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Photosynthetic organisms have developed mechanisms to regulate light reactions in response to varying light conditions. Photosynthetic electron transport leads to the formation of a ΔpH across the thylakoid membrane, which is crucial for regulating electron transport. However, other pH modulators remain to be identified, particularly in cyanobacteria. In this study, we evaluated the potential involvement of six Na+/H+ antiporters (NhaS1-NhaS6) in control of pH in the cyanobacterium Synechocystis sp. PCC 6803. Synechocystis showed a strong requirement for Na+ at high light intensities, with ΔnhaS1 and ΔnhaS2 strains unable to grow under high light conditions. We analyzed Na+ efflux-driven H+-uptake activities of NhaS1-NhaS6 in inverted membranes of Escherichia coli. Biological fractionation and immunoelectron microscopy revealed that NhaS1 localizes to both the plasma and thylakoid membranes while NhaS2 localizes to the plasma membrane. Measurement of photosynthesis activity indicated that NhaS2 promotes ATP production and electron transport from PQ to P700. Measurements of pH outside of the cells and in the cytoplasm suggested that both NhaS1 and NhaS2 are involved in plasma membrane-mediated light-dependent H+ uptake and cytoplasmic acidification. NhaS1 and NhaS2 were also found to prevent photoinhibition under high light treatment. These results indicate that H+ transport mediated by NhaS1 and NhaS2 plays a role in regulating intracellular pH and maintaining photosynthetic electron transport., (© The Author(s) 2024. Published by Oxford University Press on behalf of American Society of Plant Biologists.)

Saccharomyces cerevisiae Mdm38 and Ylh47 are homologs of the Ca 2+ /H + antiporter Letm1, a candidate gene for seizures associated with Wolf-Hirschhorn syndrome in humans. Mdm38 is important for K + /H + exchange across the inner mitochondrial membrane and contributes to membrane potential formation and mitochondrial protein translation. Ylh47 also localizes to the inner mitochondrial membrane. However, knowledge of the structures and detailed transport activities of Mdm38 and Ylh47 is limited. In this study, we conducted characterization of the ion transport activities and related structural properties of Mdm38 and Ylh47. Growth tests using Na + /H + antiporter-deficient Escherichia coli strain TO114 showed that Mdm38 and Ylh47 had Na + efflux activity. Measurement of transport activity across E. coli -inverted membranes showed that Mdm38 and Ylh47 had K + /H + , Na + /H + , and Li + /H + antiport activity, but unlike Letm1, they lacked Ca 2+ /H + antiport activity. Deletion of the ribosome-binding domain resulted in decreased Na + efflux activity in Mdm38. Structural models of Mdm38 and Ylh47 identified a highly conserved glutamic acid in the pore-forming membrane-spanning region. Replacement of this glutamic acid with alanine, a non-polar amino acid, significantly impaired the ability of Mdm38 and Ylh47 to complement the salt sensitivity of E. coli TO114. These findings not only provide important insights into the structure and function of the Letm1-Mdm38-Ylh47 antiporter family but by revealing their distinctive properties also shed light on the physiological roles of these transporters in yeast and animals., Importance: The inner membrane of mitochondria contains numerous ion transporters, including those facilitating H + transport by the electron transport chain and ATP synthase to maintain membrane potential. Letm1 in the inner membrane of mitochondria in animals functions as a Ca 2+ /H + antiporter. However, this study reveals that homologous antiporters in mitochondria of yeast, Mdm38 and Ylh47, do not transport Ca 2+ but instead are selective for K + and Na + . Additionally, the identification of conserved amino acids crucial for antiporter activity further expanded our understanding of the structure and function of the Letm1-Mdm38-Ylh47 antiporter family., Competing Interests: The authors declare no conflict of interest.

