Muscle Atrophy and mRNA-miRNA Network Analysis of Vascular Endothelial Growth Factor (VEGF) in a Mouse Model of Denervation-Induced Disuse.

BACKGROUND: Skeletal muscle atrophy is frequently caused by the disuse of muscles. It impacts quality of life, especially in aging populations and those with chronic diseases. Understanding the molecular mechanisms underlying muscle atrophy is crucial for developing effective therapies. OBJECTIVE: To investigate the roles of vascular endothelial growth factor (VEGF) and various microRNAs (miRNAs) in muscle atrophy using a mouse model of denervation (DEN)-induced disuse, and to elucidate their interactions and regulatory functions through comprehensive network analysis. METHODS: The right sciatic nerve of C57BL/6J mice (n=6) was excised to simulate DEN, with the left serving as a sham surgery control (Sham). Following a two-week period, wet muscle weight was measured. Total RNA was extracted from the tibialis anterior muscle for microarray analysis. Significant expression changes were analyzed via Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and miRNet for miRNAs. RESULTS: Denervated limbs showed a significant reduction in muscle weight. Over 1,000 genes displayed increased expression, while 527 showed reductions to less than half of control levels. VEGF, along with specific miRNAs such as miR-106a-5p, miR-mir20a-5p, mir93-5p and mir17-5p, occupied central regulatory nodes within the gene network. Functional analysis revealed that these molecules are involved in key biological processes including regulation of cell migration, vasculature development, and regulation of endothelial cell proliferation. The increased miRNAs were subjected to further network analysis that revealed significant regulatory interactions with target mRNAs. CONCLUSION: VEGF and miRNAs play crucial roles in the progression of skeletal muscle atrophy, offering potential targets for therapeutic interventions aimed at reducing atrophy and enhancing muscle regeneration.

Spatiotemporally distinct roles of cyclooxygenase-1 and cyclooxygenase-2 at fetomaternal interface in mice.

Embryo implantation is crucial for ensuring a successful pregnancy outcome and subsequent child health. The intrauterine environment during the peri-implantation period shows drastic changes in gene expression and cellular metabolism in response to hormonal stimuli and reciprocal communication with embryos. Here, we performed spatial transcriptomic analysis to elucidate the mechanisms underlying embryo implantation. Transcriptome data revealed that lipid metabolism pathways, especially arachidonic acid-related (AA-related) ones, were enriched in the embryo-receptive luminal epithelia. Cyclooxygenases (COXs), rate-limiting enzymes involved in prostaglandin production by AA, were spatiotemporally regulated in the vicinity of embryos during implantation, but the role of each COX isozyme in the uterus for successful pregnancy was unclear. We established uterine-specific COX2-knockout (uKO) and COX1/uterine COX2-double-KO (COX1/COX2-DKO) mice. COX2 uKO caused deferred implantation with failed trophoblast invasion, resulting in subfertility with reduced pregnancy rates and litter sizes. COX1/COX2 DKO induced complete infertility, owing to abrogated embryo attachment. These results demonstrate that both isozymes have distinct roles during embryo implantation. Spatial transcriptome and lipidome analyses revealed unique profiles of prostaglandin synthesis by each COX isozyme and spatiotemporal expression patterns of downstream receptors throughout the endometrium. Our findings reveal previously unappreciated roles of COXs at the fetomaternal interface to establish early pregnancy.

Dose-dependent association between estimated glomerular filtration rate and the subsequent risk of depression: An analysis of a nationwide epidemiological dataset.

