, we dissected ACC metabolism by integrating transcriptional profiling from human and mouse ACC, targeted tissue metabolomics from a mouse ACC model, and untargeted serum metabolomics from a large patient cohort, providing cross-species validation of metabolic rewiring in ACC. This study revealed global metabolic dysregulation, involving glutamine-dependent pathways such as non-essential amino-acid and hexosamine biosynthesis, nucleotide metabolism, and glutathione biosynthesis, suggesting glutamine catabolism is a critical metabolic vulnerability in ACC. Treatment with glutamine antagonists 6-Diazo-5-Oxo-L-Norleucine (DON) and JHU-083 elicited robust anti-tumor responses. Mechanistic studies revealed DONs anti-tumor effect was primarily driven by selective inhibition of glutamine-fueled de novo nucleotide biosynthesis. Additionally, DON led to DNA damage, which yielded potent synergism with inhibition of the DNA damage response pathway. Collectively, this work highlights glutamine metabolism as a central metabolic dependency and therapeutic target in ACC. HighlightsO_LIMouse and human ACC share conserved transcriptional-metabolic programs, revealing Gln metabolism as a central, targetable vulnerability. C_LIO_LITargeted tissue metabolomic analysis in a mouse model of ACC validates dysregulation in Gln-dependent metabolic pathways. C_LIO_LITargeting of Gln metabolism with JHU-083 (6-diazo-5-oxo-L-norleucine (DON) pro-drug) achieves marked inhibition of tumor growth in vivo. C_LIO_LIHigh expression of Gln-metabolizing genes mediating de novo nucleotide biosynthesis is associated with poor prognosis in ACC. C_LIO_LIDON drives nucleotide depletion and DNA damage, leading to potent synergy with inhibition of the DNA damage response. C_LIO_LIUntargeted serum metabolomic analysis in a large cohort of patients with adrenal tumors demonstrates dysregulation of Gln and nucleotide metabolism in ACC. C_LI

cancer biology↗