Fluoride-treated rare earth-free magnesium alloy ZK30: An inert and bioresorbable material for bone fracture treatment devices

Bone fractures represent a common health problem, particularly in an increasingly aging population. Bioresorbable magnesium (Mg) alloy-based implants offer promising alternatives to traditional metallic implants for the treatment of bone fractures because they eliminate the need for implant removal after healing. The Mg-Y-rare-earth (RE)-Zr alloy WE43, designed for orthopedic implants, has received European Conformity mark approval. However, currently, WE43 is not clinically used in certain countries possibly because of concerns related to RE metals. In this study, we investigated the use of a RE-free alloy, namely, Mg-Zn-Zr alloy (ZK30), as an implant for bone fractures. Hydrofluoric acid (HF) treatment was performed to improve the corrosion resistance of ZK30. HF-treated ZK30 (HF-ZK30) exhibited lower corrosion rate and higher biocompatibility than those of WE43 in in vitro experiments. After implanting a rod of HF-ZK30 into the fractured femoral bones of mice, HF-ZK30 held the bones and healed the fracture without deformation. Treatment results of HF-ZK30 were comparable to those of WE43, indicating the potential of HF-ZK30 as a bioresorbable and safe implant for bone repair.

Discretizing low-intensity whole-body vibration into bouts with short rest intervals promotes bone defect repair in osteoporotic mice

Continuous administration of low-intensity whole-body vibration (WBV) gradually diminishes bone mechanosensitivity over time, leading to a weakening of its osteogenic effect. We investigated whether discretizing WBV into bouts with short rest intervals was effective in enhancing osteoporotic bone repair. Ten-week-old female mice were ovariectomized and underwent drill-hole defect surgery (Day 0) on the right tibial diaphysis at 11 weeks of age. The mice underwent one of three regimens starting from Day 1 for 5 days/week: continuous WBV at 45 Hz and 0.3 g for 7.5 min/day (cWBV); 3-s bouts of WBV at 45 Hz, 0.3 g followed by 9-s rest intervals, repeated for 30 min/day (repeated bouts of whole-body vibration with short rest intervals [rWBV]); or a sham treatment. Both the cWBV and rWBV groups received a total of 20,250 vibration cycles per day. On either Day 7 or 14 posteuthanasia (n = 6/group/timepoint), the bone and angiogenic vasculature in the defect were computed tomography imaged using synchrotron light. By Day 14, the bone repair was most advanced in the rWBV group, showing a higher bone volume fraction and a more uniform mineral distribution compared with the sham group. The cWBV group exhibited an intermediate level of bone repair between the sham and rWBV groups. The rWBV group had a decrease in large-sized angiogenic vessels, while the cWBV group showed an increase in such vessels. In conclusion, osteoporotic bone repair was enhanced by WBV bouts with short rest intervals, which may potentially be attributed to the improved mechanosensitivity of osteogenic cells and alterations in angiogenic vasculature.

Hepatocytes differentiate into intestinal epithelial cells through a hybrid epithelial/mesenchymal cell state in culture

Hepatocytes play important roles in the liver, but in culture, they immediately lose function and dedifferentiate into progenitor-like cells. Although this unique feature is well-known, the dynamics and mechanisms of hepatocyte dedifferentiation and the differentiation potential of dedifferentiated hepatocytes (dediHeps) require further investigation. Here, we employ a culture system specifically established for hepatic progenitor cells to study hepatocyte dedifferentiation. We found that hepatocytes dedifferentiate with a hybrid epithelial/mesenchymal phenotype, which is required for the induction and maintenance of dediHeps, and exhibit Vimentin-dependent propagation, upon inhibition of the Hippo signaling pathway. The dediHeps re-differentiate into mature hepatocytes by forming aggregates, enabling reconstitution of hepatic tissues in vivo. Moreover, dediHeps have an unexpected differentiation potential into intestinal epithelial cells that can form organoids in three-dimensional culture and reconstitute colonic epithelia after transplantation. This remarkable plasticity will be useful in the study and treatment of intestinal metaplasia and related diseases in the liver.

Hypoxia- and Postirradiation reoxygenation-induced HMHA1/ARHGAP45 expression contributes to cancer cell invasion in a HIF-dependent manner

BACKGROUND

Cancer cells in severely hypoxic regions have been reported to invade towards tumour blood vessels after surviving radiotherapy in a postirradiation reoxygenation- and hypoxia-inducible factor (HIF)-dependent manner and cause recurrence. However, how HIF induces invasiveness of irradiated and reoxygenated cancer cells remains unclear.

METHODS

Here, we identified human minor histocompatibility antigen 1 (HMHA1), which has been suggested to function in cytoskeleton dynamics and cellular motility, as a responsible factor and elucidated its mechanism of action using molecular and cellular biology techniques.

RESULTS

HMHA1 expression was found to be induced at the transcription initiation level in a HIF-dependent manner under hypoxia. Boyden chamber invasion assay revealed that the induction of HMHA1 expression is required for the increase in invasion of hypoxic cancer cells. Reoxygenation treatment after ionising radiation in vitro that mimics dynamic changes of a microenvironment in hypoxic regions of tumour tissues after radiation therapy further enhanced HMHA1 expression and invasive potential of HMHA1 wildtype cancer cells in ROS- and HIF-dependent manners, but not of HMHA1 knockout cells.

CONCLUSION

These results together provide insights into a potential molecular mechanism of the acquisition of invasiveness by hypoxic cancer cells after radiotherapy via the activation of the ROS/HIF/HMHA1 axis.

Efficient hepatocyte differentiation of primary human hepatocyte-derived organoids using three dimensional nanofibers (HYDROX) and their possible application in hepatotoxicity research

Human liver organoids are in vitro three dimensionally (3D) cultured cells that have a bipotent stem cell phenotype. Translational research of human liver organoids for drug discovery has been limited by the challenge of their low hepatic function compared to primary human hepatocytes (PHHs). Various attempts have been made to develop functional hepatocyte-like cells from human liver organoids. However, none have achieved the same level of hepatic functions as PHHs. We here attempted to culture human liver organoids established from cryopreserved PHHs (PHH-derived organoids), using HYDROX, a chemically defined 3D nanofiber. While the proliferative capacity of PHH-derived organoids was lost by HYDROX-culture, the gene expression levels of drug-metabolizing enzymes were significantly improved. Enzymatic activities of cytochrome P450 3A4 (CYP3A4), CYP2C19, and CYP1A2 in HYDROX-cultured PHH-derived organoids (Org-HYDROX) were comparable to those in PHHs. When treated with hepatotoxic drugs such as troglitazone, amiodarone and acetaminophen, Org-HYDROX showed similar cell viability to PHHs, suggesting that Org-HYDROX could be applied to drug-induced hepatotoxicity tests. Furthermore, Org-HYDROX maintained its functions for up to 35 days and could be applied to chronic drug-induced hepatotoxicity tests using fialuridine. Our findings demonstrated that HYDROX could possibly be a novel biomaterial for differentiating human liver organoids towards hepatocytes applicable to pharmaceutical research.

Angiotensin II participates in mitochondrial thermogenic functions via the activation of glycolysis in chemically induced human brown adipocytes

Brown adipocytes are potential therapeutic targets for the prevention of obesity-associated metabolic diseases because they consume circulating glucose and fatty acids for heat production. Angiotensin II (Ang II) peptide is involved in the pathogenesis of obesity- and cold-induced hypertension; however, the mechanism underlying the direct effects of Ang II on human brown adipocytes remains unclear. Our transcriptome analysis of chemical compound-induced brown adipocytes (ciBAs) showed that the Ang II type 1 receptor (AGTR1), but not AGTR2 and MAS1 receptors, was expressed. The Ang II/AGTR1 axis downregulated the expression of mitochondrial uncoupling protein 1 (UCP1). The simultaneous treatment with β-adrenergic receptor agonists and Ang II attenuated UCP1 expression, triglyceride lipolysis, and cAMP levels, although cAMP response element-binding protein (CREB) phosphorylation was enhanced by Ang II mainly through the protein kinase C pathway. Despite reduced lipolysis, both coupled and uncoupled mitochondrial respiration was enhanced in Ang II-treated ciBAs. Instead, glycolysis and glucose uptake were robustly activated upon treatment with Ang II without a comprehensive transcriptional change in glucose metabolic genes. Elevated mitochondrial energy status induced by Ang II was likely associated with UCP1 repression. Our findings suggest that the Ang II/AGTR1 axis participates in mitochondrial thermogenic functions via glycolysis.