Background: Malignant chest wall tumors need to be excised with wide resection to ensure tumor free margins, and the reconstruction method should be selected according to the depth and dimensions of the tumor. Vascularized tissue is needed to cover the superficial soft tissue defect or bone tissue defect. This study evaluated differences in complications according to reconstruction strategy., Methods: Forty-five patients with 52 operations for resection of malignant tumors in the chest wall were retrospectively reviewed. Patients were categorized as having superficial tumors, comprising Group A with simple closure for small soft tissue defects and Group B with flap coverage for wide soft tissue defects, or deep tumors, comprising Group C with full-thickness resection with or without mesh reconstruction and Group D with full-thickness resection covered by flap with or without polymethyl methacrylate. Complications were evaluated for the 52 operations based on reconstruction strategy then risk factors for surgical and respiratory complications were elucidated., Results: Total local recurrence-free survival rates in 45 patients who received first operation were 83.9% at 5 years and 70.6% at 10 years. The surgical complication rate was 11.5% (6/52), occurring only in cases with deep tumors, predominantly from Group D. Operations needing chest wall reconstruction (p = 0.0016) and flap transfer (p = 0.0112) were significantly associated with the incidence of complications. Operations involving complications showed significantly larger tumors, wider areas of bony chest wall resection and greater volumes of bleeding (p < 0.005). Flap transfer was the only significant predictor identified from multivariate analysis (OR: 10.8, 95%CI: 1.05-111; p = 0.0456). The respiratory complication rate was 13.5% (7/52), occurring with superficial and deep tumors, particularly Groups B and D. Flap transfer was significantly associated with the incidence of respiratory complications (p < 0.0005). Cases in the group with respiratory complications were older, more frequently had a history of smoking, had lower FEV1.0% and had a wider area of skin resected compared to cases in the group without respiratory complications (p < 0.05). Preoperative FEV1.0% was the only significant predictor identified from multivariate analysis (OR: 0.814, 95%CI: 0.693-0.957; p = 0.0126)., Conclusions: Surgical complications were more frequent in Group D and after operations involving flap transfer. Severe preoperative FEV1.0% was associated with respiratory complications even in cases of superficial tumors with flap transfer., (© 2024. The Author(s).)

Purpose: An optimal radiotherapy field for superficial esophageal carcinoma is yet to be established. We evaluated the long-term outcomes and recurrence patterns of involved-field radiotherapy (IFRT) in older patients with superficial thoracic esophageal squamous cell carcinoma (ESCC)., Materials and Methods: Fifty-four patients (49 men and 5 women; mean age, 77 [range: 66-90] years) who underwent IFRT for superficial thoracic ESCC between January 2003 and January 2019 were retrospectively reviewed. Concurrent chemotherapy was administered at the discretion of the attending physician. The primary endpoint was overall survival. The secondary endpoints were progression-free survival and complete response rate., Results: The tumors were localized in the upper, middle, and lower thoracic esophagus in 2, 40, and 12 patients, respectively. All patients underwent IFRT using anteroposterior and anterior-posterior oblique opposed beams (off-cord). The prescribed total doses were 50.4, 59.4-61.2, and 66-70 Gy for 6, 40, and 8 patients, respectively. Concurrent chemotherapy was administered to 33 patients. The median follow-up duration was 57 months. The median overall survival was 115 months. The 5-year overall and progression-free survival rates were 71.7% and 60.1%, respectively. Forty-nine patients had a complete response at one month after IFRT (complete response rate: 90.7%). Twenty patients had recurrence; there were 13 in-field and 7 out-of-field recurrence cases. The radiation-related adverse events were generally mild. Grade 3 late toxicity was observed in one patient., Conclusions: The efficacy of IFRT was suggested to be comparable to that of standard treatments. Therefore, IFRT can be a promising approach for treating superficial ESCC in older adults, especially those with severe comorbidities., (© 2024. The Author(s).)

