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Li WX. Computational simulation of JAK/STAT signaling in somatic versus germline stem cells. Dev Dyn 2024; 253:648-658. [PMID: 38126664 PMCID: PMC11190031 DOI: 10.1002/dvdy.684] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Revised: 11/20/2023] [Accepted: 12/10/2023] [Indexed: 12/23/2023] Open
Abstract
BACKGROUND The Janus kinase/signal transducer and activator of transcription (JAK/STAT) signaling pathway regulates a variety of cellular processes. A major activation event in this pathway involves the phosphorylation of a tyrosine of STAT, converting unphosphorylated STAT (uSTAT) to phosphorylated STAT (pSTAT), an active transcription factor. In a noncanonical role, uSTAT contributes to the maintenance of heterochromatin stability. As such, an increase in pSTAT concurrently reduces uSTAT, resulting in heterochromatin loss, as observed in Drosophila somatic tissues. Paradoxically, an opposing phenomenon occurs in Drosophila male germline stem cells (GSCs), where the JAK/STAT pathway remains persistently active due to a continuous supply of ligands. Here, computational simulations were employed to dissect JAK/STAT pathway activation under different cellular contexts, mimicking somatic and germline cells. In these simulations, ordinary differential equations were leveraged to replicate the chemical reactions governing JAK/STAT signaling under different conditions. RESULTS The outcomes indicate that transient ligand stimulation, typical in somatic tissues, led to a momentary reduction in uSTAT levels. Conversely, sustained ligand stimulation, a characteristic feature of the GSC niche, resulted in elevated uSTAT levels at equilibrium. CONCLUSION The simulation suggests that the duration of ligand exposure could explain the observed opposite effects of JAK/STAT activation on heterochromatin in somatic versus GSCs.
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Affiliation(s)
- Willis X Li
- Department of Medicine, University of California San Diego, La Jolla, California, USA
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Cui H, Huang Q, Li J, Zhou P, Wang Z, Cai J, Feng C, Deng X, Gu H, He X, Tang J, Wang X, Zhao X, Yu J, Chen X. Single-cell RNA sequencing analysis to evaluate antimony exposure effects on cell-lineage communications within the Drosophila testicular niche. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 270:115948. [PMID: 38184976 DOI: 10.1016/j.ecoenv.2024.115948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 01/09/2024]
Abstract
The increasing production and prevalence of antimony (Sb)-related products raise concerns regarding its potential hazards to reproductive health. Upon environmental exposure, Sb reportedly induces testicular toxicity during spermatogenesis; moreover, it is known to affect various testicular cell populations, particularly germline stem cell populations. However, the cell-cell communication resulting from Sb exposure within the testicular niche remains poorly understood. To address this gap, herein we analyzed testicular single-cell RNA sequencing data from Sb-exposed Drosophila. Our findings revealed that the epidermal growth factor receptor (EGFR) and WNT signaling pathways were associated with the stem cell niche in Drosophila testes, which may disrupt the homeostasis of the testicular niche in Drosophila. Furthermore, we identified several ligand-receptor pairs, facilitating the elucidation of intercellular crosstalk involved in Sb-mediated reproductive toxicology. We employed scRNA-seq analysis and conducted functional verification to investigate the expression patterns of core downstream factors associated with EGFR and WNT signatures in the testes under the influence of Sb exposure. Altogether, our results shed light on the potential mechanisms of Sb exposure-mediated testicular cell-lineage communications.
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Affiliation(s)
- Hongliang Cui
- Department of Urology, Nantong Hospital of Traditional Chinese Medicine, Nantong 226001, China
| | - Qiuru Huang
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Jiaxin Li
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Peiyao Zhou
- Department of Occupational Medicine and Environmental Toxicology, Nantong Key Laboratory of Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China
| | - Zihan Wang
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Jiaying Cai
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Chenrui Feng
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Xiaonan Deng
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Han Gu
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Xuxin He
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China
| | - Juan Tang
- Department of Occupational Medicine and Environmental Toxicology, Nantong Key Laboratory of Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China
| | - Xiaoke Wang
- Department of Occupational Medicine and Environmental Toxicology, Nantong Key Laboratory of Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China
| | - Xinyuan Zhao
- Department of Occupational Medicine and Environmental Toxicology, Nantong Key Laboratory of Environmental Toxicology, School of Public Health, Nantong University, Nantong 226019, China.
| | - Jun Yu
- Institute of Reproductive Medicine, School of Medicine, Nantong University, Nantong 226001, China.
| | - Xia Chen
- Department of Obstetrics and Gynecology, Nantong First People's Hospital, Affiliated Hospital 2 of Nantong University, Nantong University, Nantong 226001, China.
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Xing Y, Larson K, Li J, Li WX. Canonical and non-canonical functions of STAT in germline stem cell maintenance. Dev Dyn 2023; 252:728-741. [PMID: 36866634 PMCID: PMC10238624 DOI: 10.1002/dvdy.576] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 02/24/2023] Open
Abstract
BACKGROUND Maintenance of the Drosophila male germline stem cells (GSCs) requires activation of the Janus kinase/signal transducer and activators of transcription (JAK/STAT) pathway by niche signals. The precise role of JAK/STAT signaling in GSC maintenance, however, remains incompletely understood. RESULTS Here, we show that, GSC maintenance requires both canonical and non-canonical JAK/STAT signaling, in which unphosphorylated STAT (uSTAT) maintains heterochromatin stability by binding to heterochromatin protein 1 (HP1). We found that GSC-specific overexpressing STAT, or even the transcriptionally inactive mutant STAT, increases GSC number and partially rescues the GSC-loss mutant phenotype due to reduced JAK activity. Furthermore, we found that both HP1 and STAT are transcriptional targets of the canonical JAK/STAT pathway in GSCs, and that GSCs exhibit higher heterochromatin content. CONCLUSIONS These results suggest that persistent JAK/STAT activation by niche signals leads to the accumulation of HP1 and uSTAT in GSCs, which promote heterochromatin formation important for maintaining GSC identity. Thus, the maintenance of Drosophila GSCs requires both canonical and non-canonical STAT functions within GSCs for heterochromatin regulation.
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Affiliation(s)
- Yalan Xing
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
| | - Kimberly Larson
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
| | - Jinghong Li
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
| | - Willis X. Li
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093
- Department of Biomedical Genetics, University of Rochester Medical Center, Rochester, NY 14642
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