Trophoblast PR-SET7 dysfunction induces viral mimicry response and necroptosis associated with recurrent miscarriage.

Recurrent miscarriage (RM) is a distressing pregnancy complication. While the etiology of RM remains unclear, growing evidence has indicated the relevance of trophoblast impairment to the pathogenesis of RM. PR-SET7 is the sole enzyme catalyzing monomethylation of H4K20 (H4K20me1) and has been implicated in many pathophysiological processes. However, how PR-SET7 functions in trophoblasts and its relevance to RM remain unknown. Here, we found that trophoblast-specific loss of Pr-set7 in mice led to defective trophoblasts, resulting in early embryonic loss. Mechanistic analysis revealed that PR-SET7 deficiency in trophoblasts derepressed endogenous retroviruses (ERVs), leading to double-stranded RNA stress and subsequent viral mimicry, which drove overwhelming interferon response and necroptosis. Further examination discovered that H4K20me1 and H4K20me3 mediated the inhibition of cell-intrinsic expression of ERVs. Importantly, dysregulation of PR-SET7 expression and the corresponding aberrant epigenetic modifications were observed in the placentas of RM. Collectively, our results demonstrate that PR-SET7 acts as an epigenetic transcriptional modulator essential for repressing ERVs in trophoblasts, ensuring normal pregnancy and fetal survival, which sheds new light on potential epigenetic causes contributing to RM.

[Limited internal fixation combined with a hinged external fixator in treatment of peri-elbow bone infection].

Objective: To evaluate the effectiveness of limited internal fixation combined with a hinged external fixator in the treatment of peri-elbow bone infection. Methods: The clinical data of 19 patients with peri-elbow bone infection treated with limited internal fixation combined with a hinged external fixator between May 2018 and May 2021 were retrospectively analyzed. There were 15 males and 4 females with an average age of 44.6 years (range, 28-61 years). There were 13 cases of distal humerus fractures and 6 cases of proximal ulna fractures. All the 19 cases were infected after internal fixation of fracture, and 2 cases were complicated with radial nerve injury. According to Cierny-Mader anatomical classification, 11 cases were type Ⅱ, 6 cases were type Ⅲ, and 2 cases were type Ⅳ. The duration of bone infection was 1-3 years. After primary debridement, the bone defect was (3.04±0.28) cm, and the antibiotic bone cement was implanted into the defect area, and the external fixator was installed; 3 cases were repaired with latissimus dorsi myocutaneous flap, and 2 cases were repaired with lateral brachial fascial flap. Bone defects repair and reconstruction were performed after 6-8 weeks of infection control. The wound healing was observed, and white blood cell (WBC), erythrocyte sedimentation rate (ESR), and C-reaction protein (CRP) were reexamined regularly after operation to evaluate the infection control. X-ray films of the affected limb were taken regularly after operation to observe the bone healing in the defect area. At last follow-up, the flexion and extension range of motion and the total range of motion of the elbow joint were observed and recorded, and compared with those before operation, and the function of the elbow joint was evaluated by Mayo score. Results: All patients were followed up 12-34 months (mean, 26.2 months). The wounds healed in 5 cases after skin flap repair. Two cases of recurrent infection were effectively controlled by debridement again and replacement of antibiotic bone cement. The infection control rate was 89.47% (17/19) in the first stage. Two patients with radial nerve injury had poor muscle strength of the affected limb, and the muscle strength of the affected limb recovered from grade Ⅲ to about grade Ⅳ after rehabilitation exercise. During the follow-up period, there was no complication such as incision ulceration, exudation, bone nonunion, infection recurrence, or infection in the bone harvesting area. Bone healing time ranged from 16 to 37 weeks, with an average of 24.2 weeks. WBC, ESR, CRP, PCT, and elbow flexion, extension, and total range of motions significantly improved at last follow-up ( P<0.05). According to Mayo elbow scoring system, the results were excellent in 14 cases, good in 3 cases, and fair in 2 cases, and the excellent and good rate was 89.47%. Conclusion: Limited internal fixation combined with a hinged external fixator in the treatment of the peri-elbow bone infection can effectively control infection and restore the function of the elbow joint.