Introduction: Musculoskeletal transfer for chest wall tissue defects is a crucial method, and pedicled flaps around the chest wall are preferred in terms of location and simplicity of transfer. These require special care because of complications such as partial necrosis, fistula, wound dehiscence, infection, hematoma and restricted function of the arm or shoulder. However, studies of respiratory function are rare. In the present study, we investigated the complications including respiratory problems after wide resection for malignant chest wall tumors with musculoskeletal pedicle transfer., Methods: A total of 13 patients (15 operations) who underwent wide resection of primary, recurrent, or metastatic malignant chest wall tumors and musculoskeletal pedicle transfer for coverage of tissue defects were enrolled in the present study. A retrospective review of all patients was performed using data collected from hospital records and follow-up information. The complications of musculoskeletal transfer after chest wall wide resection, including respiratory problems, are evaluated., Results: Rib or sternal resection was performed in 12 operations, and only soft tissue resection was performed in 3 operations. Latissimus dorsi (LD) pedicle transfer was performed in 13 operations, and pectoralis major (PM) pedicle transfer was performed in 2 operations; basically, wounds were closed primarily. Surgical complications were observed following 5 of the 15 operations (33.3%). Respiratory complications were seen in 7 of the 15 operations (46.7%). Patients with respiratory complications showed significantly lower preoperative FEV1.0% values than those without respiratory complications ( p  = 0.0196). Skin resection area tended to be higher in the complication group than in the no complication group ( p  = 0.104)., Discussion: Pedicled myocutaneous flap transfers such as LD, PM, and rectus abdominus can be used following multiple resections. After harvesting LD or PM, the wound can be closed primarily for an 8-10-cm skin defect in patients with normal respiratory function. However, for patients with low FEV1.0%, after primary closure of LD or PM transfer for wide soft tissue defects, attention should be paid to postoperative respiratory complications., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2024 Asanuma, Tsujii, Hagi, Nakamura, Uchiyama, Adachi, Nakata, Kataoka and Sudo.)

Background: Previous studies have suggested that response-style strategies (rumination, problem-solving, and distraction) can be risk or protective factors for the development of abnormal eating behaviors/attitudes (AEB) during adolescence. However, due to limited empirical data regarding the prospective effects of these strategies on AEB, further research is needed to clarify their role in developing AEB in adolescence., Methods: This study investigated the one-year lagged effects of response-style strategies on AEB in 24,883 fourth- to eighth-grade students in Japan between 2015 and 2019 using a cross-lagged panel model. Depressive symptoms and body mass index (BMI), which are reported to relate to AEB, were also included in the analytic model. The students self-reported their levels of response-style strategies, AEB, and depressive symptoms. We also evaluated BMI based on teachers' reports., Results: We found that greater rumination significantly predicted more severe AEB in the following year among students from all grades, with small to moderate effect sizes. In addition, distraction significantly predicted more severe binge eating/purging behaviors, but with very weak small effect sizes. Problem-solving did not predict any level of AEB. Furthermore, we observed significant reciprocal relationships between response-style strategies, AEB, and depressive symptoms. Positive reciprocal associations between BMI and AEB were also found except for some intervals., Conclusions: We concluded that a decrease in rumination is critical to alleviating mental health problems, such as AEB and depressive symptoms, during adolescence. This suggests that interventions to reduce the level of rumination should be conducted in the early stages of adolescence., Trial Registration Number: Not Applicable., (© 2024. The Author(s).)

The osmotic stress imposed on microorganisms by hypotonic conditions is perceived to regulate water and solute flux via cell membranes, which are crucial for survival. Some cells that fail to perceive osmotic stress die because this results in the rupture of the cell membrane. The flux through the membrane is characterized by the membrane permeability, which is measured using a stopped-flow apparatus in response to a millisecond-order osmolarity change. However, the obtained data are an ensemble average of each cell response. Additionally, the measurement of permeability, considering cellular viability, contributes to a more accurate evaluation of osmoadaptation. Here, we present a novel on-chip instantaneous extracellular solution exchange method using an air-liquid interface. The presented method provides a concurrent evaluation at the single-cell level in response to a millisecond-order osmotic shock, considering cellular viability by solution exchange. This method utilizes a liquid bridge with a locally formed droplet on the surface of a micropillar fabricated inside a microchannel. We evaluated a solution exchange time of 3.6 ms and applied this method to Synechocystis PCC 6803 under two different osmolarity conditions. The live/dead ratio of 1 M to 0.5 M osmotic down shock condition was 78.8/21.2% while that of 1 M to 0.25 M osmotic down shock condition was 40.0/60.0%. We evaluated the water permeability of two groups: cells that were still live before and after osmotic shock (hereafter named cell type 1), and cells that were live before but were dead 10 minutes after osmotic shock (hereafter named cell type 2). The results indicated that the water permeability of cell type 2 was higher than that of cell type 1. The results obtained using the presented methods confirmed that the effect of osmotic stress can be accurately evaluated using single-cell analysis.

