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A large number of long non-coding RNAs (lncRNAs) are expressed in animal gonads, but their functions are poorly understood. In this study, a gonad-specific lncRNA, termed lnc4, was identified and characterized in the model fish medaka (Oryzias latipes). The expression pattern and in vitro functional analyses indicated that lnc4 was likely to be a primary transcript of miR-202 (pri-miR-202). Results of single-molecule fluorescence in situ hybridization demonstrated that the precursor miR-202 (pre-miR-202) was highly expressed in the nuclei of testicular somatic cells, including Leydig and Sertoli cells, whereas only a small amount of lnc4 molecules could be detected co-expressed with pre-miR-202 in Sertoli cells due to its low expression level. Deletion of the lnc4 locus led to a significant reduction in testis size and a dramatic decrease in the number of male germ cells, as well as a reduction in sperm viability. Moreover, lnc4 knockout resulted in enhanced synthesis and secretion of testicular somatic cells and accelerated differentiation of immature male germ cells. Taken together, functional studies of lnc4 and its mature transcript miR-202 will contribute to the understanding of the important role of non-coding RNAs in animal or human reproductive disorders., Competing Interests: Declaration of competing interest The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartially of the research reported., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Canine granulomatous colitis (histiocytic ulcerative colitis) is an uncommon disease, predominantly of young French Bulldogs and Boxer dogs, that manifests from a dysregulated immune response, primarily to adherent-invasive Escherichia coli (AIEC). In conjunction with histopathology and periodic acid-Schiff staining, the diagnosis of granulomatous colitis currently relies on fluorescence in situ hybridization (ISH) or immunohistochemistry to identify and localize AIEC organisms within macrophages in the mucosa and/or submucosa. We investigated the utility of ISH for E. coli using formalin-fixed, paraffin-embedded specimens collected from 29 cases of suspected granulomatous colitis. Most confirmed cases of granulomatous colitis were in French Bulldogs (12 of 20; 60%) and Boxers (3 of 20; 15%), and the mean age was 25 ± 6 mo with no sex predilection. E. coli ISH signal localized bacterial genetic material within the mucosa in 20 of 29 (69%) cases, supporting the diagnosis. ISH signal was limited to the lumen in 8 of 29 (28%) cases, which did not support the identification of these organisms as AIEC. The remaining case had no hybridization signal, and the diagnosis of granulomatous colitis was not supported. Our results revealed that ISH is a quick and specific detection method that can effectively confirm the diagnosis of canine granulomatous colitis., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.