[Effect of dimethyloxalylglycine on angiogenesis in Choke â ¡ zone of cross-zone perforator flap and its mechanism].

OBJECTIVE: To study the effect of dimethyloxalylglycine (DMOG) on angiogenesis in Choke Ⅱ zone of rats cross-zone perforator flaps and its mechanism. METHODS: One hundred and twenty-six adult male Sprague Dawley rats were randomly divided into DMOG group, YC-1 group, and control group, with 42 rats in each group. Cross-zone perforator flap model with size of 12 cm×3 cm was made on the back of rats in the three groups. DMOG group was intraperitoneally injected with DMOG (40 mg/kg) at 1 day before operation, 2 hours before operation, and 1, 2, and 3 days after operation; YC-1 group and control group were intraperitoneally injected with YC-1 (10 mg/kg) and the same amount of normal saline at the same time points, respectively. The survival of flap was observed after operation. At 7 days after operation, the survival area of flap in each group was measured and the survival rate of flap was calculated. Flap transmittance test, gelatin-lead oxide angiography, and HE staining were used to observed the angiogenesis in the Choke Ⅱ zone of flaps in each group. Immunohistochemical staining and Western blot were used to detect the expressions of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor 1α (HIF-1α) in Choke Ⅱ zone of flaps in each group. The expressions of VEGF and HIF-1α were also determined by ELISA at 3, 5, and 7 days. RESULTS: At 7 days after operation, there was no obvious necrosis at the distal end of the flap in DMOG group, while necrosis occurred in both the control group and YC-1 group, mainly located at the distal end. The flap survival rate of DMOG group was 90.28%±1.37%, which was significantly higher than that of YC-1 group (84.28%±1.45%) and control group (85.83%±1.60%) ( P<0.05). DMOG group had more angiogenesis in Choke Ⅱ zone and the vascular structure was clear and complete. In YC-1 group and control group, the vessels in Choke Ⅱ zone was less and the vascular structure was disordered. The number of vessels was (25.56±1.29)/field in the DMOG group, which was significantly higher than that in the YC-1 group [(7.38±0.54)/field] and the control group [(14.48±0.91)/field] ( P<0.05). At 3, 5, and 7 days after operation, HIF-1α and VEGF expressions in ChokeⅡzone of DMOG group were significantly higher than those in YC-1 group and control group ( P<0.05). CONCLUSION: DMOG can promote angiogenesis in Choke Ⅱ zone, accelerate the early angiogenesis of the flap, improve the microcirculation and blood supply in the potential zone of the flap, reduce the injury of flap ischemia and hypoxia, and increase the survival rate of the flap.

Lack of MOF Decreases Susceptibility to Hypoxia and Promotes Multidrug Resistance in Hepatocellular Carcinoma via HIF-1α.

Hypoxia-inducible factor-1α (HIF-1α) promotes oncogenesis in hepatocellular carcinoma and is functionally linked to cell proliferation, chemoresistance, metastasis and angiogenesis. It has been confirmed that the low expression level of Males absent on the first (MOF) in hepatocellular carcinoma leads to poor prognosis of patients. However, potential regulatory mechanisms of MOF in response to hypoxia remain elusive. Our results demonstrate that MOF expression is negatively associated with HIF-1α expression in hepatocellular carcinoma tissues and in response to chloride-mimicked hypoxia in hepatocellular carcinoma cell lines. MOF regulates HIF-1α mRNA expression and also directly binds to HIF-1α to mediate HIF-1α N-terminal lysine acetylation, ubiquitination and degradation, with downstream effects on MDR1 levels. Functional inactivation of MOF enhances HIF-1α stability and causes cell tolerance to hypoxia that is insensitive to histone deacetylase inhibitor treatment. Dysfunction of MOF in hepatocellular carcinoma cells also results in chemoresistance to trichostatin A, sorafenib and 5-fluorouracil via HIF-1α. Our results suggest that MOF regulates hypoxia tolerance and drug resistance in hepatocellular carcinoma cells by modulating both HIF-1α mRNA expression and N-terminal acetylation of HIF-1α, providing molecular insight into MOF-dependent oncogenic function of hepatocellular carcinoma cells.