E4BP4 in macrophages induces an anti-inflammatory phenotype that ameliorates the severity of colitis

Macrophages are versatile cells of the innate immune system that work by altering their pro- or anti-inflammatory features. Their dysregulation leads to inflammatory disorders such as inflammatory bowel disease. We show that macrophage-specific upregulation of the clock output gene and transcription factor E4BP4 reduces the severity of colitis in mice. RNA-sequencing and single-cell analyses of macrophages revealed that increased expression of E4BP4 leads to an overall increase in expression of anti-inflammatory genes including Il4ra with a concomitant reduction in pro-inflammatory gene expression. In contrast, knockout of E4BP4 in macrophages leads to increased proinflammatory gene expression and decreased expression of anti-inflammatory genes. ChIP-seq and ATAC-seq analyses further identified Il4ra as a target of E4BP4, which drives anti-inflammatory polarization in macrophages. Together, these results reveal a critical role for E4BP4 in regulating macrophage inflammatory phenotypes and resolving inflammatory bowel diseases.

Endogenous aldehyde-induced DNA-protein crosslinks are resolved by transcription-coupled repair

DNA-protein crosslinks (DPCs) induced by aldehydes interfere with replication and transcription. Hereditary deficiencies in DPC repair and aldehyde clearance processes cause progeria, including Ruijs-Aalfs syndrome (RJALS) and AMeD syndrome (AMeDS) in humans. Although the elimination of DPC during replication has been well established, how cells overcome DPC lesions in transcription remains elusive. Here we show that endogenous aldehyde-induced DPC roadblocks are efficiently resolved by transcription-coupled repair (TCR). We develop a high-throughput sequencing technique to measure the genome-wide distribution of DPCs (DPC-seq). Using proteomics and DPC-seq, we demonstrate that the conventional TCR complex as well as VCP/p97 and the proteasome are required for the removal of formaldehyde-induced DPCs. TFIIS-dependent cleavage of RNAPII transcripts protects against transcription obstacles. Finally, a mouse model lacking both aldehyde clearance and TCR confirms endogenous DPC accumulation in actively transcribed regions. Collectively, our data provide evidence that transcription-coupled DPC repair (TC-DPCR) as well as aldehyde clearance are crucial for protecting against metabolic genotoxin, thus explaining the molecular pathogenesis of AMeDS and other disorders associated with defects in TCR, such as Cockayne syndrome.

Molecular structure and function of mysterin/RNF213

Mysterin is a large intracellular protein harboring a RING finger ubiquitin ligase domain and is also referred to as RING finger protein 213 (RNF213). The author performed the first molecular cloning of the mysterin gene as the final step in genetic exploration of cerebrovascular moyamoya disease (MMD) and initiated the next round of exploration to understand its molecular and cellular functions. Although much remains unknown, accumulating findings suggest that mysterin functions in cells by targeting massive intracellular structures, such as lipid droplets (LDs) and various invasive pathogens. In the latter case, mysterin appears to directly surround and ubiquitylate the surface of pathogens and stimulate cell-autonomous antimicrobial reactions, such as xenophagy and inflammatory response. To date, multiple mutations causing MMD have been identified within and near the RING finger domain of mysterin; however, their functional relevance remains largely unknown. Besides the RING finger, mysterin harbors a dynein-like ATPase core and an RZ finger, another ubiquitin ligase domain unique to mysterin, while functional exploration of these domains has also just commenced. In this review, the author attempts to summarize the core findings regarding the molecular structure and function of the mysterin protein, with an emphasis on the perspective of MMD research.

In the face and neck, keloid scar distribution is related to skin thickness and stiffness changes associated with movement

Keloid scars tend to occur in high-tension sites due to mechanical stimuli that are involved in their development. To date, a detailed analysis of keloid distribution focused specifically on facial and neck areas has not been reported, and limited literature exists as to the related mechanical factors. To rectify this deficiency of knowledge, we first quantified the facial and neck keloid distribution observed clinically in 113 patients. Subsequently, we performed a rigorous investigation into the mechanical factors and their associated changes at these anatomic sites in healthy volunteers without a history of pathologic scarring. The association between keloid-predilection sites and sebaceous gland-dense and acne-prone sites was also examined. To assess skin stretch, thickness and stiffness, VECTRA, ultrasound and indentometer were utilised. Baseline skin stiffness and thickness were measured, as well as the magnitude of change in these values associated with facial expression and postural changes. Within the face and neck, keloids were most common near the mandibular angle (41.3%) and lateral submental (20.0%) regions. These areas of increased keloid incidence were not associated with areas more dense in sebaceous glands, nor linked consistently with acne-susceptible regions. Binomial logistic regression revealed that changes in skin stiffness and thickness related to postural changes significantly predicted keloid distribution. Skin stiffness and thickness changes related to prolonged mechanical forces (postural changes) are most pronounced at sites of high keloid predilection. This finding further elucidates the means by which skin stretch and tension are related to keloid development. As a more detailed analysis of mechanical forces on facial and neck skin, this study evaluates the nuances of multiple skin-mechanical properties, and their changes in a three-dimensional framework. Such factors may be critical to better understanding keloid progression and development in the face and neck.

TRAF6 signaling in T cells is crucial for the pathogenicity of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an incurable chronic autoimmune disease affecting the central nervous system (CNS). Although IL-17-producing helper T (Th17) cells are thought to be one of the exacerbating factors in MS, the underlying pathogenic mechanism is incompletely understood. TNF receptor-associated factor 6 (TRAF6) deficient T cells exhibited enhanced Th17 cell differentiation, however, the physiological relevance of TRAF6 in T cells remains unknown. Here, we induced experimental autoimmune encephalomyelitis (EAE) in T cell-specific TRAF6 deficient (TRAF6ΔT) mice to investigate the role of TRAF6 in T cells during the course of MS using an EAE model. Although Th17 cell differentiation was enhanced in TRAF6ΔT mice, mutant mice were resistant to EAE. In contrast, TRAF6 loss did not affect regulatory T-cell differentiation. Consistent with the severity of EAE, a small number of infiltrating T cells and a small area of demyelination were observed in the CNS of TRAF6ΔT mice. Moreover, myelin oligodendrocyte glycoprotein-induced IL-17 production in TRAF6-deficient T cells was significantly suppressed. We further confirmed lower levels of CD69 and granulocyte-macrophage colony-stimulating factor in Th17 cells of TRAF6ΔT mice than in wild-type mice. In contrast, the expression of IL-10 and cytotoxic T-lymphocyte-associated protein 4 in T cells was significantly elevated in the absence of TRAF6 because of enhanced T-cell receptor signaling. Collectively, TRAF6 signaling in T cells contributes to the pathogenesis of EAE by regulating the pathogenicity and autoantigen reactivity of Th17 cells.

STAP-2 facilitates insulin signaling through binding to CAP/c-Cbl and regulates adipocyte differentiation

Signal-transducing adaptor protein-2 (STAP-2) is an adaptor molecule involved in several cellular signaling cascades. Here, we attempted to identify novel STAP-2 interacting molecules, and identified c-Cbl associated protein (CAP) as a binding protein through the C-terminal proline-rich region of STAP-2. Expression of STAP-2 increased the interaction between CAP and c-Cbl, suggesting that STAP-2 bridges these proteins and enhances complex formation. CAP/c-Cbl complex is known to regulate GLUT4 translocation in insulin signaling. STAP-2 overexpressed human hepatocyte Hep3B cells showed enhanced GLUT4 translocation after insulin treatment. Elevated levels of Stap2 mRNA have been observed in 3T3-L1 cells and mouse embryonic fibroblasts (MEFs) during adipocyte differentiation. The differentiation of 3T3-L1 cells into adipocytes was highly promoted by retroviral overexpression of STAP-2. In contrast, STAP-2 knockout (KO) MEFs exhibited suppressed adipogenesis. The increase in body weight with high-fat diet feeding was significantly decreased in STAP-2 KO mice compared to WT animals. These data suggest that the expression of STAP-2 correlates with adipogenesis. Thus, STAP-2 is a novel regulatory molecule that controls insulin signal transduction by forming a c-Cbl/STAP-2/CAP ternary complex.

Circadian rhythm of intraocular pressure

Intraocular pressure (IOP) plays a crucial role in glaucoma development, involving the dynamics of aqueous humor (AH). AH flows in from the ciliary body and exits through the trabecular meshwork (TM). IOP follows a circadian rhythm synchronized with the suprachiasmatic nucleus (SCN), the circadian pacemaker. The SCN resets peripheral clocks through sympathetic nerves or adrenal glucocorticoids (GCs). IOP's circadian rhythm is governed by circadian time signals, sympathetic noradrenaline (NE), and GCs, rather than the local clock. The activity of Na+/K+-ATPase in non-pigmented epithelial cells in the ciliary body can influence the nocturnal increase in IOP by enhancing AH inflow. Conversely, NE, not GCs, can regulate the IOP rhythm by suppressing TM macrophage phagocytosis and AH outflow. The activation of the β1-adrenergic receptor (AR)-mediated EPAC-SHIP1 signal through the ablation of phosphatidylinositol triphosphate may govern phagocytic cup formation. These findings could offer insights for better glaucoma management, such as chronotherapy.