The integration of liquid exchange and microfluidic chips plays a critical role in the biomedical and biophysical fields as it enables the control of the extracellular environment and allows for the simultaneous stimulation and detection of single cells. In this study, we present a novel approach for measuring the transient response of single cells using a system integrated with a microfluidic chip and a probe with a dual pump. The system was composed of a probe with a dual pump system, a microfluidic chip, optical tweezers, an external manipulator, an external piezo actuator, etc. Particularly, we incorporated the probe with the dual pump to allow for high-speed liquid change, and the localized flow control enabled a low disturbance contact force detection of single cells on the chip. Using this system, we measured the transient response of the cell swelling against the osmotic shock with a very fine time resolution. To demonstrate the concept, we first designed the double-barreled pipette, which was assembled with two piezo pumps to achieve a probe with the dual pump system, allowing for simultaneous liquid injection and suction. The microfluidic chip with on-chip probes was fabricated, and the integrated force sensor was calibrated. Second, we characterized the performance of the probe with the dual pump system, and the effect of the analysis position and area of the liquid exchange time was investigated. In addition, we optimized the applied injection voltage to achieve a complete concentration change, and the average liquid exchange time was achieved at approximately 3.33 ms. Finally, we demonstrated that the force sensor was only subjected to minor disturbances during the liquid exchange. This system was utilized to measure the deformation and the reactive force of Synechocystis sp. strain PCC 6803 in osmotic shock, with an average response time of approximately 16.33 ms. This system reveals the transient response of compressed single cells under millisecond osmotic shock which has the potential to characterize the accurate physiological function of ion channels.

Salinity stress can greatly reduce seed production because plants are especially sensitive to salt during their reproductive stage. Here, we show that the sodium ion transporter AtHKT1;1 is specifically expressed around the phloem and xylem of the stamen in Arabidopsis thaliana to prevent a marked decrease in seed production caused by salt stress. The stamens of AtHKT1;1 mutant under salt stress overaccumulate Na + , limiting their elongation and resulting in male sterility. Specifically restricting AtHKT1;1 expression to the phloem leads to a 1.5-fold increase in the seed yield upon sodium ion stress. Expanding phloem expression of AtHKT1;1 throughout the entire plant is a promising strategy for increasing plant productivity under salinity stress.

Phototrophic bacteria face diurnal variations of environmental conditions such as light and osmolarity that affect their carbon metabolism and ability to generate organic compounds. The model cyanobacterium, Synechocystis sp. PCC 6803 forms a biofilm when it encounters extreme conditions like high salt stress, but the molecular mechanisms involved in perception of environmental changes that lead to biofilm formation are unknown. Here, we studied two two-component regulatory systems (TCSs) that contain diguanylate cyclases (DGCs), which produce the second messenger c-di-GMP, as potential components of the biofilm-inducing signaling pathway in Synechocystis. Analysis of single mutants provided evidence for involvement of the response regulators, Rre2 and Rre8 in biofilm formation. A bacterial two-hybrid assay showed that Rre2 and Rre8 each formed a TCS with a specific histidine kinase, Hik12 and Hik14, respectively. The in vitro assay showed that Rre2 had DGC activity regardless of its de/phosphorylation status, whereas Rre8 required phosphorylation for DGC activity. Hik14-Rre8 likely functioned as an inducible sensing system in response to environmental change. Biofilm assays with Synechocystis mutants suggested that pairs of hik12-rre2 and hik14-rre8 responded to high salinity-induced biofilm formation. Inactivation of hik12-rre2 and hik14-rre8 did not affect the performance of the light reactions of photosynthesis. These data suggest that Hik12-Rre2 and Hik14-Rre8 participate in biofilm formation in Synechocystis by regulating c-di-GMP production via the DGC activity of Rre2 and Rre8., (© 2023 The Authors. Molecular Microbiology published by John Wiley & Sons Ltd.)