Mof regulates glucose level via altering different α-cell subset mass and intra-islet glucagon-like peptide-1, glucagon secretion.

BACKGROUND: Males absent on the first (Mof) is implicated in gene control of diverse biological processes, such as cell growth, differentiation, apoptosis and autophagy. However, the relationship between glucose regulation and Mof-mediated transcription events remains unexplored. We aimed to unravel the role of Mof in glucose regulation by using global and pancreatic α-cell-specific Mof-deficient mice in vivo and α-TC1-6 cell line in vitro. METHODS: We used tamoxifen-induced temporal Mof-deficient mice first to show Mof regulate glucose homeostasis, islet cell proportions and hormone secretion. Then we used α-cell-specific Mof-deficient mice to clarify how α-cell subsets and ß-cell mass were regulated and corresponding hormone level alterations. Ultimately, we used small interfering RNA (siRNA) to knockdown Mof in α-TC1-6 and unravel the mechanism regulating α-cell mass and glucagon secretion. RESULTS: Mof was mainly expressed in α-cells. Global Mof deficiency led to lower glucose levels, attributed by decreased α/ß-cell ratio and glucagon secretion. α-cell-specific Mof-deficient mice exhibited similar alterations, with more reduced prohormone convertase 2 (PC2)-positive α-cell mass, responsible for less glucagon, and enhanced prohormone convertase 1 (PC1/3)-positive α-cell mass, leading to more glucagon-like peptide-1 (GLP-1) secretion, thus increased ß-cell mass and insulin secretion. In vitro, increased DNA damage, dysregulated autophagy, enhanced apoptosis and altered cell fate factors expressions upon Mof knockdown were observed. Genes and pathways linked to impaired glucagon secretion were uncovered through transcriptome sequencing. CONCLUSION: Mof is a potential interventional target for glucose regulation, from the aspects of both α-cell subset mass and glucagon, intra-islet GLP-1 secretion. Upon Mof deficiency, Up-regulated PC1/3 but down-regulated PC2-positive α-cell mass, leads to more GLP-1 and insulin but less glucagon secretion, and contributed to lower glucose level.

Identification and characterization of interferon regulatory factor 1 from Lateolabrax japonicus involved in antiviral immune response against grouper nervous necrosis virus infection.

Interferon regulatory factors (IRFs) play a key role in mediating the host response against pathogen infection and other important biological processes. In the present study, an interferon regulation factor 1 gene was identified from Lateolabrax japonicus (designated LjIRF-1), the cDNA sequence of LjIRF-1 was 1394 bp long, and with an open reading frame (ORF) of 945 bp that encodes a peptide of 314 amino acids. Bioinformatics data showed that LjIRF-1 possesses a DNA-binding domain (DBD) and two low complexity regions, which shared 56-81% identity to other fish IRF-1s. The LjIRF-1 transcripts were detectable in all examined tissues of healthy L. japonicus, with higher levels in the blood, head-kidney, intestine, gill and spleen. When challenged with grouper nervous necrosis virus (GNNV) and poly (I:C) infection, both the mRNA expression levels of LjIRF-1 and L. japonicus interferon-1 gene (designated LjIFN-1) were significantly up-regulated. Furthermore, like with poly (I:C), the active purified recombinant protein (rLjIRF-1) was also capable of increasing the expression level of LjIFN-1; controlling the copy number of GNNV under lethiferous titer (1011-1012 copies/µL) and promoting the survival rate of GNNV infected L. japonicas. Combine all the results, we deduced that LjIRF-1 is involved in defending GNNV infection by simulating LjIFN-1 signal pathway in L. japonicas.