Machine learning-based gait analysis to predict clinical frailty scale in elderly patients with heart failure

Aims

Although frailty assessment is recommended for guiding treatment strategies and outcome prediction in elderly patients with heart failure (HF), most frailty scales are subjective, and the scores vary among raters. We sought to develop a machine learning-based automatic rating method/system/model of the clinical frailty scale (CFS) for patients with HF.

Methods and results

We prospectively examined 417 elderly (≥75 years) with symptomatic chronic HF patients from 7 centres between January 2019 and October 2023. The patients were divided into derivation (n = 194) and validation (n = 223) cohorts. We obtained body-tracking motion data using a deep learning-based pose estimation library, on a smartphone camera. Predicted CFS was calculated from 128 key features, including gait parameters, using the light gradient boosting machine (LightGBM) model. To evaluate the performance of this model, we calculated Cohen's weighted kappa (CWK) and intraclass correlation coefficient (ICC) between the predicted and actual CFSs. In the derivation and validation datasets, the LightGBM models showed excellent agreements between the actual and predicted CFSs [CWK 0.866, 95% confidence interval (CI) 0.807-0.911; ICC 0.866, 95% CI 0.827-0.898; CWK 0.812, 95% CI 0.752-0.868; ICC 0.813, 95% CI 0.761-0.854, respectively]. During a median follow-up period of 391 (inter-quartile range 273-617) days, the higher predicted CFS was independently associated with a higher risk of all-cause death (hazard ratio 1.60, 95% CI 1.02-2.50) after adjusting for significant prognostic covariates.

Conclusion

Machine learning-based algorithms of automatically CFS rating are feasible, and the predicted CFS is associated with the risk of all-cause death in elderly patients with HF.

Pharmacological HIF-1 activation upregulates extracellular vesicle production synergistically with adiponectin through transcriptional induction and protein stabilization of T-cadherin

Pharmacological activation of hypoxia-inducible factor 1 (HIF-1), a hypoxia-responsive transcription factor, has attracted increasing attention due to its efficacy not only in renal anemia but also in various disease models. Our study demonstrated that a HIF-1 activator enhanced extracellular vesicle (EV) production from cultured endothelial cells synergistically with adiponectin, an adipocyte-derived factor, through both transcriptional induction and posttranscriptional stabilization of an adiponectin binding partner, T-cadherin. Increased EV levels were observed in wild-type mice but not in T-cadherin null mice after consecutive administration of roxadustat. Adiponectin- and T-cadherin-dependent increased EV production may be involved in the pleiotropic effects of HIF-1 activators.

DDX5 enhances HIF-1 activity by promoting the interaction of HIF-1α with HIF-1β and recruiting the resulting heterodimer to its target gene loci

BACKGROUND INFORMATION

Cancer cells acquire malignant characteristics and therapy resistance by employing the hypoxia-inducible factor 1 (HIF-1)-dependent adaptive response to hypoxic microenvironment in solid tumors. Since the underlying molecular mechanisms remain unclear, difficulties are associated with establishing effective therapeutic strategies.

RESULTS

We herein identified DEAD-box helicase 5 (DDX5) as a novel activator of HIF-1 and found that it enhanced the heterodimer formation of HIF-1α and HIF-1β and facilitated the recruitment of the resulting HIF-1 to its recognition sequence, hypoxia-response element (HRE), leading to the expression of a subset of cancer-related genes under hypoxia.

CONCLUSIONS

This study reveals that the regulation of HIF-1 recruitment to HRE is an important regulatory step in the control of HIF-1 activity.

SIGNIFICANCE

The present study provides novel insights for the development of strategies to inhibit the HIF-1-dependent expression of cancer-related genes.

A newly identified compound activating UCP1 inhibits obesity and its related metabolic disorders

OBJECTIVE

Promoting thermogenesis in adipose tissue has been a promising strategy against obesity and related metabolic complications. We aimed to identify compounds that promote thermogenesis in adipocytes and to elucidate their functions and roles in metabolism.

METHODS

To identify compounds that directly promote thermogenesis from a structurally diverse set of 4800 compounds, we utilized a cell-based platform for high-throughput screening that induces uncoupling protein 1 (Ucp1) expression in adipocytes.

RESULTS

We identified one candidate compound that activates UCP1. Additional characterization of this compound revealed that it induced cellular thermogenesis in adipocytes with negligible cytotoxicity. In a subsequent diet-induced obesity model, mice treated with this compound exhibited a slower rate of weight gain, improved insulin sensitivity, and increased energy expenditure. Mechanistic studies have revealed that this compound increases mitochondrial biogenesis by elevating maximal respiration, which is partly mediated by the protein kinase A (PKA)-p38 mitogen-activated protein kinase (MAPK) signaling pathway. A further comprehensive genetic analysis of adipocytes treated with these compounds identified two novel UCP1-dependent thermogenic genes, potassium voltage-gated channel subfamily C member 2 (Kcnc2) and predicted gene 5627 (Gm5627).

CONCLUSIONS

The identified compound can serve as a potential therapeutic drug for the treatment of obesity and its related metabolic disorders. Furthermore, our newly clarified thermogenic genes play an important role in UCP1-dependent thermogenesis in adipocytes.

Astrocytic Extracellular Vesicles Regulated by Microglial Inflammatory Responses Improve Stroke Recovery

There are no effective treatments for post-stroke glial scar formation, which inhibits axonal outgrowth and functional recovery after stroke. We investigated whether astrocytic extracellular vesicles (AEVs) regulated by microglia modulate glial scars and improve stroke recovery. We found that peri-infarct glial scars comprised reactive astrocytes with proliferating C3d and decreased S100A10 expression in chronic stroke. In cultured astrocytes, microglia-conditioned media and treatment with P2Y1 receptor antagonists increased and reduced the area of S100A10- and C3d-expressing reactive astrocytes, respectively, by suppressing mitogen-activated protein kinase/nuclear factor-κβ (NF-κB)/tumor necrosis factor-α (TNF-α)/interleukin-1β signaling after oxygen-glucose deprivation. Intracerebral administrations of AEVs enriched miR-146a-5p, downregulated NF-κB, and suppressed TNF-α expressions, by transforming reactive astrocytes to those with S100A10 preponderance, causing functional recovery in rats subjected to middle cerebral artery occlusion. Modulating neuroinflammation in post-stroke glial scars could permit axonal outgrowth, thus providing a basis for stroke recovery with neuroprotective AEVs.

Combination of blockade of endothelin signalling and compensation of IGF1 expression protects the retina from degeneration

Retinitis pigmentosa (RP) and macular dystrophy (MD) cause severe retinal dysfunction, affecting 1 in 4000 people worldwide. This disease is currently assumed to be intractable, because effective therapeutic methods have not been established, regardless of genetic or sporadic traits. Here, we examined a RP mouse model in which the Prominin-1 (Prom1) gene was deficient and investigated the molecular events occurring at the outset of retinal dysfunction. We extracted the Prom1-deficient retina subjected to light exposure for a short time, conducted single-cell expression profiling, and compared the gene expression with and without stimuli. We identified the cells and genes whose expression levels change directly in response to light stimuli. Among the genes altered by light stimulation, Igf1 was decreased in rod photoreceptor cells and astrocytes under the light-stimulated condition. Consistently, the insulin-like growth factor (IGF) signal was weakened in light-stimulated photoreceptor cells. The recovery of Igf1 expression with the adeno-associated virus (AAV) prevented photoreceptor cell death, and its treatment in combination with the endothelin receptor antagonist led to the blockade of abnormal glial activation and the promotion of glycolysis, thereby resulting in the improvement of retinal functions, as assayed by electroretinography. We additionally demonstrated that the attenuation of mammalian/mechanistic target of rapamycin (mTOR), which mediates IGF signalling, leads to complications in maintaining retinal homeostasis. Together, we propose that combinatorial manipulation of distinct mechanisms is useful for the maintenance of the retinal condition.

