👤 J Sohn

Vascular damage, including cerebral amyloid angiopathy (CAA) and non-amyloid cerebral small vessel disease (CSVD), has been linked to glymphatic dysfunction, which may contribute to Alzheimer's disease (AD) pathology and cognitive decline. We investigated the associations among vascular damage, glymphatic function measured by the DTI-ALPS (Diffusion Tensor Imaging-Analysis Along the Perivascular Space) index, AD plasma biomarkers, and cognitive decline. This study includes 1,249 participants recruited from Samsung Medical Center. We performed linear regression analysis to identify factors associated with the DTI-ALPS index. Further, linear regression analysis with vascular imaging markers, including CAA and CSVD summary scores, as predictors and DTI-ALPS index as an outcome was performed to investigate the effect of vascular pathology on glymphatic function. We conducted mediation analyses to investigate whether the DTI-ALPS index mediates the effect of vascular imaging markers on plasma biomarkers (phosphorylated tau 217 [p-tau 217], glial fibrillary acidic protein [GFAP], and neurofilament light chain [NFL]). Additionally, mediation analyses with the DTI-ALPS index as a predictor, each plasma biomarker as a mediator, and annual MMSE or CDR-SOB change as an outcome to investigate whether plasma biomarkers mediate the effect of the DTI-ALPS index on longitudinal cognitive decline. First, the DTI-ALPS index was negatively associated with both CAA (β [95% CI] = -0.163 [-0.214, -0.112], p < 0.0001) and CSVD (β [95% CI] = -0.195 [-0.247, -0.143], p < 0.0001) summary scores after controlling for age, sex, BMI status, and APOE genotype. Second, the DTI-ALPS index fully mediated the relationship between these vascular markers and p-tau 217 (CSVD summary score, indirect effect β [95% CI] = 0.016 [0.010, 0.023], p < 0.001; CAA summary score, indirect effect β [95% CI] = 0.013 [0.008, 0.020], p < 0.001) and GFAP (CSVD summary score, indirect effect β [95% CI] = 0.015 [0.008, 0.022], p < 0.001; CAA summary score, indirect effect β [95% CI] = 0.012 [0.007, 0.019], p < 0.001), while partially mediating the relationship for NFL, regardless of Aβ uptake on PET. Finally, the DTI-ALPS index was significantly associated with cognitive decline and this association was partially mediated by plasma biomarkers. These findings highlight glymphatic dysfunction as a key mechanism linking vascular pathology with tau, inflammation and neurodegeneration, independent of Aβ uptakes. Show less

Decreasing body mass index (BMI) from midlife to late life has been linked to increased Alzheimer's disease (AD) risk and cognitive decline; however, the association with in vivo AD pathology remains unclear. This study aimed to clarify the relationship between midlife-to-late-life BMI changes and in vivo AD pathologies, specifically amyloid-β (Aβ), tau, and AD-signature region cerebral glucose metabolism (AD-CM). This observational cohort study included non-demented older adults recruited from the Korean Brain Aging Study for Early Diagnosis and Prediction of Alzheimer’s Disease (KBASE) between January 2014 and December 2020. Participants underwent clinical evaluations and positron emission tomography (PET) imaging to measure brain Aβ, tau, and AD-CM. Midlife BMI was retrospectively estimated from self-reported weight at ages 40–50 years, while late-life BMI was measured during the study. Participants were categorized based on BMI changes as decreasing (≤ − 4%), stable (− 4% to < 4%), or increasing (≥ 4%). Associations between BMI patterns and AD pathologies were analyzed using multiple linear regression models. A total of 268 participants (mean age 66.6 ± 7.9 years; 56.3% women; 22.5% APOE ε4 carriers) were analyzed. Higher midlife BMI correlated significantly with lower AD-CM (β = − 0.009; 95% CI, − 0.015 to − 0.003; A decreasing BMI trajectory from midlife to late life is associated with enhanced AD-related neurodegeneration, underscoring the clinical importance of monitoring long-term body weight changes in relation to Alzheimer's disease pathophysiology. The online version contains supplementary material available at 10.1186/s13195-026-01967-z. Show less

