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The thymus, a vital immune organ in humans, plays a crucial role in the differentiation and development of T cells. Its normal development commences around the fourth week of gestation, originating from the ectoderm of the third branchial cleft and the endoderm of the third parotid pouch. By the 7-8th week of gestation, the primary thymus migrates towards the central axis. However, various factors may disrupt this process, leading to congenital anomalies such as incomplete descent of thymus tissue. Persistence of residual thymus tissue can result in the formation of ectopic thymus. Although ectopic thymus is rare in clinical practice, sporadic cases have been reported in the neck or mediastinum, with fewer occurrences in the pericardium, chest wall, axilla, and thyroid gland. It is estimated that ectopic thymus accounts for approximately 0.4% of neck masses, and improper removal may predispose the child to immune deficiencies. This article focuses on a neonatal patient presenting with respiratory failure, where a foreign body was discovered in the oral cavity during weaning from mechanical ventilation. Subsequently, the tumor progressively enlarged postextubation. Surgical excision of the tumor revealed pathological abnormalities upon hematoxylin-eosin (HE) staining, confirming ectopic thymus tissue. B-ultrasound examination confirmed the presence of thymus tissue, and the child's condition improved, leading to hospital discharge. Follow-up assessments showed no evidence of immune deficiency in the child.

Abstract Diabetes, a metabolic disorder characterized by hyperglycemia, underscores the importance of normal pancreatic β‐cell development and function in maintaining glucose homeostasis. Poly(A)‐specific ribonuclease (PARN) serves as the principal regulator of messenger RNA (mRNA) stability, yet its specific role in pancreatic β cells remains unclear. This study utilizes mice with targeted PARN deficiency in β cells to elucidate this role. Notably, Parn conditional knockout mice present unaltered β‐cell development and insulin sensitivity but reduced glucose‐stimulated insulin secretion (GSIS). The observed outcomes are corroborated in NIT‐1 cells. Furthermore, transcriptomic analyses reveal aberrant mRNA expression of genes crucial for insulin secretion in PARN‐deficient β cells. Insights from linear amplification of complementary DNA ends and sequencing and coimmunoprecipitation experiments reveal an interaction between PARN and polypyrimidine tract‐binding protein 1 (PTBP1), regulating the RNA stability of solute carrier family 30, member 8 (Slc30a8) and carbohydrate sulfotransferase 3 (Chst3). Interference with either PARN or PTBP1 disrupts this stability. These data indicate that PARN deficiency hampers GSIS and insulin maturation by destabilizing Slc30a8 and Chst3 RNAs. These findings provide compelling evidence indicating that PARN is a potential therapeutic target for enhancing insulin maturation and secretion.

Spermatogonial stem cells (SSCs) are essential for continuous spermatogenesis and male fertility. The underlying mechanisms of alternative splicing (AS) in mouse SSCs are still largely unclear. We demonstrated that SRSF1 is essential for gene expression and splicing in mouse SSCs. Crosslinking immunoprecipitation and sequencing data revealed that spermatogonia-related genes (e.g. Plzf, Id4, Setdb1, Stra8, Tial1/Tiar, Bcas2, Ddx5, Srsf10, Uhrf1, and Bud31) were bound by SRSF1 in the mouse testes. Specific deletion of Srsf1 in mouse germ cells impairs homing of precursor SSCs leading to male infertility. Whole-mount staining data showed the absence of germ cells in the testes of adult conditional knockout (cKO) mice, which indicates Sertoli cell-only syndrome in cKO mice. The expression of spermatogonia-related genes (e.g. Gfra1, Pou5f1, Plzf, Dnd1, Stra8, and Taf4b) was significantly reduced in the testes of cKO mice. Moreover, multiomics analysis suggests that SRSF1 may affect survival of spermatogonia by directly binding and regulating Tial1/Tiar expression through AS. In addition, immunoprecipitation mass spectrometry and co-immunoprecipitation data showed that SRSF1 interacts with RNA splicing-related proteins (e.g. SART1, RBM15, and SRSF10). Collectively, our data reveal the critical role of SRSF1 in spermatogonia survival, which may provide a framework to elucidate the molecular mechanisms of the posttranscriptional network underlying homing of precursor SSCs.