Caveolin-1 forms a complex with P2X7 receptor and tunes P2X7-mediated ATP signaling in mouse bone marrow-derived macrophages

The ionotropic purinergic P2X7 receptor responds to extracellular ATP and can trigger proinflammatory immune signaling in macrophages. Caveolin-1 (Cav-1) is known to modulate functions of macrophages and innate immunity. However, it is unknown how Cav-1 modulates P2X7 receptor activity in macrophages. We herein examined P2X7 receptor activity and macrophage functions using bone marrow-derived macrophages (BMDMs) from wild-type (WT) and Cav-1 knockout (KO) mice. ATP (1 mM) application caused biphasic increase in cytosolic [Ca2+] and sustained decrease in cytosolic [K+]. A specific P2X7 receptor blocker, A-740003, inhibited the maintained cytosolic [Ca2+] increase and cytosolic [K+] decrease. Total internal reflection fluorescent imaging and proximity ligation assays revealed a novel molecular complex formation between P2X7 receptors and Cav-1 in WT BMDMs that were stimulated with lipopolysaccharides. This molecular coupling was increased by ATP application. Specifically, the ATP-induced Ca2+ influx and K+ efflux through P2X7 receptors were increased in Cav-1 KO BMDMs, even though the total and surface protein levels of P2X7 receptors in WT and Cav-1 KO BMDMs were unchanged. Cell-impermeable dye (TO-PRO3) uptake analysis revealed that macropore formation of P2X7 receptors was enhanced in Cav-1 KO BMDMs. Cav-1 KO BMDMs increased ATP-induced IL-1β secretion, reactive oxygen species production, Gasdermin D (GSDMD) cleavage, and lactate dehydrogenase release indicating pyroptosis. A-740003 completely prevented ATP-induced pyroptosis. In combination, these datasets show that Cav-1 has a negative effect on P2X7 receptor activity in BMDMs and that Cav-1 in macrophages may contribute to finely tuned immune responses by preventing excessive IL-1β secretion and pyroptosis.NEW & NOTEWORTHY In bone marrow-derived macrophages, Cav-1 suppresses the macropore formation of P2X7 receptors through their direct or indirect interactions, resulting in reduced membrane permeability of cations (Ca2+ and K+) and large cell-impermeable dye (TO-PRO3) induced by ATP. Cav-1 also inhibits ATP-induced IL-1β secretion, ROS production, GSDMD cleavage, and pyroptosis. Cav-1 contributes to the maintenance of proper immune responses by finely tuning IL-1β secretion and cell death in macrophages.

Transrectal ultrasound vector projectile imaging for time-resolved visualization of flow dynamics in the male urethra: A clinical pilot study

BACKGROUND

Quantitative and comprehensive visualization of urinary flow dynamics in the urethra is crucial for investigating patient-specific mechanisms of lower urinary tract symptoms (LUTS). Although some methods can evaluate the global properties of the urethra, it is critical to assess the local information, such as the location of the responsible lesion and its interactions with urinary flow in relation to LUTS. This approach is vital for enhancing personalized and focal treatments. However, there is a lack of such diagnostic tools that can directly observe how the urethral shape and motion impact urinary flow in the urethra.

PURPOSE

This study aimed to develop a novel transrectal ultrasound imaging modality based on the contrast-enhanced urodynamic vector projectile imaging (CE-UroVPI) framework and validate its clinical applicability for visualizing time-resolved flow dynamics in the urethra.

METHODS

A new CE-UroVPI system was developed using a research-purpose ultrasound platform and a custom transrectal linear probe, and an imaging protocol for acquiring urodynamic echo data in male patients was designed. Thirty-four male patients with LUTS participated in this study. CE-UroVPI was performed to acquire ultrasound echo signals from the participant's urethra and urinary flow at various voiding phases (initiation, maintenance, and terminal). The ultrasound datasets were processed with custom software to visualize urinary flow dynamics and urethra tissue deformation.

RESULTS

The transrectal CE-UroVPI system successfully visualized the time-resolved multidirectional urinary flow dynamics in the prostatic urethra during the initiation, maintenance, and terminal phases of voiding in 17 patients at a frame rate of 1250 fps. The maximum flow speed measured in this study was 2.5 m/s. In addition, when the urethra had an obstruction or an irregular partial deformation, the devised imaging modality visualized complex flow patterns, such as vortices and flow jets around the lesion.

CONCLUSIONS

Our study findings demonstrate that the transrectal CE-UroVPI system developed in this study can effectively image fluid-structural interactions in the urethra. This new diagnostic technology has the potential to facilitate quantitative and precise assessments of urethral voiding functions and aid in the improvement of focal and effective treatments for patients with LUTS.

GR-KLF15 pathway controls hepatic lipogenesis during fasting

During periods of fasting, the body undergoes a metabolic shift from carbohydrate utilization to the use of fats and ketones as an energy source, as well as the inhibition of de novo lipogenesis and the initiation of gluconeogenesis in the liver. The transcription factor sterol regulatory element-binding protein-1 (SREBP-1), which plays a critical role in the regulation of lipogenesis, is suppressed during fasting, resulting in the suppression of hepatic lipogenesis. We previously demonstrated that the interaction of fasting-induced Kruppel-like factor 15 (KLF15) with liver X receptor serves as the essential mechanism for the nutritional regulation of SREBP-1 expression. However, the underlying mechanisms of KLF15 induction during fasting remain unclear. In this study, we show that the glucocorticoid receptor (GR) regulates the hepatic expression of KLF15 and, subsequently, lipogenesis through the KLF15-SREBP-1 pathway during fasting. KLF15 is necessary for the suppression of SREBP-1 by GR, as demonstrated through experiments using KLF15 knockout mice. Additionally, we show that GR is involved in the fasting response, with heightened binding to the KLF15 enhancer. It has been widely known that the hypothalamic-pituitary-adrenal (HPA) axis regulates the secretion of glucocorticoids and plays a significant role in the metabolic response to undernutrition. These findings demonstrate the importance of the HPA-axis-regulated GR-KLF15 pathway in the regulation of lipid metabolism in the liver during fasting.

Infectious virus shedding duration reflects secretory IgA antibody response latency after SARS-CoV-2 infection

Infectious virus shedding from individuals infected with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is used to estimate human-to-human transmission risk. Control of SARS-CoV-2 transmission requires identifying the immune correlates that protect infectious virus shedding. Mucosal immunity prevents infection by SARS-CoV-2, which replicates in the respiratory epithelium and spreads rapidly to other hosts. However, whether mucosal immunity prevents the shedding of the infectious virus in SARS-CoV-2-infected individuals is unknown. We examined the relationship between viral RNA shedding dynamics, duration of infectious virus shedding, and mucosal antibody responses during SARS-CoV-2 infection. Anti-spike secretory IgA antibodies (S-IgA) reduced viral RNA load and infectivity more than anti-spike IgG/IgA antibodies in infected nasopharyngeal samples. Compared with the IgG/IgA response, the anti-spike S-IgA post-infection responses affected the viral RNA shedding dynamics and predicted the duration of infectious virus shedding regardless of the immune history. These findings highlight the importance of anti-spike S-IgA responses in individuals infected with SARS-CoV-2 for preventing infectious virus shedding and SARS-CoV-2 transmission. Developing medical countermeasures to shorten S-IgA response time may help control human-to-human transmission of SARS-CoV-2 infection and prevent future respiratory virus pandemics.

Anaerobic threshold using sweat lactate sensor under hypoxia

We aimed to investigate the reliability and validity of sweat lactate threshold (sLT) measurement based on the real-time monitoring of the transition in sweat lactate levels (sLA) under hypoxic exercise. In this cross-sectional study, 20 healthy participants who underwent exercise tests using respiratory gas analysis under hypoxia (fraction of inspired oxygen [FiO2], 15.4 ± 0.8%) in addition to normoxia (FiO2, 20.9%) were included; we simultaneously monitored sLA transition using a wearable lactate sensor. The initial significant elevation in sLA over the baseline was defined as sLT. Under hypoxia, real-time dynamic changes in sLA were successfully visualized, including a rapid, continual rise until volitionary exhaustion and a progressive reduction in the recovery phase. High intra- and inter-evaluator reliability was demonstrated for sLT's repeat determinations (0.782 [0.607-0.898] and 0.933 [0.841-0.973]) as intraclass correlation coefficients [95% confidence interval]. sLT correlated with ventilatory threshold (VT) (r = 0.70, p < 0.01). A strong agreement was found in the Bland-Altman plot (mean difference/mean average time: - 15.5/550.8 s) under hypoxia. Our wearable device enabled continuous and real-time lactate assessment in sweat under hypoxic conditions in healthy participants with high reliability and validity, providing additional information to detect anaerobic thresholds in hypoxic conditions.

Transcription factor-mediated direct cellular reprogramming yields cell-type specific DNA methylation signature

Direct reprogramming, inducing the conversion of one type of somatic cell into another by the forced expression of defined transcription factors, is a technology with anticipated medical applications. However, due to the many unresolved aspects of the induction mechanisms, it is essential to thoroughly analyze the epigenomic state of the generated cells. Here, we performed comparative genome-wide DNA methylation analyses of mouse embryonic fibroblasts (MEFs) and cells composing organoids formed by intestinal stem cells (ISCs) or induced ISCs (iISCs) that were directly induced from MEFs. We found that the CpG methylation state was similar between cells forming ISC organoids and iISC organoids, while they differed widely from those in MEFs. Moreover, genomic regions that were differentially methylated between ISC organoid- and iISC organoid-forming cells did not significantly affect gene expression. These results demonstrate the accuracy and safety of iISC induction, leading to the medical applications of this technology.

