{"doi":"10.1101/2023.09.08.556759","title":"Dual Role of Neuroplastin in Pancreatic β Cells: Regulating Insulin Secretion and Promoting Islet Inflammation","abstract":"Abstract Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-resident secretory protein that reduces inflammation and promotes proliferation in pancreatic β cells. Numerous studies have highlighted the potential of MANF as a therapeutic agent for diabetes mellitus (DM), making it essential to understand the mechanisms underlying MANF’s functions. In our previous search for a molecule that mediates MANF signaling, we identified Neuroplastin (NPTN) as a binding partner of MANF that localizes on the cell surface. However, the roles of NPTN in pancreatic β cells remain unclear. In this study, we generated β cell-specific Nptn knockout (KO) mice and conducted metabolic characterization. NPTN deficiency improved glucose tolerance by increasing insulin secretion and β cell mass in the pancreas. Moreover, proliferation and mitochondrial numbers in β cells increased in Nptn KO islets. These phenotypes resulted from elevated cytosolic Ca 2+ levels and subsequent activation of downstream molecules. Simultaneously, we demonstrated that NPTN induces the expression of proinflammatory cytokines via the TRAF6-NF-κB axis in β cells. Additionally, NPTN deficiency conferred resistance to STZ-induced diabetic phenotypes. Finally, exogenous MANF treatment in islets or β cells led to similar phenotypes as those observed in NPTN-deficient models. These results indicate that NPTN plays important roles in the regulation of insulin secretion, proliferation, and mitochondrial quantity, as well as pro-inflammatory responses, which are antagonized by MANF treatment. Thus, targeting the MANF-NPTN interaction may lead to a novel treatment for improving β cell functions in diabetes mellitus. Significance statement Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER)-resident small secretory protein that has the potential as therapeutic agent for various diseases related to inflammation and ER stress, such as Type 1 diabetes mellitus. Our work shed light on the roles of a binding partner protein of MANF, Neuroplastin (NPTN), in pancreatic β cells. We demonstrated NPTN regulates Ca 2+ dynamics as well as inflammation in pancreatic β cells. NPTN deficiency caused improved insulin secretion as well as the resistance to Type 1 diabetic phenotypes. We also found out that MANF treatment leads to similar phenotypes observed in NPTN deficient models through antagonizing NPTN’s functions. Overall, our results provide a new insight into treatment for improving β cell functions in diabetes mellitus.","journal":"bioRxiv (Cold Spring Harbor Laboratory)","year":2023,"id":400703,"datarank":0.10397207708399181,"base_score":0.6931471805599453,"endowment":0.6931471805599453,"self_citation_contribution":0.10397207708399181,"citation_network_contribution":0.0,"self_endowment_contribution":0.10397207708399181,"citer_contribution":0.0,"corpus_percentile":null,"corpus_rank":null,"citation_count":1,"citer_count":0,"citers_with_citation_signal":0,"citers_with_endowment":0,"datacite_reuse_total":0,"is_dataset":false,"is_dataset_confidence":0.9511,"is_data_producer":false,"deposit_databanks":null,"is_oa":true,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2023-01-01","fair_score":null,"fair_percentile":null,"algorithm_id":"datarank_citation_only_1hop_v6","ranking_scope":"data_only","authors":[{"id":763112,"name":"Devynn Hummel","orcid":"0000-0003-4919-1429","position":1,"is_corresponding":false},{"id":250010,"name":"Fumihiko Urano","orcid":"0000-0002-9944-6293","position":2,"is_corresponding":false},{"id":831408,"name":"Rie Asada Kitamura","orcid":"0000-0001-8347-6909","position":0,"is_corresponding":true}],"reference_count":84,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-07-19T01:20:04.010538Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"fair_f":null,"fair_a":null,"fair_i":null,"fair_r":null,"fair_zscore":null,"fair_rationale":null,"fair_model":null,"fair_agent_version":null,"fair_fulltext_source":null,"fair_has_llm":null,"fair_computed_at":null,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}