Proteomic profiling of TBC1 domain family member 21-null sperms reveals the critical roles of TEKT 1 in their tail defects.

BACKGROUND: Approximately 7% of the males exhibit reduced fertility; however, the regulatory genes and pathways involved remain largely unknown. TBC1 domain family member 21 (TBC1D21) contains a conserved RabGAP catalytic domain that induces GDP/GTP exchange to inactivate Rabs by interacting with microtubules. We previously reported that Tbc1d21-null mice exhibit severe sperm tail defects with a disrupted axoneme, and that TBC1D21 interacts with RAB10. However, the pathological mechanisms underlying the Tbc1d21 loss-induced sperm tail defects remain unknown. RESULTS: Murine sperm from wild-type and Tbc1d21-null mice were comparatively analyzed using proteomic assays. Over 1600 proteins were identified, of which 15 were significantly up-regulated in Tbc1d21-null sperm. Notably, several tektin (TEKT) family proteins, belonging to a type of intermediate filament critical for stabilizing the microtubular structure of cilia and flagella, were significantly up-regulated in Tbc1d21-/- sperm. We also found that TBC1D21 interacts with TEKT1. In addition, TEKT1 co-localized with RAB10 during sperm tail formation. Finally, we found Tbc1d21-null sperm exhibited abnormal accumulation of TEKT1 in the midpiece region, accompanied by disrupted axonemal structures. CONCLUSIONS: These results reveal that TBC1D21 modulates TEKTs protein localization in the axonemal transport system during sperm tail formation.

[Study on mitigating effect and mechanism of Cichorium glandulosum n-butanol extraction site on CCl_4-induced chronic liver injury in rats].

This study aims to investigate the mitigating effect and mechanism of Cichorium glandulosum n-butanol extraction site(CGE) on the disease in carbon tetrachloride(CCl_4)-induced chronic liver injury model in rats. A chronic liver injury model was constructed by subcutaneous injection of CCl_4 olive oil solution, and after four weeks of CGE treatment, serum levels of aspartate aminotransferase(AST), alanine aminotransferase(ALT), alkaline phosphatase(AKP), hydroxyproline(HYP), interleukin-4(IL-4), interleukin-6(IL-6), malondialdehyde(MDA), superoxide dismutase(SOD), and tumor necrosis factor-α(TNF-α) were detected. Liver tissue was processed by hematoxylin-eosin(HE) staining and Masson staining to observe the structure of the rat liver. qPCR and Western blot were used to examine the expression of transforming growth factor-ß1(TGF-ß1)/small mothers against decapentaplegic(Smad), Toll-like receptor 4(TLR4), α-smooth muscle actin(α-SMA), and fibronectin(Fn) in rat liver tissue and hepatic stellate-T6(HSC-T6) and evaluate the inhibitory effect of CGE on HSC activation. The results showed that CGE could significantly reduce the serum levels of AST, ALT, AKP, HYP, and affect the levels of related inflammatory indexes including IL-4, IL-6, and TNF-α, and MDA in CCl_4-induced chronic liver injury in rats and had no effect on SOD activity, which could delay the process of liver injury, alleviate the hepatic collagen deposition and inflammatory infiltration, and had significant efficacy in mitigating chronic liver injury in rats. CGE could inhibit α-SMA and TLR4 protein expression in the liver tissue and reverse the increased TGF-ß1/Smad, Fn, and TLR4-related expression in HSC-T6 in vitro. The above results indicated that CGE exerted hepatoprotective effects in rats by inhibiting HSC activation and alleviated CCl_4-induced chronic liver injury in rats and could ameliorate inflammatory response and slight liver fibrosis in rat liver tissue. Its pharmacodynamic mechanism might be related to TGF-ß1/Smad and TLR4-related expression.

Unraveling the underlying mechanisms of reduced amyloidogenic properties in human calcitonin via double mutations.

The therapeutic efficacy of peptide-based drugs is commonly hampered by the intrinsic propensity to aggregation. A notable example is human calcitonin (hCT), a peptide hormone comprising 32 amino acids, which is synthesized and secreted by thyroid gland parafollicular cells (C cells). This hormone plays a vital role in regulating blood calcium levels and upholding bone integrity. Despite its physiological importance, utilizing hCT as a drug is hampered by its inclination to form amyloid. To address this limitation, an alternative is provided by salmon calcitonin (sCT), which possesses a lower aggregation propensity. Although sharing the same disulfide bond at the N terminus as hCT, sCT differs from hCT at a total of 16 amino acid positions. However, due to the dissimilarity in sequences, using sCT as a clinical replacement occasionally results in adverse side effects in patients. Earlier investigations have highlighted the significant roles of Tyr-12 and Asn-17 in inducing the formation of amyloid fibrils. By introducing double mutations at these sites, the ability to hinder aggregation can be significantly augmented. This study delves into the oligomerization and helical structure formation of the hCT double mutant (Y12LN17H hCT, noted as DM hCT), as well as two single mutants (Y12L and N17H), aiming to elucidate the mechanism behind hCT fibrillization. In addition, computational prediction tools were employed again to identify potential substitutes. Although the results yielded were not entirely satisfactory, a comparison between the newly examined and previously found hCT double mutants provides insights into the reduced aggregation propensity of the latter. This research endeavor holds the promise of informing the design of more effective therapeutic peptide drugs in the future.

The effects of initial and subsequent overweight or obesity on hypertension in the middle age.

The aims of our study were to examine whether initial or subsequent adiposity status had a greater effect on hypertension. We collected data in 1992 and again in 2007 from the same group of 597 individuals in the middle age. The subjects were classified into four groups: individuals with a normal body mass index (BMI) in 1992 and 2007 were in Group I; those with a normal BMI in 1992, but became overweight or obese in 2007 were in Group II; those who were overweight or obese in 1992, but had a normal BMI in 2007 were in Group III; and those who were overweight or obese in 1992 and 2007 were in Group IV. Their demographic data were recorded. The relationship between adiposity status and hypertension was analyzed using logistic regression model. The cumulative incidence of hypertension was 35.5%, 56.3%, 50.0%, and 65.1% for Group I to IV, respectively. Compared with Group I, after adjusted factors, the hazard ratio (HR) was 1.80 for Group II (P = .001), 1.40 for Group III (P = .150), and 2.31 for Group IV (P < .001). Adiposity status in 2007 could predict hypertension (OR = 2.5, P < .001), as opposed to the initial adiposity status (P = .148). Subsequently adiposity status could have major effects on hypertension. Our society is very short of public health resources, particularly in developing countries, we should pay more attention to current adiposity status and encourage middle-aged people to lose weight.