Gastric inhibitory polypeptide receptor antagonism suppresses intramuscular adipose tissue accumulation and ameliorates sarcopenia

BACKGROUND

Intramuscular adipose tissue (IMAT) formation derived from muscle fibro-adipogenic progenitors (FAPs) has been recognized as a pathological feature of sarcopenia. This study aimed to explore whether genetic and pharmacological gastric inhibitory polypeptide (GIP) receptor antagonism suppresses IMAT accumulation and ameliorates sarcopenia in mice.

METHODS

Whole body composition, grip strength, skeletal muscle weight, tibialis anterior (TA) muscle fibre cross-sectional area (CSA) and TA muscle IMAT area were measured in young and aged male C57BL/6 strain GIP receptor (Gipr)-knockout (Gipr-/- ) and wild-type (Gipr+/+ ) mice. FAPs isolated from lower limb muscles of 12-week-old Gipr+/+ mice were cultured with GIP, and their differentiation into mature adipocytes was examined. Furthermore, TA muscle IMAT area and fibre CSA were measured in untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice after glycerol injection into the TA muscles.

RESULTS

Body composition analysis revealed that 104-week-old Gipr-/- mice had a greater proportion of lean tissue mass (73.7 ± 1.2% vs. 66.5 ± 2.7%, P < 0.05 vs. 104-week-old Gipr+/+ mice) and less adipose tissue mass (13.1 ± 1.3% vs. 19.4 ± 2.6%, P < 0.05 vs. 104-week-old Gipr+/+ mice). Eighty-four-week-old Gipr-/- mice exhibited increases in grip strength (P < 0.05), weights of TA (P < 0.05), soleus (P < 0.01), gastrocnemius (P < 0.05) and quadriceps femoris (P < 0.01) muscles, and average TA muscle fibre CSA (P < 0.05) along with a reduction in TA muscle IMAT area assessed by the number of perilipin-positive cells (P < 0.0001) compared with 84-week-old Gipr+/+ mice. Oil Red O staining analysis revealed 1.6- and 1.7-fold increased adipogenesis in muscle FAPs cultured with 10 and 100 nM of GIP (P < 0.01 and P < 0.001 vs. 0 nM of GIP, respectively). Furthermore, both untreated Gipr-/- mice and GIP receptor antagonist-treated Gipr+/+ mice for 14 days after glycerol injection into the TA muscles at 12 weeks of age showed reduced TA muscle IMAT area (1.39 ± 0.38% and 2.65 ± 0.36% vs. 6.54 ± 1.30%, P < 0.001 and P < 0.01 vs. untreated Gipr+/+ mice, respectively) and increased average TA muscle fibre CSA (P < 0.01 and P < 0.05 vs. untreated Gipr+/+ mice, respectively).

CONCLUSIONS

GIP promotes the differentiation of muscle FAPs into adipocytes and its receptor antagonism suppresses IMAT accumulation and promotes muscle regeneration. Pharmacological GIP receptor antagonism may serve as a novel therapeutic approach for sarcopenia.

Genetic engineering strategy for generating a stable dsRNA virus vector using a virus-like codon-modified transgene

IMPORTANCE

The stabilities of transgenes in RNA virus vectors differ between the genes of interest, but the molecular mechanisms determining genetic stability remain unknown. This study demonstrated that the stability of a transgene was affected by the nucleotide composition, and altering the codon usage of transgenes to resemble that of the viral genome significantly increased transgene stability in double-stranded RNA virus vectors. The virus-like codon modification strategy enabled generation of stable rotavirus and mammalian orthoreovirus vectors, which could be developed as machinery for gene delivery to the intestines and/or respiratory organs. This technology has further potential to be expanded to other RNA viruses.

Dynamics of depressive states among university students in Japan during the COVID-19 pandemic: an interrupted time series analysis

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic was reported to have increased depression among university students which was associated with impairments in their campus lives. This study examined changes in depressive states among Japanese university students during the COVID-19 pandemic.

METHODS

A secondary data analysis from a factorial randomized controlled trial involving smartphone-based cognitive-behavioral therapy was performed. Six cohorts (N = 1626) underwent an 8-week intervention during the spring or autumn of 2019-2021, with a 9-month follow-up. We evaluated participants' depressive states weekly using the Patient Health Questionnaire-9 (PHQ-9) during the intervention, with monthly evaluations thereafter. The follow-up periods included Japan's four states of emergency (SOEs) to control COVID-19. Hypothesizing that SOEs caused a sudden worsening of depressive states, Study 1 compared the cohorts' PHQ-9 scores, and Study 2 employed time series analysis with a mixed-effects model to estimate identified changes in PHQ-9 scores.

RESULTS

Although no changes in depressive states were observed in relation to the SOEs, Study 1 identified sudden increases in PHQ-9 scores at the 28-week evaluation point, which corresponded to the beginning of the new academic year for the three autumn cohorts. In contrast, the three spring cohorts did not exhibit similar changes. Study 2 showed that, for all three autumn cohorts (n = 522), the 0.60-point change was significant (95% CI 0.42-0.78; p < .001) at 28 weeks; that is, when their timeline was interrupted.

CONCLUSIONS

While the results do not indicate any notable impact of the SOEs, they highlight the influence of the new academic year on university students' mental health during COVID-19. Trial registration UMIN, CTR-000031307. Registered on February 14, 2018.

Decreased liver B vitamin-related enzymes as a metabolic hallmark of cancer cachexia

Cancer cachexia is a complex metabolic disorder accounting for ~20% of cancer-related deaths, yet its metabolic landscape remains unexplored. Here, we report a decrease in B vitamin-related liver enzymes as a hallmark of systemic metabolic changes occurring in cancer cachexia. Metabolomics of multiple mouse models highlights cachexia-associated reductions of niacin, vitamin B6, and a glycine-related subset of one-carbon (C1) metabolites in the liver. Integration of proteomics and metabolomics reveals that liver enzymes related to niacin, vitamin B6, and glycine-related C1 enzymes dependent on B vitamins decrease linearly with their associated metabolites, likely reflecting stoichiometric cofactor-enzyme interactions. The decrease of B vitamin-related enzymes is also found to depend on protein abundance and cofactor subtype. These metabolic/proteomic changes and decreased protein malonylation, another cachexia feature identified by protein post-translational modification analysis, are reflected in blood samples from mouse models and gastric cancer patients with cachexia, underscoring the clinical relevance of our findings.

Noninvasive evaluation of donor and native pancreases following simultaneous pancreas-kidney transplantation using positron emission tomography/computed tomography

It is crucial to develop practical and noninvasive methods to assess the functional beta-cell mass in a donor pancreas, in which monitoring and precise evaluation is challenging. A patient with type 1 diabetes underwent noninvasive imaging following simultaneous kidney-pancreas transplantation with positron emission tomography/computed tomography (PET/CT) using an exendin-based probe, [18 F]FB(ePEG12)12-exendin-4. Following transplantation, PET imaging with [18 F]FB(ePEG12)12-exendin-4 revealed simultaneous and distinct accumulations in the donor and native pancreases. The pancreases were outlined at a reasonable distance from the surrounding organs using [18 F]FB(ePEG12)12-exendin-4 whole-body maximum intensity projection and axial PET images. At 1 and 2 h after [18 F]FB(ePEG12)12-exendin-4 administration, the mean standardized uptake values were 2.96 and 3.08, respectively, in the donor pancreas and 1.97 and 2.25, respectively, in the native pancreas. [18 F]FB(ePEG12)12-exendin-4 positron emission tomography imaging allowed repeatable and quantitative assessment of beta-cell mass following simultaneous kidney-pancreas transplantation.

Methyl vinyl ketone impairs spatial memory and activates hippocampal glial cells in mice

Memory is a fundamental brain function that can be affected by a variety of external factors including environmental pollutants. One of these pollutants is methyl vinyl ketone (MVK), a hazardous substance found in cigarettes, industrial wastes, and car exhaust. Humans can be exposed to MVK under many circumstances; however, it is unclear whether MVK affects higher-order brain functions such as memory. Here, we examined the memory performances of mice receiving systemic MVK administration. We found that 1 mg/kg of MVK impaired spatial memory. We also showed that 1 mg/kg MVK activated glial cells and altered glial functions in several subregions of the hippocampus, a brain region involved in learning and memory. These results suggest that MVK induces memory deficits and activates glial cells in hippocampal subregions.