BACKGROUND: Although the risk of depression is well-known in the patients with kidney dysfunction, especially at the late stages, little is known about the exact point at which the decline in estimated glomerular filtration rate (eGFR) begins to significantly increase the risk of depression. In the present study, we analysed a nationwide epidemiological dataset to investigate the dose-dependent association between baseline eGFR and a future risk of developing depression in a general population. METHODS: We retrospectively analysed 1,518,885 individuals (male: 46.3%) without a history of depression identified between April 2014 and November 2022 within a nationwide epidemiological database, provided by DeSC Healthcare (Tokyo, Japan). We investigated the association of eGFR with the incidence of depression using Cox regression analyses and also conducted cubic spline analysis to investigate the dose-dependent association between eGFR and depression. RESULTS: In the mean follow-up of 1218 ± 693 days, 45,878 cases (3.0% for total participants, 2.6% for men and 3.3% for women) of depression were recorded. The risk of depression increased with the eGFR decline as well as the presence of proteinuria. Multivariable Cox regression analysis showed the hazard ratio (95% CI) of depression in each kidney function category (eGFR ≥90, 60-89, 45-59, 30-44, 15-29, and < 15 mL/min/1.73 m2) was 1.14 (1.11-1.17), 1 (reference), 1.11 (1.08-1.14), 1.51 (1.43-1.59), 1.77 (1.57-1.99) and 1.77 (1.26-2.50), respectively. In the cubic spline analysis, the risk of depression continued to increase monotonically as the eGFR declined when the eGFR fell below approximately 65 mL/min/1.73 m2. CONCLUSIONS: Our analysis using a large-scale epidemiological dataset presented the dose-dependent association between eGFR decline and the risk of depression, which highlights the importance of incorporating mental health assessments into the routine care of patients with kidney dysfunction, regardless of the stage of their disease.

Association of Multiple Nonhypertrophic Cardiomyopathy-Related Genetic Variants and Outcomes in Patients With Hypertrophic Cardiomyopathy.

BACKGROUND: Approximately 10% of hypertrophic cardiomyopathy (HCM) patients have left ventricular systolic dysfunction (end-stage HCM) leading to severe heart-failure; however, risk stratification to identify patients at risk of progressing to end-stage HCM remains insufficient. OBJECTIVES: In this study, the authors sought to elucidate whether the coexistence of other cardiovascular disease (CVD)-related variants is associated with progression to end-stage HCM in patients with HCM harboring pathogenic or likely pathogenic (P/LP) sarcomeric variants. METHODS: The authors performed genetic analysis of 83 CVD-related genes in HCM patients from a Japanese multicenter cohort. P/LP variants in 8 major sarcomeric genes (MYBPC3, MYH7, TNNT2, TNNI3, TPM1, MYL2, MYL3, and ACTC1) definitive for HCM were defined as "sarcomeric variants." In addition, P/LP variants associated with other CVDs, such as dilated cardiomyopathy and arrhythmogenic cardiomyopathy, were referred to as "other CVD-related variants." RESULTS: Among 394 HCM patients, 139 carried P/LP sarcomeric variants: 11 (7.9%) carried other CVD-related variants, 6 (4.3%) multiple sarcomeric variants, and 122 (87.8%) single sarcomeric variants. In a multivariable Cox regression analysis, presence of multiple sarcomeric variants (adjusted HR [aHR]: 3.35 [95% CI: 1.25-8.95]; P = 0.016) and coexistence of other CVD-related variants (aHR: 2.80 [95% CI: 1.16-6.78]; P = 0.022) were independently associated with progression to end-stage HCM. Coexisting other CVD-related variants were also associated with heart failure events (aHR: 2.75 [95% CI: 1.27-5.94]; P = 0.010). CONCLUSIONS: Approximately 8% of sarcomeric HCM patients carried other CVD-related variants, which were associated with progression to end-stage HCM and heart failure events. Comprehensive surveillance of CVD-related variants within sarcomeric HCM patients contributes to risk stratification and understanding of mechanisms underlying end-stage HCM.

Lineage tracing using Wnt2b-2A-CreERT2 knock-in mice reveals the contributions of Wnt2b-expressing cells to novel subpopulations of mesothelial/epicardial cell lineages during mouse development.