Background: Chest wall malignant tumor (including primary and metastatic lesions) is rare, representing less than 5% of all thoracic malignancies. Local control of chest wall malignancies requires wide resection with tumor-free margins. These requirements increase the risk of thoracic cavity failure and subsequent pulmonary failure. The restoration strategy for chest wall defects comprises chest wall reconstruction and soft-tissue coverage. Various reconstruction methods have been used, but both evidence and guidelines for chest wall reconstruction remain lacking. The purposes of this study were to collate our institutional experience, evaluate the outcomes of full-thickness chest wall resection and reconstruction for patients with chest wall malignant tumor, and identify problems in current practice for chest wall reconstruction with a focus on local control, complications, pulmonary function and scoliosis., Methods: Participants comprised 30 patients with full-thickness chest wall malignant tumor who underwent chest wall resection and reconstruction between 1997 and 2021 in Mie University Hospital. All patients underwent chest wall resection of primary, recurrent or metastatic malignant tumors. A retrospective review was conducted for 32 operations., Results: Recurrence was observed after 5 operations. Total 5-year recurrence-free survival (RFS) rate was 79.3%. Diameter ≥5 cm was significantly associated with poor RFS. The postoperative complication rate was 18.8%. Flail chest was observed with resection of ≥3 ribs in anterior and lateral resections or with sternum resection without polyethylene methylmethacrylate reconstruction. Postoperative EFV1.0% did not show any significant decrease. Postoperative %VC decreased significantly with resection of ≥4 ribs or an area of >70 cm2. Postoperative scoliosis was observed in 8 of 28 patients. Posterior resection was associated with a high prevalence of scoliosis (88.9%)., Conclusion: With chest wall reconstruction, risks of pulmonary impairment, flail chest and scoliosis were significantly increased. New strategies including indications for rigid reconstruction are needed to improve the outcomes of chest wall reconstruction., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Asanuma, Tsujii, Hagi, Nakamura, Kita, Shimamoto, Kataoka, Takao and Sudo.)

Defects occur in laser powder bed fusion (L-PBF) such as the keyholing, lack of fusion, and the balling depending on the laser power ( P ) and the scan speed ( V ). The figure shows that the occupied regions of each defect are the process window and are essentially important to fabricate a high-quality part. This paper is a study of process window generation using single-track experiments and finite-element method simulation of thermal conduction for Inconel738LC alloy. A series of single-track experiments were conducted varying the range of P and V and the results were classified into keyholing, lack of fusion, balling, and good track. A series of simulations were conducted and validated by comparison with the experiments. To quantitively identify the balling, the isolines from the contour map generated by the results of simulations and the balling criteria of the ratio of melt pool length and the depth ( L / D ) of 7.69 were determined considering the past theoretical studies. The lack of fusion criteria: the ratio of the overlap depth in fabrication using multi-scan ( D ov ) and powder layer thickness ( t ) of 0.1 was obtained. Using the criteria obtained from the experiments and simulation, the process window was generated.

Escherichia coli K-12 possesses two versions of Trk/Ktr/HKT-type potassium ion (K + ) transporters, TrkG and TrkH. The current paradigm is that TrkG and TrkH have largely identical characteristics, and little information is available regarding their functional differences. Here, we show using cation uptake experiments with K + transporter knockout mutants that TrkG and TrkH have distinct ion transport activities and physiological roles. K + -transport by TrkG required Na + , whereas TrkH-mediated K + uptake was not affected by Na + . An aspartic acid located five residues away from a critical glycine in the third pore-forming region might be involved in regulation of Na + -dependent activation of TrkG. In addition, we found that TrkG but not TrkH had Na + uptake activity. Our analysis of K + transport mutants revealed that TrkH supported cell growth more than TrkG; however, TrkG was able to complement loss of TrkH-mediated K + uptake in E. coli. Furthermore, we determined that transcription of trkG in E. coli was downregulated but not completely silenced by the xenogeneic silencing factor H-NS (histone-like nucleoid structuring protein or heat-stable nucleoid-structuring protein). Taken together, the transport function of TrkG is clearly distinct from that of TrkH, and TrkG seems to have been accepted by E. coli during evolution as a K + uptake system that coexists with TrkH., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