One-carbon metabolizing enzyme ALDH1L1 influences mitochondrial metabolism through 5-aminoimidazole-4-carboxamide ribonucleotide accumulation and serine depletion, contributing to tumor suppression

Tumor cells generally require large amounts of nucleotides, and thus activate de novo purine synthesis (dnPS). In the dnPS reactions, 10-formyltetrahydorofolate (10-fTHF) supplied by one-carbon metabolism is utilized as a formyl group donor. We focused on aldehyde dehydrogenase 1 family member L1 (ALDH1L1), which metabolizes 10-fTHF to tetrahydrofolate and whose expression is often attenuated in hepatocellular carcinoma (HCC). We generated ALDH1L1-expressing HuH-7 cells to perform metabolome analysis and found that intracellular levels of serine were reduced and glycine was increased. In addition, 5-aminoimidazole-4-carboxamide ribonucleotide (ZMP), a dnPS intermediate, accumulated due to the consumption of 10-fTHF by ALDH1L1, which inhibited ZMP formylation. Importantly, ALDH1L1-expressing cells showed reduced ZMP sensitivity and higher mitochondrial activity. The suppression of mitochondrial serine catabolism by ALDH1L1 expression was speculated to be closely related to this phenotype. Gene set enrichment analysis utilizing The Cancer Genome Atlas data revealed that genes related to oxidative phosphorylation were enriched in HCC patients with high ALDH1L1 expression. Moreover, drug sensitivity data analysis demonstrated that HCC cell lines with low expression of ALDH1L1 were sensitive to ZMP and cordycepin, a structural analog of ZMP and AMP. Our study revealed that ZMP and AMP analogs might be effective in the pharmacotherapy of HCC patients with low expression of ALDH1L1.

Alpha 7 nicotinic acetylcholine receptors signaling boosts cell-cell interactions in macrophages effecting anti-inflammatory and organ protection

Activation of the cholinergic anti-inflammatory pathway (CAP) via vagus nerve stimulation has been shown to improve acute kidney injury in rodent models. While alpha 7 nicotinic acetylcholine receptor (α7nAChR) positive macrophages are thought to play a crucial role in this pathway, their in vivo significance has not been fully understood. In this study, we used macrophage-specific α7nAChR-deficient mice to confirm the direct activation of α7nAChRs in macrophages. Our findings indicate that the administration of GTS-21, an α7nAChR-specific agonist, protects injured kidneys in wild-type mice but not in macrophage-specific α7nAChR-deficient mice. To investigate the signal changes or cell reconstructions induced by α7nAChR activation in splenocytes, we conducted single-cell RNA-sequencing of the spleen. Ligand-receptor analysis revealed an increase in macrophage-macrophage interactions. Using macrophage-derived cell lines, we demonstrated that GTS-21 increases cell contact, and that the contact between macrophages receiving α7nAChR signals leads to a reduction in TNF-α. Our results suggest that α7nAChR signaling increases macrophage-macrophage interactions in the spleen and has a protective effect on the kidneys.

Inhibition of GPR120 signaling in intestine ameliorates insulin resistance and fatty liver under high-fat diet feeding

G-protein-coupled receptor (GPR) 120 is expressed in enteroendocrine cells secreting glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide/gastric inhibitory polypeptide (GIP), and cholecystokinin (CCK). Although GPR120 signaling in adipose tissue and macrophages has been reported to ameliorate obesity and insulin resistance on high long-chain triglyceride (LCT) diet, intestine-specific roles of GPR120 are unclear. To clarify the metabolic effect of GPR120 in intestine, we generated intestine-specific GPR120-knockout (GPR120^int-/-) mice. In comparison with floxed GPR120 (WT) mice, GPR120^int-/- mice exhibited reduced GIP secretion and CCK action without change of insulin, GLP-1, or peptide YY (PYY) secretion after single administration of LCT. Under a high-LCT diet, GPR120^int-/- mice showed mild reduction of body weight and substantial amelioration of insulin resistance and fatty liver. Moreover, liver and white adipose tissue (WAT) of GPR120^int-/- mice exhibited increased Akt phosphorylation and reduced gene expression of suppressor of cytokine signaling (SOCS) 3, which inhibits insulin signaling. In addition, gene expression of inflammatory cytokines in WAT and lipogenic molecules in liver were reduced in GPR120^int-/- mice. These findings suggest that inhibition of GPR120 signaling in intestine ameliorates insulin resistance and fatty liver under high-LCT diet feeding.

Inhibition of N-glycosylation by glucosamine hydrochloride inhibits TGF-β1-induced LOXL2 secretion

Kidney fibrosis is closely associated with the progression of chronic kidney disease (CKD). Furthermore, copper-containing secretory amine oxidases, such as lysyl oxidase (LOX) and LOX-like 1-4 (LOXL1-4), play pivotal roles in the regulation of extracellular components and facilitate fibrosis. In this study, we investigated the regulation of LOX enzymes in human tubular epithelial HK2 cells to help clarify the role of LOX enzymes in kidney fibrosis. Among 5 LOX enzymes, LOXL2 expression is abundantly expressed in HK2 cells. LOX enzymes inhibitor, β-aminopropionitrile, suppressed transforming growth factor-β1 (TGF-β1)-promoted epithelial-to-mesenchymal transition processes in HK2 cells, indicating that LOX enzymes are involved in TGF-β1-mediated fibrotic processes. Recent studies suggest that LOX enzymes are secreted into the extracellular spaces by exosomes and promote fibrotic processes. Similar to the previous reports, we observed that exosomes secreted from HK2 cells carry LOXL2 into the extracellular spaces. Furthermore, we determined that N-glycosylation on the asparagine residues plays a key role in LOXL2 secretion. Amino acid mutations in three asparagine residues, which can be glycosylated, suppressed the secretion of mutated LOXL2. Moreover, N-acetylglucosaminyltransferase 5, an enzyme used for the biosynthesis of β1,6N-acetylglucosamine-branched N-glycans, participated in LOXL2 secretion, and the N-glycosylation inhibitor, glucosamine hydrochloride (GS), inhibited TGF-β1-mediated LOXL2 secretion and fibrotic processes. Overall, TGF-β1 promotes LOXL2 secretion and may participate in kidney fibrosis. Our results provide novel insight into the antifibrotic properties of GS that contribute to the inhibition of CKD progression.

Impact of Borna Disease Virus Infection on the Transcriptome of Differentiated Neuronal Cells and Its Modulation by Antiviral Treatment

Borna disease virus (BoDV-1) is a highly neurotropic RNA virus that causes neurobehavioral disturbances such as abnormal social activities and memory impairment. Although impairments in the neural circuits caused by BoDV-1 infection induce these disturbances, the molecular basis remains unclear. Furthermore, it is unknown whether anti-BoDV-1 treatments can attenuate BoDV-1-mediated transcriptomic changes in neuronal cells. In this study, we investigated the effects of BoDV-1 infection on neuronal differentiation and the transcriptome of differentiated neuronal cells using persistently BoDV-1-infected cells. Although BoDV-1 infection did not have a detectable effect on intracellular neuronal differentiation processes, differentiated neuronal cells exhibited transcriptomic changes in differentiation-related genes. Some of these transcriptomic changes, such as the decrease in the expression of apoptosis-related genes, were recovered by anti-BoDV-1 treatment, while alterations in the expression of other genes remained after treatment. We further demonstrated that a decrease in cell viability induced by differentiation processes in BoDV-1-infected cells can be relieved with anti-BoDV-1 treatment. This study provides fundamental information regarding transcriptomic changes after BoDV-1 infection and the treatment in neuronal cells.

Increased flexibility of the SARS-CoV-2 RNA-binding site causes resistance to remdesivir

Mutations continue to accumulate within the SARS-CoV-2 genome, and the ongoing epidemic has shown no signs of ending. It is critical to predict problematic mutations that may arise in clinical environments and assess their properties in advance to quickly implement countermeasures against future variant infections. In this study, we identified mutations resistant to remdesivir, which is widely administered to SARS-CoV-2-infected patients, and discuss the cause of resistance. First, we simultaneously constructed eight recombinant viruses carrying the mutations detected in in vitro serial passages of SARS-CoV-2 in the presence of remdesivir. We confirmed that all the mutant viruses didn’t gain the virus production efficiency without remdesivir treatment. Time course analyses of cellular virus infections showed significantly higher infectious titers and infection rates in mutant viruses than wild type virus under treatment with remdesivir. Next, we developed a mathematical model in consideration of the changing dynamic of cells infected with mutant viruses with distinct propagation properties and defined that mutations detected in in vitro passages canceled the antiviral activities of remdesivir without raising virus production capacity. Finally, molecular dynamics simulations of the NSP12 protein of SARS-CoV-2 revealed that the molecular vibration around the RNA-binding site was increased by the introduction of mutations on NSP12. Taken together, we identified multiple mutations that affected the flexibility of the RNA binding site and decreased the antiviral activity of remdesivir. Our new insights will contribute to developing further antiviral measures against SARS-CoV-2 infection.