Approximately 40% of patients with hormone receptor-positive (HR+), human epidermal growth factor receptor 2-negative (HER2-), advanced breast cancer (ABC) have PIK3CA alterations, which contributes to endocrine therapy resistance. Alpelisib, an α-selective phosphatidylinositol 3-kinase inhibitor and degrader, given in combination with fulvestrant, is approved for the treatment of PIK3CA-mutated, HR+, HER2- ABC, based on the SOLAR-1 trial. Aside from PIK3CA, other gene alterations are associated with poor prognosis and limited response to treatment in this patient population. In this retrospective analysis, we performed tissue-based next-generation sequencing of 398 patients (237 PIK3CA-altered, 161 PIK3CA-wild type) from SOLAR-1. Progression-free survival (PFS) correlative analysis was performed in the PIK3CA-altered cohort. PIK3CA-altered and PIK3CA-wild type tumors had distinct genomic profiles. In the PIK3CA-altered cohort, patients who received alpelisib plus fulvestrant had a median PFS (mPFS) of 11.01 months versus 5.55 months for those receiving placebo plus fulvestrant (P=0.0004). Patients in the lowest tumor mutational burden quartile as well as those with FGFR1 or FGFR2 alterations derived greater PFS benefit from alpelisib plus fulvestrant versus placebo plus fulvestrant (18.5 versus 3.22 months; HR 0.38; 95% CI 0.21-0.68. FGFR1 12.71 versus 3.75 months; HR 0.38; 95% CI 0.17-0.81; P=0.32. FGFR2: 9.63 versus 2.78 months; HR 0.31; 95% CI 0.1-0.94; P=0.29); patients with MYC or RAD21 alterations derived limited PFS benefit. Cox and multi-task machine learning models identified lower Eastern Cooperative Oncology Group performance status, prior cyclin-dependent kinase 4/6 inhibitor (CDK4/6i) treatment, and PTEN or TP53 alterations among the most deleterious factors for PFS in the PIK3CA-altered cohort. Alpelisib plus fulvestrant provides clinical benefit for patients with PIK3CA-altered, HR+, HER2- ABC across a range of concomitant alterations, including those previously implicated in endocrine therapy or CDK4/6i resistance. Machine learning models identified factors including gene mutations that influenced PFS. Show less

Inflammatory bowel disease (IBD) is an immune-mediated disorder driven by overactivation of autotaxin (ATX), which elevates lysophosphatidic acid (LPA) signaling and suppresses autophagy, exacerbating intestinal inflammation. Given the pivotal role of autophagy in maintaining intestinal homeostasis, inhibiting ATX offers a dual therapeutic mechanism by both restoring autophagic activity and attenuating LPA-mediated inflammatory responses. Current treatments are hindered by nonspecific immunosuppression and frequent systemic side effects, underscoring the need for targeted, multifunctional therapeutic strategies. Here, we present a dual-functional nanotherapeutic platform, ATX-scavenging liposomes loaded with rapamycin (AS-Lipo@R), engineered for the oral treatment of acute colitis. Our proposed formulation incorporates BMP-22, a lipid ATX inhibitor that simultaneously functions as a structural building block of the liposomal membrane. Rapamycin, an autophagy activator, is encapsulated within the bilayer of liposomes. We confirmed that AS-Lipo@R exhibits strong binding affinity to extracellular ATX and mediates its lysosomal degradation upon cellular internalization, thereby demonstrating its ATX-scavenging property. In vitro, AS-Lipo@R inhibited inflammatory macrophage activation, promoted M2 macrophage polarization, and substantially restored autophagic activity in LPS/IFN-γ-stimulated macrophages. In vivo, oral administration of AS-Lipo@R led to preferential accumulation in ATX-overexpressing inflamed colonic tissue, resulting in reduced pro-inflammatory cytokine production, recovered autophagy, and enhanced intestinal barrier integrity in colitis mice. These findings highlight AS-Lipo@R as a synergistic and targeted nanomedicine that simultaneously modulates ATX and autophagy pathways, offering novel insights into immunomodulatory strategies for IBD treatment. Show less