A man in his 60s had end-stage alcoholic cirrhosis. About six months before his death, hepatic peribiliary cysts (HPBC) rapidly increased, and he developed jaundice and liver failure. The pathological autopsy performed after his death revealed that his intrahepatic bile duct was pressured due to multiple cysts caused by HPBC, which resulted in liver failure. Some cases of HPBC have been associated with alcoholic cirrhosis;however, no other cases of increased HPBC in a short period of time have been reported. Although identifying the cause of increased HPBC in a short time is difficult in this case, it may be have been caused by continuous alcohol drinking after the onset of HPBC. Most patients with HPBC have liver cirrhosis and obstructive jaundice that may promote liver failure as in this case. Therefore, patients with HPBC should not only be instructed for abstinence but also promptly consider effective treatments in the event of obstructive jaundice to prevent liver dysfunction.

Predators can cause selection that drives the evolution of various anti-predator defenses in prey 1 , 2 , 3 . Some prey species have evolved specific defensive devices, while others simply use body parts that evolved for reasons other than defense to repel predators 1 . For example, many animal species have strong canine teeth or mandibles to kill prey and to counterattack their enemies 1 , 2 , 3 . Bees and wasps (Insecta: Hymenoptera) use their ovipositors as stings to repel attackers, including humans 4 . Stinging by injecting venom can cause intense pain and allergic reactions in humans 4 . Therefore, stinging hymenopterans that are recognized as dangerous have evolved warning signals, such as conspicuous body coloration 4 . Hymenopteran males, which lack ovipositors, are believed to be harmless, and the males avoid predators by mimicking the females' coloration and behavior 4 . Here, we report that males of the mason wasp Anterhynchium gibbifrons (Hymenoptera: Vespidae: Eumeninae) use sharp genital spines to counterattack predators. A potential predator, the tree frog Dryophytes japonica (= Hyla japonica) (Anura: Hylidae) or the pond frog Pelophylax nigromaculatus (Anura: Ranidae), was housed with male A. gibbifrons under laboratory conditions. All tree and pond frogs attacked the male wasps. Although all of the pond frogs ate the male wasps, 35.3% of the tree frogs ultimately rejected them. Male wasps were frequently observed to pierce the mouth or other parts of frogs with their genitalia while being attacked. The tree frogs were also housed with male wasps from which the genitalia were removed. All these frogs ate the genitalia-less males. Therefore, male wasps used their genitalia to prevent tree frogs from swallowing them. This study highlights the importance of male genitalia as an anti-predator defense and provides a new perspective for understanding the ecological roles of male genitalia in animals., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The rotator cuff (RC) is frequently torn at the enthesis composed of fibrocartilage. We aimed to histopathologically evaluate lining layers and assess the distribution of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)4, ADAMTS5, and microRNA (miR)-140s in the synovia of patients with RC tears. We recruited 51 patients who underwent arthroscopic surgical treatment for full-thickness rotator cuff tears, including 26 patients with < 3 cm tear size (group N) and 25 patients with ≥ 3 cm tear size (group W). Biopsied synovia were analyzed using histological and immunohistological techniques for the presence ADAMTS4 and ADAMTS5. The layers of the synovial lining were morphologically classified into 3 grades according to the synovitis score and staining levels of ADAMTSs. The glenohumeral synovia from 8 patients with recurrent shoulder dislocation (group C) were used as controls. Furthermore, in situ hybridization was performed to evaluate the presence of miR-140s in patients with massive tears and recurrent shoulder dislocation. The staining levels were evaluated and analyzed based on comparison between patient groups and correlation between ADAMTS5 and miR-140s. Histological analysis revealed significant differences between groups W and C. ADAMTS5 and ADAMTS4 were strongly expressed in the synovial lining of patients in group W, and this expression was significantly higher than that in groups C