Mesothelial and epicardial cells give rise to various types of mesenchymal cells via epithelial (mesothelial)-to-mesenchymal transition during development. However, the genes controlling the differentiation and diversification of mesothelial/epicardial cells remain unclear. Here, we examined Wnt2b expression in the embryonic mesothelium and epicardium and performed lineage tracing of Wnt2b-expressing cells by using novel Wnt2b-2A-CreERT2 knock-in and LacZ-reporter mice. Wnt2b was expressed in mesothelial cells covering visceral organs, but the expression was restricted in their subpopulations. Wnt2b-expressing cells labeled at embryonic day (E) 10.5 were distributed to the mesothelium and mesenchyme in the lungs, abdominal wall, stomach, and spleen in Wnt2b2A-CreERT2/+;R26RLacZ/+ mice at E13.0. Wnt2b was initially expressed in the proepicardial organ (PEO) at E9.5 and then in the epicardium after E10.0. Wnt2b-expressing PEO cells labeled at E9.5 differentiated into a small fraction of cardiac fibroblasts and preferentially localized at the left side of the postnatal heart. LacZ+ epicardium-derived cells labeled at E10.5 differentiated into a small fraction of fibroblasts and smooth muscle cells in the postnatal heart. Taken together, our results reveal novel subpopulations of PEO and mesothelial/epicardial cells that are distinguishable by Wnt2b expression and elucidate the unique contribution of Wnt2b-expressing PEO and epicardial cells to the postnatal heart.

A De Novo Missense MYLK Variant Leading to Nonsyndromic Thoracic Aortic Aneurysm and Dissection Identified by Segregation Analysis.

Nonsyndromic hereditary thoracic aortic aneurysm and dissection (TAAD) is an autosomal dominant disease; however, it is frequently difficult to identify the causative genes. We report in this study a 33-year-old Japanese male with TAAD (Stanford type A) that is complicated with severe aortic regurgitation. There was no family history of aortic diseases in the patient nor any specific clinical features suggestive of connective tissue diseases, such as Marfan syndrome. Genetic testing identified candidate causative variants in two different genes: MYLK (c.4819G > A, p.[Gly1607Ser]) and FBN1 (c.365G > A, p.[Arg122His]). Familial cosegregation analysis revealed that the novel de novo MYLK variant was present only in the proband, and the FBN1 variant was also found in his nonaffected mother, and thus the MYLK variant was classified as likely pathogenic. MYLK is a causative gene for nonsyndromic TAAD that requires careful management; however, the number of reports is limited. Accumulating data on the pathogenicity of rare variants by performing a comprehensive pedigree analysis would help establish better treatment strategies for life-threatening hereditary TAAD cases.

Management of an elderly patient with nonsyndromic TGFBR1-related aortopathy: A case report.

Key Clinical Message: Genetic variants associated with hereditary TAAD may contribute to nonsyndromic TAAD. We present the case of a 72-year-old man with nonsyndromic TAAD undergoing prophylactic surgery after a gene panel test revealed a pathogenic variant in TGFBR1, but the indication for genetic testing in such elderly-onset cases still warrants further discussion. Abstract: Hereditary thoracic aortic aneurysm and dissection (TAAD) is a serious clinical condition resulting in a fatal outcome. Recently, variants in causative genes for syndromic hereditary TAAD, such as Marfan syndrome and Loeys-Dietz syndrome (LDS), have been reported to predispose to the development of nonsyndromic TAAD; however, genetic testing for patients with elderly-onset nonsyndromic TAAD warrants further discussion. We present a 72-year-old nonsyndromic Japanese man with moderate-sized aortic annulus ectasia (AAE) with moderate aortic regurgitation and ascending to distal arch aortic dilatation (maximum diameter: 46 mm). He had been treated for hypertension and dyslipidemia for 7 years, and his eldest son had AAE at 33 years old and type A aortic dissection at 43 years old. Surgical repair was considered a treatment option because the patient potentially had a nonsyndromic hereditary aortic disease, and genetic panel testing for TAAD identified a pathogenic missense variant in TGFBR1 (c.934G > A, p.[Gly312Ser]), previously reported in patients with LDS type 1. He was diagnosed with nonsyndromic TGFBR1-related aortopathy and underwent prophylactic surgery using a modified Bentall operation and total arch replacement with open stent graft implantation. Genetic testing was useful in guiding the treatment strategy, but further analysis is warranted to establish the clinical value in the treatment plan for patients with elderly-onset nonsyndromic TAAD.