This study aimed to identify different symptom profiles of complicated grief/bereavement-related posttraumatic stress disorder (PTSD) and examine the associations with social life factors, posttraumatic growth, and quality of life in a sample of parents whose children died in Sewol ferry accident. A total of 272 bereaved parents affected by the Sewol ferry accident participated and completed self-report scales about traumatic loss-related symptoms. The latent profile analysis (LPA) of complicated grief and posttraumatic symptoms was classified. To examine the predictors (interpersonal stress/familial conflict/social support) and outcomes (posttraumatic growth/quality of life) of the traumatic loss symptom profiles, an automatic three-step approach was chosen. The LPA identified three symptom profiles of complicated grief and posttraumatic stress: low symptomatology group (30.4%), moderate symptomatology group (49.6%), and high symptomatology group (20.0%). Higher perceived interpersonal stress significantly increased the odds of moderate and high symptomatology, while higher family stress was a significant predictor for high symptomatology compared to both low and moderate symptomatology groups. In addition, higher perceived social support significantly decreased the odds of being in both moderate and high symptomatology groups compared to the low group. The low symptomatology group showed the highest quality of life, followed by the moderate and high groups. Posttraumatic growth was also significantly different between the classes, with the moderate symptomatology group reporting higher growth than the low symptomatology group. Our findings suggest that managing the mental health of people who have experienced a traumatic loss will be a critical component of their quality of life in the future. In addition, interventions to help reduce family conflict and interpersonal stress may be necessary to reduce difficulties associated with psychopathology. Show less

Lipoproteins are essential for lipid transport in all bilaterians. A single Apolipoprotein B (ApoB) molecule is the inseparable structural scaffold of each ApoB-containing lipoprotein (B-lps), which are responsible for transporting lipids to peripheral tissues. The cellular mechanisms that regulate ApoB and B-lp production, secretion, transport, and degradation remain to be fully defined. In humans, elevated levels of vascular B-lps play a causative role in cardiovascular disease. Previously, we have detailed that human B-lp biology is remarkably conserved in the zebrafish using an Show less

We assessed the coverage of molecular drug susceptibility testing (mDST) among patients with pulmonary multidrug/rifampicin-resistant tuberculosis (MDR/RR-TB) in South Korea and identified factors influencing the lack of mDST implementation. This retrospective study included patients with pulmonary MDR/RR-TB who initiated tuberculosis (TB) treatment between January 2015 and September 2021. Data were obtained from the K-TB-N cohort, an integrated national TB database linking three datasets. We assessed mDST coverage, temporal trends and factors associated with the lack of mDST implementation. mDST was defined as the use of the Xpert MTB/RIF assay or line probe assay (LPA) for isoniazid and rifampicin (first-line LPA). In total, 4637 patients were included in the analysis. Of the 4637 patients, 1342 (28.9%) did not undergo mDST; whereas, 3295 (71.1%) underwent mDST. Over the study period, a statistically significant annual increase in mDST coverage was observed, escalating from 49.1% in 2015 to 96.9% in 2021 (p<0.001). Throughout the study, the coverage of the Xpert MTB/RIF assay remained lower than that of LPA (22.1% vs 64.2%, p<0.001). Multivariable logistic regression analysis identified several factors independently associated with a decreased likelihood of mDST being conducted, including TB treatment initiation in secondary general hospitals, small hospitals or primary clinics, as well as in non-public-private mix (PPM) participating institutions. In addition, transfers between PPM-participating and non-participating institutions during the treatment period and sputum acid-fast bacilli smear-negative status were significantly associated with lower mDST uptake. Although the increasing mDST coverage is a positive development, further efforts are needed to achieve nationwide and universal implementation, particularly for the Xpert MTB/RIF assay, in South Korea. Show less

Melanocortin-4 receptors (MC4Rs) expressed by the central nervous system are essential regulators of energy homeostasis, and Mc4r mutation is the most common cause of human monogenic obesity. Notably, patients with obesity carrying Mc4r mutations are protected against obesity-induced hypertension, and MC4R agonists elevate blood pressure (BP). Although increased sympathetic tone by MC4Rs is suggested to underlie this phenotype, the detailed mechanisms remain unclear. Here, we investigate how MC4Rs regulate the sympathetic preganglionic neurons and find that MC4Rs activate these neurons via the protein kinase A-dependent activation of the transient receptor potential vanilloid 1 (TRPV1) channel. Importantly, we demonstrate that the inhibition of TRPV1 prevents MC4R-induced elevation of BP but does not affect MC4R-induced anorexia. We further show that TRPV1 is responsible for MC4R-dependent activation of the sympathetic preganglionic neurons by high-fat diet. Together, our results provide insight into how MC4Rs regulate sympathetic function. Show less