Protonation states of Asp residues in the human Nudix hydrolase MTH1 contribute to its broad substrate recognition

Human MutT homolog 1 (MTH1), also known as Nudix-type motif 1 (NUDT1), hydrolyzes 8-oxo-dGTP and 2-oxo-dATP with broad substrate recognition and has attracted attention in anticancer therapeutics. Previous studies on MTH1 have proposed that the exchange of the protonation state between Asp119 and Asp120 is essential for the broad substrate recognition of MTH1. To understand the relationship between protonation states and substrate binding, we determined the crystal structures of MTH1 at pH 7.7-9.7. With increasing pH, MTH1 gradually loses its substrate-binding ability, indicating that Asp119 is deprotonated at pH 8.0-9.1 in 8-oxo-dGTP recognition and Asp120 is deprotonated at pH 8.6-9.7 in 2-oxo-dATP recognition. These results confirm that MTH1 recognizes 8-oxo-dGTP and 2-oxo-dATP by exchanging the protonation state between Asp119 and Asp120 with higher pK_a .

Indoleamine 2, 3-dioxygenase is responsible for low stress tolerance after intracerebral hemorrhage

In the chronic phase after intracerebral hemorrhage (ICH), the aftereffect-associated lowering of motivation burdens many patients; however, the pathogenic mechanism is unclear. Here, we revealed for the first time that indoleamine 2, 3-dioxygenase (IDO) expression and enzyme activity are increased in the collagenase-induced murine ICH model. IDO is a rate-limiting enzyme situated at the beginning of the kynurenine pathway and converts tryptophan, a source of serotonin (5-hydroxytryptamine; 5-HT), to kynurenine. In this study, we showed that IDO is localized in 5-HTergic neurons. After ICH, the synaptosomal 5-HT level decreased, but this effect was neutralized by subcutaneous injections of 1-methyl tryptophan (MT), a specific IDO inhibitor. These results suggest that ICH-induced IDO weakens the activity of 5-HTergic neurons. Accordingly, we next investigated whether the IDO increase contributes to the depression-like behaviors of ICH mice. The immobility times of tail suspension and forced swimming tests were significantly prolonged after ICH but shortened by the administration of 1-MT. In conclusion, the increased IDO after ICH was found to decrease 5-HT levels and subsequently reduce stress tolerance. These findings indicate that IDO is a novel therapeutic target for the ICH aftereffect-associated lowering of motivation.

Components of smartphone cognitive-behavioural therapy for subthreshold depression among 1093 university students: a factorial trial

BACKGROUND

Internet-based cognitive-behavioural therapy (iCBT) is effective for subthreshold depression. However, which skills provided in iCBT packages are more effective than others is unclear. Such knowledge can inform construction of more effective and efficient iCBT programmes.

OBJECTIVE

To examine the efficacy of five components of iCBT for subthreshold depression.

METHODS

We conducted an factorial trial using a smartphone app, randomly allocating presence or absence of five iCBT skills including self-monitoring, behavioural activation (BA), cognitive restructuring (CR), assertiveness training (AT) and problem-solving. Participants were university students with subthreshold depression. The primary outcome was the change on the Patient Health Questionnaire-9 (PHQ-9) from baseline to week 8. Secondary outcomes included changes in CBT skills.

FINDINGS

We randomised a total of 1093 participants. In all groups, participants had a significant PHQ-9 reduction from baseline to week 8. Depression reduction was not significantly different between presence or absence of any component, with corresponding standardised mean differences (negative values indicate specific efficacy in favour of the component) ranging between -0.04 (95% CI -0.16 to 0.08) for BA and 0.06 (95% CI -0.06 to 0.18) for AT. Specific CBT skill improvements were noted for CR and AT but not for the others.

CONCLUSIONS

There was significant reduction in depression for all participants regardless of the presence and absence of the examined iCBT components.

CLINICAL IMPLICATION

We cannot yet make evidence-based recommendations for specific iCBT components. We suggest that future iCBT optimisation research should scrutinise the amount and structure of components to examine.

TRIAL REGISTRATION NUMBER

UMINCTR-000031307.

Senescence-accelerated mice prone 8 (SAMP8) in male as a spontaneous osteoarthritis model

BACKGROUND

Animal models of spontaneous osteoarthritis (OA) are sparse and not well characterized. The purpose of the present study is to examine OA-related changes and mechanisms in senescence-accelerated mouse prone 8 (SAMP8) that displays a phenotype of accelerated aging.  METHODS: Knees of male SAMP8 and SAM-resistant 1 (SAMR1) mice as control from 6 to 33 weeks of age were evaluated by histological grading systems for joint tissues (cartilage, meniscus, synovium, and subchondral bone), and µCT analysis. Gene expression patterns in articular cartilage were analyzed by real-time PCR. Immunohistochemistry was performed for OA-related factors, senescence markers, and apoptosis.

RESULTS

Starting at 14 weeks of age, SAMP8 exhibited mild OA-like changes such as proteoglycan loss and cartilage fibrillation. From 18 to 33 weeks of age, SAMP8 progressed to partial or full-thickness defects with exposure of subchondral bone on the medial tibia and exhibited synovitis. Histological scoring indicated significantly more severe OA in SAMP8 compared with SAMR1 from 14 weeks [median (interquartile range): SAMR1: 0.89 (0.56-1.81) vs SAMP8: 1.78 (1.35-4.62)] to 33 weeks of age [SAMR1: 1.67 (1.61-1.04) vs SAMP8: 13.03 (12.26-13.57)]. Subchondral bone sclerosis in the medial tibia, bone mineral density (BMD) loss of femoral metaphysis, and meniscus degeneration occurred much earlier than the onset of cartilage degeneration in SAMP8 at 14 weeks of age.

CONCLUSIONS

SAMP8 are a spontaneous OA model that is useful for investigating the pathogenesis of primary OA and evaluating therapeutic interventions.

Artificial intelligence-derived gut microbiome as a predictive biomarker for therapeutic response to immunotherapy in lung cancer: protocol for a multicentre, prospective, observational study

INTRODUCTION

Immunotherapy is the fourth leading therapy for lung cancer following surgery, chemotherapy and radiotherapy. Recently, several studies have reported about the potential association between the gut microbiome and therapeutic response to immunotherapy. Nevertheless, the specific composition of the gut microbiome or combination of gut microbes that truly predict the efficacy of immunotherapy is not definitive.

METHODS AND ANALYSIS

The present multicentre, prospective, observational study aims to discover the specific composition of the gut microbiome or combination of gut microbes predicting the therapeutic response to immunotherapy in lung cancer using artificial intelligence. The main inclusion criteria are as follows: (1) pathologically or cytologically confirmed metastatic or postoperative recurrent lung cancer including non-small cell lung cancer and small cell lung cancer; (2) age≥20 years at the time of informed consent; (3) planned treatment with immunotherapy including combination therapy and monotherapy, as the first-line immunotherapy; and (4) ability to provide faecal samples. In total, 400 patients will be enrolled prospectively. Enrolment will begin in 2021, and the final analyses will be completed by 2024.

ETHICS AND DISSEMINATION

The study protocol was approved by the institutional review board of each participating centre in 2021 (Kyushu Cancer Center, IRB approved No. 2021-13, 8 June 2021 and Kyushu Medical Center, IRB approved No. 21-076, 31 August 2021). Study results will be disseminated through peer-reviewed journals and national and international conferences.

TRIAL REGISTRATION NUMBER

UMIN000046428.

siRNA Seed Region Is Divided into Two Functionally Different Domains in RNA Interference in Response to 2'-OMe Modifications

In RNA interference (RNAi), small interfering RNA (siRNA) functions to suppress the expression of its target mRNA with perfect sequence complementarity. In a mechanism different from above, siRNA also suppresses unintended mRNAs with partial sequence complementarities, mainly to the siRNA seed region (nucleotides 2-8). This mechanism is largely utilized by microRNAs (miRNAs) and results in siRNA-mediated off-target effects. Thus, the siRNA seed region is considered to be involved in both RNAi and off-target effects. In this study, we revealed that the impact of 2'-O-methyl (2'-OMe) modification is different according to the nucleotide positions. The 2'-OMe modifications of nucleotides 2-5 inhibited off-target effects without affecting on-target RNAi activities. In contrast, 2'-OMe modifications of nucleotides 6-8 increased both RNAi and off-target activities. The computational simulation revealed that the structural change induced by 2'-OMe modifications interrupts base pairing between siRNA and target/off-target mRNAs at nucleotides 2-5 but enhances at nucleotides 6-8. Thus, our results suggest that siRNA seed region consists of two functionally different domains in response to 2'-OMe modifications: nucleotides 2-5 are essential for avoiding off-target effects, and nucleotides 6-8 are involved in the enhancement of both RNAi and off-target activities.