Body weight change associated kidney outcomes of sodium-glucose cotransporter new users.

AIM: To investigate the clinical significance of body weight changes on kidney outcomes among individuals with diabetes using sodium-glucose cotransporter-2 (SGLT2) inhibitors. MATERIALS AND METHODS: This is a retrospective cohort study using a nationwide epidemiological database, and we conducted an analysis involving 11 569 individuals with diabetes who were newly prescribed SGLT2 inhibitors. The main outcome was the rate of decline in estimated glomerular filtration rate (eGFR), determined through a linear mixed-effects model with an unstructured covariance structure. RESULTS: The median age of the patients was 52 (Q1-Q3: 47-58) years, and the median fasting plasma glucose and glycated haemoglobin (HbA1c) levels were 144 (Q1-Q3: 124-175) mg/dL and 7.4 (Q1-Q3: 6.8-8.3)%, respectively. The median estimated eGFR was 77.7 (Q1-Q3: 67.2-89.1) mL/min/1.73 m2. The median follow-up period was 1.7 (Q1-Q3: 1.0-2.6) years. Participants were stratified into three groups based on the body mass index change rate tertiles between baseline and 1 year after (tertile 1: <-4.55%, tertile 2: -4.55% to -1.43%, tertile 3: >-1.43%). The annual change in eGFR was -0.78 (-0.94 to -0.63) mL/min/1.73 m2 in tertile 1, -0.95 (-1.09 to -0.81) mL/min/1.73 m2 in tertile 2, and -1.65 mL/min/1.73 m2 (-1.84 to -1.47) in tertile 3 (pinteraction < 0.001). A variety of sensitivity analyses confirmed the relationship between the 1-year body mass index decrease and favourable kidney outcomes after SGLT2 inhibitor administration. CONCLUSIONS: Our analysis of a nationwide epidemiological cohort revealed that kidney outcomes following the initiation of SGLT2 inhibitors would be more favourable, with greater body weight loss observed after the initiation of SGLT2 inhibitors.

Differences in the Association of Lifestyle-Related Modifiable Risk Factors with Incident Cardiovascular Disease Between Individuals with and without Diabetes.

AIMS: Individuals with diabetes have a high risk of developing cardiovascular disease (CVD). Little was known whether the association between modifiable risk factors and incident CVD would change according to the presence of diabetes. METHODS: In this study, we analyzed 4,132,006 individuals including 173,262 individuals (4.2%) with diabetes registered in the JMDC Claims Database, and compared the association between modifiable risk factors and risk of CVD between individuals with and without diabetes. RESULTS: The median age was 44 years, and 57.5% were men. Multivariable Cox regression analyses showed that the relationship of obesity, hypertension, and dyslipidemia with incident CVD was attenuated in individuals with diabetes, whereas that of non-ideal eating habits, smoking, and physical inactivity with incident CVD was pronounced in those with diabetes. The hazard ratio per 1-point increase in non-ideal lifestyle-related factors was 1.03 [95% confidence interval (CI) 1.03-1.04] in individuals with non-diabetes, whereas 1.09 [95% CI 1.07-1.11] in individuals with diabetes (p-value for interaction < 0.001). Further, hazard ratios for developing CVD were 1.02 [95% 1.01-1.04] in individuals not having diabetes, whereas 1.09 [95% CI 1.04-1.13] in individuals having diabetes for the increase of lifestyle-related factor after 1-year follow-up (p-value for interaction 0.007). CONCLUSION: Our analysis utilizing a nationwide epidemiological dataset presented that the relationship of lifestyle-related factors with incident CVD would be pronounced in people having diabetes, suggesting that the maintenance of a healthy lifestyle would play a more important role in the development of CVD in individuals having diabetes. (244 words).