Atypical antipsychotics such as risperidone cause drug-induced metabolic syndrome. However, the underlying mechanisms remain largely unknown. Here, we report a new mouse model that reliably reproduces risperidone-induced weight gain, adiposity, and glucose intolerance. We found that risperidone treatment acutely altered energy balance in C57BL/6 mice and that hyperphagia accounted for most of the weight gain. Transcriptomic analyses in the hypothalamus of risperidone-fed mice revealed that risperidone treatment reduced the expression of Mc4r. Furthermore, Mc4r in Sim1 neurons was necessary for risperidone-induced hyperphagia and weight gain. Moreover, we found that the same pathway underlies the obesogenic effect of olanzapine-another commonly prescribed antipsychotic drug. Remarkably, whole-cell patch-clamp recording demonstrated that risperidone acutely inhibited the activity of hypothalamic Mc4r neurons via the opening of a postsynaptic potassium conductance. Finally, we showed that treatment with setmelanotide, an MC4R-specific agonist, mitigated hyperphagia and obesity in both risperidone- and olanzapine-fed mice. Show less

Skeletal dysplasia (SD), a heterogeneous disease group with rare incidence and various clinical manifestations, is associated with multiple causative genes. For clinicians, accurate diagnosis of SD is clinically and genetically difficult. The development of next-generation sequencing (NGS) has substantially aided in the genetic diagnosis of SD. In this study, we conducted a targeted NGS of 437 genes - included in the nosology of SD published in 2019 - in 31 patients with a suspected SD. The clinical and genetic diagnoses were confirmed in 16 out of the 31 patients, and the diagnostic yield was 51.9%. In these patients, 18 pathogenic variants were found in 13 genes ( Show less

Fructose malabsorption is a common digestive disorder in which absorption of fructose in the small intestine is impaired. An abnormality of the main intestinal fructose transporter proteins has been proposed as a cause for fructose malabsorption. However the underlying molecular mechanism for this remains unclear. In this study, we investigated whether carbohydrate response element-binding protein (ChREBP) plays a role in intestinal fructose absorption through the regulation of genes involved in fructose transport and metabolism and ion transport. Wild type (WT) and Chrebp knockout (KO) mice (6 or 8 weeks old) were fed a control diet (55% starch, 15% maltodextrin 10) or high-fructose diet (HFrD, 60% fructose, 10% starch) for 3-12 days. Body weight and food intake were measured, signs of fructose malabsorption were monitored, and the expression of genes involved in fructose transport/metabolism and ion transport was evaluated. Furthermore, transient transfection and chromatin immunoprecipitation were performed to show the direct interaction between ChREBP and carbohydrate response elements in the promoter of Slc2A5, which encodes the fructose transporter GLUT5. Chrebp KO mice fed the control diet maintained a constant body weight, whereas those fed a HFrD showed significant weight loss within 3-5 days. In addition, Chrebp KO mice fed the HFrD exhibited a markedly distended cecum and proximal colon containing both fluid and gas, suggesting incomplete fructose absorption. Fructose-induced increases of genes involved in fructose transport (GLUT5), fructose metabolism (fructokinase, aldolase B, triokinase, and lactate dehydrogenase), and gluconeogenesis (glucose-6-phosphatase and fructose-1,6-bisphosphatase) were observed in the intestine of WT but not of Chrebp KO mice. Moreover the Na ChREBP plays a key role in the dietary fructose transport as well as conversion into lactate and glucose through direct transcriptional control of genes involved in fructose transport, fructolysis, and gluconeogenesis. Moreover, ablation of Chrebp results in a severe diarrhea in mice fed a high-fructose diet, which is associated with the insufficient induction of GLUT5 in the intestine. Show less