and N. In addition, expression of ADAMTS5 was inversely correlated with that of miR-140-3p. This study showed that synovia from group W had a significantly higher rate of severely thickened areas with strong expression of both aggrecanases. Furthermore, the area with weak expression of miR-140-3p showed strong ADAMTS5 expression., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Ischemia-reperfusion (I/R) injury is a major contributor to skin flap necrosis, which is a serious complication of reconstructive surgery. The purpose of this study was to evaluate the protective effect of treatment with febuxostat, a selective xanthine oxidase inhibitor, on I/R injury in the skin flap of an animal (rat) model., Methods: Superficial epigastric flaps were raised in Sprague-Dawley rats and subjected to ischemia for 3 h. Febuxostat at a dose of 10 mg/kg/day was administered to rats in drinking water from 1 week before the surgery (Feb group). Control animals received no drugs (Con group). The mean ratio of flap survival and contraction was evaluated and compared between animals with and without administration of febuxostat on day 5 after the surgery. In addition, infiltration by polymorphonuclear leukocytes and muscles of the panniculus carnosus in the flap were histologically evaluated using hematoxylin-eosin staining. Furthermore, xanthine oxidase activity, ATP levels, superoxide dismutase activity, and expression of 8-hydroxy-2'-deoxyguanosine (8-OHdG), tumor necrosis factor-α, and interleukin-1β were quantitatively assessed in the skin flap 24 h after the surgery., Results: In the Feb group, the survival and contraction rates at the 5 d timepoint post-surgery were significantly higher and lower than those in the Con group, respectively. Histological analysis showed significant reduction in polymorphonuclear leukocyte infiltration and muscle injury scores due to I/R injury in the Feb group. The expression of 8-OHdG was also significantly inhibited in animals administered febuxostat. Biochemical analysis showed a significant reduction in xanthine oxidase activity and significant increases in ATP levels and superoxide dismutase activity in the Feb group. Furthermore, the expression of interleukin-1β was significantly lower in the Feb group than in the Con group., Conclusion: Febuxostat, which is clinically used for the treatment of hyperuricemia, was effective against necrosis of the skin flap via inhibition of oxidative stress and inflammation caused by I/R injury., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Recent evidence has documented the potential roles of histone-modifying enzymes in autism-spectrum disorder (ASD). Aberrant histone H3 lysine 9 (H3K9) dimethylation resulting from genetic variants in histone methyltransferases is known for neurodevelopmental and behavioral anomalies. However, a systematic examination of H3K9 methylation dynamics in ASD is lacking. Here we resequenced nine genes for histone methyltransferases and demethylases involved in H3K9 methylation in individuals with ASD and healthy controls using targeted next-generation sequencing. We identified a novel rare variant (A211S) in the SUV39H2, which was predicted to be deleterious. The variant showed strongly reduced histone methyltransferase activity in vitro. In silico analysis showed that the variant destabilizes the hydrophobic core and allosterically affects the enzyme activity. The Suv39h2-KO mice displayed hyperactivity and reduced behavioral flexibility in learning the tasks that required complex behavioral adaptation, which is relevant for ASD. The Suv39h2 deficit evoked an elevated expression of a subset of protocadherin β (Pcdhb) cluster genes in the embryonic brain, which is attributable to the loss of H3K9 trimethylation (me3) at the gene promoters. Reduced H3K9me3 persisted in the cerebellum of Suv39h2-deficient mice to an adult stage. Congruently, reduced expression of SUV39H1 and SUV39H2 in the postmortem brain samples of ASD individuals was observed, underscoring the role of H3K9me3 deficiency in ASD etiology. The present study provides direct evidence for the role of SUV39H2 in ASD and suggests a molecular cascade of SUV39H2 dysfunction leading to H3K9me3 deficiency followed by an untimely, elevated expression of Pcdhb cluster genes during early neurodevelopment., (© 2021. The Author(s), under exclusive licence to Springer Nature Limited.)