Our investigation utilizing a nationwide epidemiological cohort showed a pronounced relationship of lifestyle-related factors with incident CVD in individuals with diabetes. The HRs (95% CI) for the occurrence of CVD events showed a progressive increase with each additional lifestyle-related factor. This trend was more prominent among individuals with diabetes than those without diabetes. The association between changes in the number of lifestyle-related factors over a year and the risk of developing CVD was also more pronounced in individuals with diabetes. These results suggest that maintaining healthy lifestyle habits would be more important for the CVD prevention in individuals having diabetes.

Current Status and Future Perspective of Onco-Hypertension.

Hypertension and cancer are both increasing with age. Recently, the new concept of "Onco-Hypertension" has been proposed to address the mutual risks posed by hypertension and cancer and to provide comprehensive care for patients with these two conditions in an aging society. Hypertension and cancer share common risk factors and may be interrelated in pathogenesis: hypertension is involved in the development of certain cancers, and cancer survivors have a higher incidence of hypertension. With recent advances in cancer therapy, the number of cancer survivors has increased. Cancer survivors not only have a higher risk of incident hypertension but also an increased risk of future cardiovascular events, highlighting the growing importance of comprehensive care. In this review, we provide an overview of the current status and future perspective of the "Onco-Hypertension," including our research findings.

Macrophages preserve endothelial cell specialization in the adrenal gland to modulate aldosterone secretion and blood pressure.

Macrophages play crucial roles in organ-specific functions and homeostasis. In the adrenal gland, macrophages closely associate with sinusoidal capillaries in the aldosterone-producing zona glomerulosa. We demonstrate that macrophages preserve capillary specialization and modulate aldosterone secretion. Using macrophage-specific deletion of VEGF-A, single-cell transcriptomics, and functional phenotyping, we found that the loss of VEGF-A depletes PLVAP+ fenestrated endothelial cells in the zona glomerulosa, leading to increased basement membrane collagen IV deposition and subendothelial fibrosis. This results in increased aldosterone secretion, called "haptosecretagogue" signaling. Human aldosterone-producing adenomas also show capillary rarefaction and basement membrane thickening. Mice with myeloid cell-specific VEGF-A deletion exhibit elevated serum aldosterone, hypokalemia, and hypertension, mimicking primary aldosteronism. These findings underscore macrophage-to-endothelial cell signaling as essential for endothelial cell specialization, adrenal gland function, and blood pressure regulation, with broader implications for other endocrine organs.

Chronic Tonsillitis and IgA Nephropathy: Findings From a Nationwide Japanese Cohort Study.

RATIONALE & OBJECTIVE: Little is known regarding the association between chronic tonsillitis and the onset of IgA nephropathy (IgAN). In the present study, we examined the potential relationship between chronic tonsillitis and a subsequent risk of developing IgAN. STUDY DESIGN: Observational cohort study. SETTING & PARTICIPANTS: 4,311,393 individuals without a history of IgAN identified between January 2005 and May 2022 within a Japanese nationwide epidemiological database, the JMDC Claims Database, representing health claims to over 60 insurers. EXPOSURE: Comorbid chronic tonsillitis based on diagnosis codes. OUTCOME: IgAN occurrence. ANALYTICAL APPROACH: Cause-specific Cox proportional hazards analysis adjusting for potential confounding factors was employed to estimate hazard ratios (HRs). RESULTS: Comorbid chronic tonsillitis was identified in 12,842 individuals, constituting 0.3% of the cohort. The cohort had a median age of 44 years (IQR, 36-53), and males accounted for 57.9%, with a follow-up of 1,089 days (IQR, 532-1,797), during which 2,653 cases of IgAN developed. Cumulative incidence curve showed a higher cumulative incidence of IgAN in individuals with chronic tonsillitis compared with their counterparts without this condition. Multivariable cause-specific analysis further demonstrated that individuals with chronic tonsillitis had an elevated risk of developing IgAN, with HR of 2.72 (95% CI, 1.79-4.14). LIMITATIONS: Potential residual confounders, and lack of consideration for ethnic distinctions. CONCLUSIONS: Using a large-scale epidemiological dataset, these findings suggest a relationship between chronic tonsillitis and an elevated risk of IgAN development in the general Japanese population. PLAIN-LANGUAGE SUMMARY: IgA nephropathy (IgAN), the most prevalent form of primary glomerulonephritis worldwide, is associated with unfavorable long-term kidney survival and life expectancy. Despite the substantial implications, the early detection of IgAN still remains challenging due to its commonly asymptomatic clinical presentation. Consequently, the exploration of risk factors assumes a critical research priority. Prior studies have reported the potential role of tonsilitis in the pathogenesis of IgAN. In this study, we assessed whether chronic tonsillitis was associated with the subsequent development of IgAN using a nationwide epidemiological dataset incorporating over 4,000,000 individuals. Within this large-scale cohort, our findings revealed an association between a history of tonsillitis and a greater risk of developing IgAN. These findings should heighten awareness of the potential susceptibility of people with chronic tonsilitis to IgAN.