Differentiation and maturation of oligodendrocyte progenitor cells (OPCs) involve the assembly and disassembly of actin microfilaments. However, how actin dynamics are regulated during this process remains poorly understood. Leucine-rich repeat and Ig-like domain-containing Nogo receptor interacting protein 1 (LINGO-1) is a negative regulator of OPC differentiation. We discovered that anti-LINGO-1 antibody-promoted OPC differentiation was accompanied by upregulation of cytoplasmic gelsolin (cGSN), an abundant actin-severing protein involved in the depolymerization of actin filaments. Treating rat OPCs with cGSN siRNA reduced OPC differentiation, whereas overexpression of cGSN promoted OPC differentiation Show less

DNA methylation changes in peripheral blood DNA have been shown to be associated with solid tumors. We sought to identify methylation alterations in whole blood DNA that are associated with breast cancer (BC). Epigenome-wide DNA methylation profiling on blood DNA from BC cases and healthy controls was performed by applying Infinium HumanMethylation450K BeadChips. Promising CpG sites were selected and validated in three independent larger sample cohorts via MassARRAY EpiTyper assays. CpG sites located in three genes (cg06418238 in RPTOR, cg00736299 in MGRN1 and cg27466532 in RAPSN), which showed significant hypomethylation in BC patients compared to healthy controls in the discovery cohort (p < 1.00 x 10-6) were selected and successfully validated in three independent cohorts (validation I, n =211; validation II, n=378; validation III, n=520). The observed methylation differences are likely not cell-type specific, as the differences were only seen in whole blood, but not in specific sub cell-types of leucocytes. Moreover, we observed in quartile analysis that women in the lower methylation quartiles of these three loci had higher ORs than women in the higher quartiles. The combined AUC of three loci was 0.79 (95%CI 0.73-0.85) in validation cohort I, and was 0.60 (95%CI 0.54-0.66) and 0.62 (95%CI 0.57-0.67) in validation cohort II and III, respectively. Our study suggests that hypomethylation of CpG sites in RPTOR, MGRN1 and RAPSN in blood is associated with BC and might serve as blood-based marker supplements for BC if these could be verified in prospective studies. Show less

Legionella pneumophila, a human intracellular pathogen, encodes about 290 effector proteins that are translocated into host cells through a secretion machinery. Some of these proteins have been shown to manipulate or subvert cellular processes during infection, but functional roles of a majority of them remain unknown. Lpg0393 is a newly identified Legionella effector classified as a hypothetical protein. Through X-ray crystallographic analysis, we show that Lpg0393 contains a Vps9-like domain, which is structurally most similar to the catalytic core of human Rabex-5 that activates the endosomal Rab proteins Rab5, Rab21 and Rab22. Consistently, Lpg0393 exhibited a guanine-nucleotide exchange factor activity toward the endosomal Rabs. This work identifies the first example of a bacterial guanine-nucleotide exchange factor that is active towards the Rab5 sub-cluster members, implying that the activation of these Rab proteins might be advantageous for the intracellular survival of Legionella. Show less

This study was conducted to evaluate the protective mechanisms of Nelumbinis semen (NS) on lipopolysaccharide (LPS)-induced activation of BV-2 microglial cells. The anti-inflammatory effects of NS were determined by analyzing nitric oxide production and proinflammatory cytokines using enzyme-linked immunosorbent assay. The mechanism was evaluated in BV-2 cells with or without NS treated with LPS for various lengths of time using oligonucleotide microarray and real time reverse transcription-polymerase chain reaction. The oligonucleotide microarray analysis revealed that mitogen activated protein kinase (MAPK) signaling pathway-related genes such as Fgfr3, Fgf12, Rasal2, Nfkb2, Map2k5, Mapk1, Map3k7, and NFatc2 were down-regulated in LPS activated BV-2 cells by pretreatment with NS. In addition, significant decreases in Nos1ap gene expression were observed with NS pretreatment. Cluster linked pathway analysis using the Kyoto Encyclopedia of Genes and Genomes database revealed that the effects of NS were closely associated with the regulation of mitochondria functions. These results suggested that NS can affect the MAPK signaling pathway and mitochondrial functions in BV-2 cells activated with LPS. Show less