ACC1-expressing pathogenic T helper 2 cell populations facilitate lung and skin inflammation in mice

T cells possess distinguishing effector functions and drive inflammatory disorders. We have previously identified IL-5-producing Th2 cells as the pathogenic population predominantly involved in the pathology of allergic inflammation. However, the cell-intrinsic signaling pathways that control the pathogenic Th2 cell function are still unclear. We herein report the high expression of acetyl-CoA carboxylase 1 (ACC1) in the pathogenic CD4+ T cell population in the lung and skin. The genetic deletion of CD4+ T cell-intrinsic ACC1 dampened eosinophilic and basophilic inflammation in the lung and skin by constraining IL-5 or IL-3 production. Mechanistically, ACC1-dependent fatty acid biosynthesis induces the pathogenic cytokine production of CD4+ T cells via metabolic reprogramming and the availability of acetyl-CoA for epigenetic regulation. We thus identified a distinct phenotype of the pathogenic T cell population in the lung and skin, and ACC1 was shown to be an essential regulator controlling the pathogenic function of these populations to promote type 2 inflammation.

Development of accurate temperature regulation culture system with metallic culture vessel demonstrates different thermal cytotoxicity in cancer and normal cells

Hyperthermia has been studied as a noninvasive cancer treatment. Cancer cells show stronger thermal cytotoxicity than normal cells, which is exploited in hyperthermia. However, the absence of methods evaluating the thermal cytotoxicity in cells prevents the development of hyperthermia. To investigate the thermal cytotoxicity, culture temperature should be regulated. We, thus, developed a culture system regulating culture temperature immediately and accurately by employing metallic culture vessels. Michigan Cancer Foundation-7 cells and normal human dermal fibroblasts were used for models of cancer and normal cells. The findings showed cancer cells showed stronger thermal cytotoxicity than normal cells, which is quantitatively different from previous reports. This difference might be due to regulated culture temperature. The thermal stimulus condition (43 °C/30 min) was, further, focused for assays. The mRNA expression involving apoptosis changed dramatically in cancer cells, indicating the strong apoptotic trend. In contrast, the mRNA expression of heat shock protein (HSP) of normal cells upon the thermal stimulus was stronger than cancer cells. Furthermore, exclusively in normal cells, HSP localization to nucleus was confirmed. These movement of HSP confer thermotolerance to cells, which is consistent with the different thermal cytotoxicity between cancer and normal cells. In summary, our developed system can be used to develop hyperthermia treatment.

Incomplete antiviral treatment may induce longer durations of viral shedding during SARS-CoV-2 infection

The duration of viral shedding is determined by a balance between de novo infection and removal of infected cells. That is, if infection is completely blocked with antiviral drugs (100% inhibition), the duration of viral shedding is minimal and is determined by the length of virus production. However, some mathematical models predict that if infected individuals are treated with antiviral drugs with efficacy below 100%, viral shedding may last longer than without treatment because further de novo infections are driven by entry of the virus into partially protected, uninfected cells at a slower rate. Using a simple mathematical model, we quantified SARS-CoV-2 infection dynamics in non-human primates and characterized the kinetics of viral shedding. We counterintuitively found that treatments initiated early, such as 0.5 d after virus inoculation, with intermediate to relatively high efficacy (30-70% inhibition of virus replication) yield a prolonged duration of viral shedding (by about 6.0 d) compared with no treatment.

A novel RFX6 heterozygous mutation (p.R652X) in maturity-onset diabetes mellitus: A case report

Heterozygous RFX6 mutation has emerged as a potential cause of maturity-onset diabetes mellitus of the young (MODY). A 16-year-old female was diagnosed with diabetes by her family doctor and was referred to our institution for genetic examination. Genetic testing revealed a novel RFX6 heterozygous mutation (NM_173560: exon17: c.1954C>T: p.R652X) in the patient and in her mother and brother. She had no islet-specific autoantibodies and showed a reduced meal-induced response of insulin, glucose-dependent insulinotropic polypeptide, and glucagon-like peptide-1, which is consistent with the phenotype of MODY due to heterozygous RFX6 mutation. In conclusion, we report a case of MODY due to a novel heterozygous mutation, p.R652X.

Revisiting the guidelines for ending isolation for COVID-19 patients

Since the start of the COVID-19 pandemic, two mainstream guidelines for defining when to end the isolation of SARS-CoV-2-infected individuals have been in use: the one-size-fits-all approach (i.e. patients are isolated for a fixed number of days) and the personalized approach (i.e. based on repeated testing of isolated patients). We use a mathematical framework to model within-host viral dynamics and test different criteria for ending isolation. By considering a fixed time of 10 days since symptom onset as the criterion for ending isolation, we estimated that the risk of releasing an individual who is still infectious is low (0-6.6%). However, this policy entails lengthy unnecessary isolations (4.8-8.3 days). In contrast, by using a personalized strategy, similar low risks can be reached with shorter prolonged isolations. The obtained findings provide a scientific rationale for policies on ending the isolation of SARS-CoV-2-infected individuals.

Identification of a novel endogenous long non-coding RNA that inhibits selenoprotein P translation

Selenoprotein P (SELENOP) is a major plasma selenoprotein that contains 10 Sec residues, which is encoded by the UGA stop codon. The mRNA for SELENOP has the unique property of containing two Sec insertion sequence (SECIS) elements, which is located in the 3' untranslated region (3'UTR). Here, we coincidentally identified a novel gene, CCDC152, by sequence analysis. This gene was located in the antisense region of the SELENOP gene, including the 3'UTR region in the genome. We demonstrated that this novel gene functioned as a long non-coding RNA (lncRNA) that decreased SELENOP protein levels via translational rather than transcriptional, regulation. We found that the CCDC152 RNA interacted specifically and directly with the SELENOP mRNA and inhibited its binding to the SECIS-binding protein 2, resulting in the decrease of ribosome binding. We termed this novel gene product lncRNA inhibitor of SELENOP translation (L-IST). Finally, we found that epigallocatechin gallate upregulated L-IST in vitro and in vivo, to suppress SELENOP protein levels. Here, we provide a new regulatory mechanism of SELENOP translation by an endogenous long antisense ncRNA.

Detection of significant antiviral drug effects on COVID-19 with reasonable sample sizes in randomized controlled trials: A modeling study

BACKGROUND

Development of an effective antiviral drug for Coronavirus Disease 2019 (COVID-19) is a global health priority. Although several candidate drugs have been identified through in vitro and in vivo models, consistent and compelling evidence from clinical studies is limited. The lack of evidence from clinical trials may stem in part from the imperfect design of the trials. We investigated how clinical trials for antivirals need to be designed, especially focusing on the sample size in randomized controlled trials.

METHODS AND FINDINGS

A modeling study was conducted to help understand the reasons behind inconsistent clinical trial findings and to design better clinical trials. We first analyzed longitudinal viral load data for Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) without antiviral treatment by use of a within-host virus dynamics model. The fitted viral load was categorized into 3 different groups by a clustering approach. Comparison of the estimated parameters showed that the 3 distinct groups were characterized by different virus decay rates (p-value < 0.001). The mean decay rates were 1.17 d-1 (95% CI: 1.06 to 1.27 d-1), 0.777 d-1 (0.716 to 0.838 d-1), and 0.450 d-1 (0.378 to 0.522 d-1) for the 3 groups, respectively. Such heterogeneity in virus dynamics could be a confounding variable if it is associated with treatment allocation in compassionate use programs (i.e., observational studies). Subsequently, we mimicked randomized controlled trials of antivirals by simulation. An antiviral effect causing a 95% to 99% reduction in viral replication was added to the model. To be realistic, we assumed that randomization and treatment are initiated with some time lag after symptom onset. Using the duration of virus shedding as an outcome, the sample size to detect a statistically significant mean difference between the treatment and placebo groups (1:1 allocation) was 13,603 and 11,670 (when the antiviral effect was 95% and 99%, respectively) per group if all patients are enrolled regardless of timing of randomization. The sample size was reduced to 584 and 458 (when the antiviral effect was 95% and 99%, respectively) if only patients who are treated within 1 day of symptom onset are enrolled. We confirmed the sample size was similarly reduced when using cumulative viral load in log scale as an outcome. We used a conventional virus dynamics model, which may not fully reflect the detailed mechanisms of viral dynamics of SARS-CoV-2. The model needs to be calibrated in terms of both parameter settings and model structure, which would yield more reliable sample size calculation.

CONCLUSIONS

In this study, we found that estimated association in observational studies can be biased due to large heterogeneity in viral dynamics among infected individuals, and statistically significant effect in randomized controlled trials may be difficult to be detected due to small sample size. The sample size can be dramatically reduced by recruiting patients immediately after developing symptoms. We believe this is the first study investigated the study design of clinical trials for antiviral treatment using the viral dynamics model.