The transcription factor HIF-1α in NKp46+ ILCs limits chronic intestinal inflammation and fibrosis.

Innate lymphoid cells (ILCs) are critical for intestinal adaptation to microenvironmental challenges, and the gut mucosa is characterized by low oxygen. Adaptation to low oxygen is mediated by hypoxia-inducible transcription factors (HIFs), and the HIF-1α subunit shapes an ILC phenotype upon acute colitis that contributes to intestinal damage. However, the impact of HIF signaling in NKp46+ ILCs in the context of repetitive mucosal damage and chronic inflammation, as it typically occurs during inflammatory bowel disease, is unknown. In chronic colitis, mice lacking the HIF-1α isoform in NKp46+ ILCs show a decrease in NKp46+ ILC1s but a concomitant rise in neutrophils and Ly6Chigh macrophages. Single-nucleus RNA sequencing suggests enhanced interaction of mesenchymal cells with other cell compartments in the colon of HIF-1α KO mice and a loss of mucus-producing enterocytes and intestinal stem cells. This was, furthermore, associated with increased bone morphogenetic pathway-integrin signaling, expansion of fibroblast subsets, and intestinal fibrosis. In summary, this suggests that HIF-1α-mediated ILC1 activation, although detrimental upon acute colitis, protects against excessive inflammation and fibrosis during chronic intestinal damage.

Significance of eGFR and proteinuria for cardiovascular disease in individuals beyond 85 years.

BACKGROUND: There are limited data on how advancing age influences prediction of CVD risk based on the estimated glomerular filtration rate (eGFR) and proteinuria, especially in older adults, including those aged ≥ 85 years. This study aimed to clarify the association of eGFR and proteinuria with CVD outcomes and the impact of age on this association. METHODS: The distribution of eGFR and urine protein in Japan was assessed retrospectively using real-world administrative claims and health checkup data collected between April 2014 and November 2022. We investigated the associations of these two parameters with the incidence of CVD, with an emphasis on the impact of aging. RESULTS: We assessed 1 829 020 individuals for distribution of eGFR and proteinuria; after excluding those with known CVD, their association with CVD risk was examined in 1 040 101 individuals aged ≥ 40 years. The prevalence of impaired kidney function (eGFR <60 mL/min/1.73 m2) increased with age, being 0.7%, 9.2%, 21.9%, 40.2%, and 60.2% at the ages of 18-39, 40-64, 65-74, 75-84, and ≥ 85 years (P for trend < 0.001); similarly, the proportion with positive proteinuria increased with age, being 2.7%, 4.3%, 5.6%, 9.2%, and 15.8%, respectively (P for trend < 0.001). Both eGFR and urine protein were identified to be independent risk factors for CVD. Hazard ratios for CVD increased significantly when eGFR was <45 mL/min/1.73 m2 at the ages of 40-64, 65-74, and 75-84 and <30 mL/min/1.73 m2 at ≥ 85 years, while proteinuria remained significantly associated with a high CVD risk regardless of age. These findings were consistent even when analyzed separately by sex. CONCLUSIONS: This study identified eGFR and urine dipstick proteinuria to be independent risk factors for CVD, even among individuals aged ≥ 85 years. However, the contribution of eGFR to the CVD risk was attenuated by aging, whereas proteinuria remained less affected by advancing age.

