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The structural integrity of the sperm flagellum is essential for proper sperm function. Flagellar defects can result in male infertility, yet the precise mechanisms underlying this relationship are not fully understood. CCDC181, a coiled-coil domain-containing protein, is known to localize on sperm flagella and at the basal regions of motile cilia. Despite this knowledge, the specific functions of CCDC181 in flagellum biogenesis remain unclear. In this study, Ccdc181 knockout mice were generated. The absence of CCDC181 led to defective sperm head shaping and flagellum formation. Furthermore, the Ccdc181 knockout mice exhibited extremely low sperm counts, grossly aberrant sperm morphologies, markedly diminished sperm motility, and typical multiple morphological abnormalities of the flagella (MMAF). Additionally, an interaction between CCDC181 and the MMAF-related protein LRRC46 was identified, with CCDC181 regulating the localization of LRRC46 within sperm flagella. These findings suggest that CCDC181 plays a crucial role in both manchette formation and sperm flagellum biogenesis.

Infertility represents a significant health concern, with sperm quantity and quality being crucial determinants of male fertility. Oligoasthenoteratozoospermia (OAT) is characterized by reduced sperm motility, lower sperm concentration, and morphological abnormalities in sperm heads and flagella. Although variants in several genes have been implicated in OAT, its genetic etiologies and pathogenetic mechanisms remain inadequately understood. In this study, we identified a homozygous nonsense mutation (c.916C>T, p.Arg306*) in the coiled-coil domain containing 146 ( CCDC146 ) gene in an infertile male patient with OAT. This mutation resulted in the production of a truncated CCDC146 protein (amino acids 1-305), retaining only two out of five coiled-coil domains. To validate the pathogenicity of the CCDC146 mutation, we generated a mouse model ( Ccdc146 mut/mut ) with a similar mutation to that of the patient. Consistently, the Ccdc146 mut/mut mice exhibited infertility, characterized by significantly reduced sperm counts, diminished motility, and multiple defects in sperm heads and flagella. Furthermore, the levels of axonemal proteins, including DNAH17, DNAH1, and SPAG6, were significantly reduced in the sperm of Ccdc146 mut/mut mice. Additionally, both human and mouse CCDC146 interacted with intraflagellar transport protein 20 (IFT20), but this interaction was lost in the mutated versions, leading to the degradation of IFT20. This study identified a novel deleterious homozygous nonsense mutation in CCDC146 that causes male infertility, potentially by disrupting axonemal protein transportation. These findings offer valuable insights for genetic counseling and understanding the mechanisms underlying CCDC146 mutant-associated infertility in human males.

Heat stress affects feed intake, milk production, and endocrine status in dairy cows. The temperature-humidity index (THI) is employed as an index to evaluate the degree of heat stress in dairy cows. However, it is difficult to ascertain whether THI is the most appropriate measurement of heat stress in dairy cows. This experiment was conducted to investigate the effects of heat stress on serum insulin, adipokines (leptin and adiponectin), AMP-activated protein kinase (AMPK), and heat shock signal molecules (heat shock transcription factor (HSF) and heat shock proteins (HSP)) in dairy cows and to research biomarkers to be used for better understanding the meaning of THI as a bioclimatic index. To achieve these objectives, two experiments were performed. The first experiment: eighteen lactating Holstein dairy cows were used. The treatments were: heat stress (HS, THI average=81.7, n=9) and cooling (CL, THI average=53.4, n=9). Samples of HS were obtained on August 16, 2013, and samples of CL were collected on April 7, 2014 in natural conditions. The second experiment: HS treatment cows (n=9) from the first experiment were fed for 8 weeks from August 16, 2013 to October 12, 2013. Samples for moderate heat stress, mild heat stress, and no heat stress were obtained, respectively, according to the physical alterations of the THI. Results showed that heat stress significantly increased the serum adiponectin, AMPK, HSF, HSP27, HSP70, and HSP90 (P<0.05). Adiponectin is strongly associated with AMPK. The increases of adiponectin and AMPK may be one of the mechanisms to maintain homeostasis in heat-stressed dairy cows. When heat stress treatment lasted 8 weeks, a higher expression of HSF and HSP70 was observed under moderate heat stress. Serum HSF and HSP70 are sensitive and accurate in heat stress and they could be potential indicators of animal response to heat stress. We recommend serum HSF and HSP70 as meaningful biomarkers to supplement the THI and evaluate moderate heat stress in dairy cows in the future.