Nationwide Survey on Transitional Care for Patients With Childhood-Onset Cardiomyopathy in Japan.

Background: Individuals transitioning into adulthood require age-appropriate medical care and delegation of decision-making authority from their parents to the patients themselves. Although there have been multiple observational and interventional studies on transitional care for patients with congenital heart disease (CHD) in the cardiovascular field, transitional care specific to childhood-onset cardiomyopathy (CM) remains unaddressed. Methods and Results: A nationwide questionnaire-based survey was performed in the pediatric cardiology departments of 151 facilities in Japan. Responses were obtained from 100 (66%) facilities with low transfer rates (<5%) for childhood-onset CM cases. The comparison between CHD-transferring and non-CHD-transferring facilities revealed a significantly higher transfer rate (83.9%) for childhood-onset CM cases in the CHD-transferring facilities (P<0.001). Regarding the transition programs, 72 (72%) facilities do not offer any programs for CM, while most (92%) facilities recognize its necessity. Finally, only 19 (19%) facilities provided a transition program, 10 of which were CHD based. Conclusions: To the best of our knowledge, this is the first study to demonstrate the poor transition/transfer care status of patients with childhood-onset CM in Japan. The transfer rate of CMs was lower than that of CHDs, and transition programs were less available. Referring to the system established for CHD could help develop a successful transitional care system for CM.

PNPO-PLP axis senses prolonged hypoxia in macrophages by regulating lysosomal activity.

Oxygen is critical for all metazoan organisms on the earth and impacts various biological processes in physiological and pathological conditions. While oxygen-sensing systems inducing acute hypoxic responses, including the hypoxia-inducible factor pathway, have been identified, those operating in prolonged hypoxia remain to be elucidated. Here we show that pyridoxine 5'-phosphate oxidase (PNPO), which catalyses bioactivation of vitamin B6, serves as an oxygen sensor and regulates lysosomal activity in macrophages. Decreased PNPO activity under prolonged hypoxia reduced an active form of vitamin B6, pyridoxal 5'-phosphate (PLP), and inhibited lysosomal acidification, which in macrophages led to iron dysregulation, TET2 protein loss and delayed resolution of the inflammatory response. Among PLP-dependent metabolism, supersulfide synthesis was suppressed in prolonged hypoxia, resulting in the lysosomal inhibition and consequent proinflammatory phenotypes of macrophages. The PNPO-PLP axis creates a distinct layer of oxygen sensing that gradually shuts down PLP-dependent metabolism in response to prolonged oxygen deprivation.

Novel therapeutic strategies targeting bypass pathways and mitochondrial dysfunction to combat resistance to RET inhibitors in NSCLC.

RET fusion is an oncogenic driver in 1-2 % of patients with non-small cell lung cancer (NSCLC). Although RET-positive tumors have been treated with multikinase inhibitors such as vandetanib or RET-selective inhibitors, ultimately resistance to them develops. Here we established vandetanib resistance (VR) clones from LC-2/ad cells harboring CCDC6-RET fusion and explored the molecular mechanism of the resistance. Each VR clone had a distinct phenotype, implying they had acquired resistance via different mechanisms. Consistently, whole exome-seq and RNA-seq revealed that the VR clones had unique mutational signatures and expression profiles, and shared only a few common remarkable events. AXL and IGF-1R were activated as bypass pathway in different VR clones, and sensitive to a combination of RET and AXL inhibitors or IGF-1R inhibitors, respectively. SMARCA4 loss was also found in a particular VR clone and 55 % of post-TKI lung tumor tissues, being correlated with higher sensitivity to SMARCA4/SMARCA2 dual inhibition and shorter PFS after subsequent treatments. Finally, we detected an increased number of damaged mitochondria in one VR clone, which conferred sensitivity to mitochondrial electron transfer chain inhibitors. Increased mitochondria were also observed in post-TKI biopsy specimens in 13/20 cases of NSCLC, suggesting a potential strategy targeting mitochondria to treat resistant tumors. Our data propose new promising therapeutic options to combat resistance to RET inhibitors in NSCLC.