👤 Juan Ramon Gonzalez

Posttraumatic stress disorder (PTSD) has been associated with accelerated cognitive aging and increased risk for Alzheimer's disease (AD) and related dementias (ADRD), yet the neural substrates linking trauma-related psychiatric illness to late-life neurodegenerative vulnerability remain poorly defined. The amygdala plays a central role in threat processing and emotional memory and exhibits persistent hyperactivity in PTSD, but its molecular and pathological state in aging individuals with PTSD has not been systematically examined. Postmortem amygdala tissue from older adult donors (≥ 70 years) with lifetime PTSD (n = 5) and age-matched controls (n = 5) was obtained from the National PTSD Brain Bank. A multimodal analysis was performed integrating immunohistochemical quantification of β-amyloid and phosphorylated tau pathology, targeted transcriptional profiling of AD-related genes, gene network analysis, and protein quantification of pathological, inflammatory, and synaptic markers. PTSD cases showed enrichment of combined tau-amyloid pathology within the amygdala and significantly greater β-amyloid burden. Targeted transcriptomic profiling identified coordinated upregulation of AD-related genes involved in amyloid processing, lipid metabolism, proteostasis, and inflammatory signaling. Network analysis revealed an APP-centered molecular architecture with APOE, MAPT, and CLU functioning as highly connected secondary hubs. Protein analyses demonstrated increased amyloid-β and pTau231 abundance, selective markers of gliosis, and synaptic alterations characterized by elevated excitatory receptor expression and reduced inhibitory GABABR1a. Older adults with PTSD exhibit convergent evidence of AD-relevant molecular and pathological remodeling in the amygdala. These findings suggest that chronic trauma-related circuit dysregulation may intersect with aging-associated inflammatory and synaptic processes, creating a biological environment permissive for neurodegenerative vulnerability in emotionally salient brain circuits. Show less

Apolipoprotein E (APOE) alleles are well-established genetic risk factors for Alzheimer's disease (AD), but their effects on AD biomarkers (amyloid beta [Aβ]42/40, phosphorylated tau [p-tau]181, neurofilament light chain [NfL], and glial fibrillary acidic protein [GFAP]) may vary across populations due to ancestry-, age-, and sex-related differences. We hypothesized that these effects vary across Hispanic/Latino background groups with distinct ancestral admixture. We analyzed ε2 and ε4 allele associations with AD biomarkers using survey-weighted linear regression models, adjusting for demographic covariates. Secondary analyses examined genetic analysis group- and ancestry-specific effects. ε4 was associated with lower Aβ42/40 and higher p-tau181and GFAP levels, but not with NfL, suggesting its role in Aβ and tau deposition and neuroinflammation. ε4 associations were stronger in those with higher European and lower African ancestry. These findings expand on prior studies suggesting that genetic ancestry modifies APOE-associated AD risk in Hispanic/Latino populations and highlight the importance of capturing ancestry-based heterogeneity in AD biomarker research. Show less

The apolipoprotein E (APOE) ε4 allele represents the strongest genetic risk factor for Alzheimer's disease (AD), but its role in genetically diverse Latin American and Caribbean (LAC) populations is underexplored. We conducted a meta-analysis of 35 studies from 11 LAC countries, encompassing 3206 patients with AD and 5515 controls. The ε4 allele demonstrated significant association with increased AD risk (odds ratio [OR] = 3.25, 95% confidence interval [2.82-3.76]), while ε3 showed lower odds (0.42, [0.37-0.48]). Homozygous ε4/ε4 carriers had elevated risk (6.84, [5.09-9.19]), and heterozygous ε3/ε4 carriers showed moderate risk (2.59, [2.31-2.91]). Country-level analyses revealed variability, with Ecuador showing the highest OR for ε4/ε4 (13.29, [1.56-113.4]). These results confirm APOE ε4 as a major AD risk factor in LAC populations and highlight regional differences relevant to precision medicine. Show less

The purpose of this study was to estimate the prevalence and number of cerebral microbleeds (CMBs) in a Hispanic and Latino cohort from various self-identified backgrounds and test associations with age, vascular risk factors, APOE (apolipoprotein E), and cognitive function. The 3T brain magnetic resonance imaging exams were obtained on SOL-INCA-MRI (Study of Latinos-Investigation of Neurocognitive Aging-MRI) magnetic resonance imaging study participants, a community-based study. CMB number was counted and categorized as: (1) any CMB, (2) lobar only, (3) deep only, (4) mixed, (5) deep+mixed, and (6) lobar+mixed. We examined whether prevalence of CMBs varied by age, sex, education, Hispanic background, cardiovascular risk factors (hypertension, diabetes, Framingham Risk Score), APOE genotype, and cognition. A total of 2455 participants were included who were 63.0±8.4 years of age, 67.9% women, and 62.2% high school education or higher. CMBs prevalence was 11.7% (8.3% lobar only, 2.0% deep only, 1.4% mixed locations). After adjusting for age, sex, and education, a high Framingham Risk Score was associated with the presence of CMBs of all types, except lobar only. Prevalent stroke/transient ischemic attack was associated with higher likelihood of deep-only CMBs. For participants with cognitive impairment, the adjusted prevalence of mixed CMBs (2.2% versus 1.1%, High vascular risk scores, self-reported history of stroke/transient ischemic attack, and cognitive status were associated with a higher likelihood of CMBs, especially in deep regions. Show less

Air pollution exposure is associated with increased cardiovascular morbidity and mortality worldwide. Previous studies provide a causal relationship between exposure to particulate matter (PM) and atherosclerosis development. We have previously demonstrated increased aortic atherosclerosis and adverse metabolic effects in hyperlipidemic mice exposed to ambient ultrafine PM. However, the underlying mechanisms by which ambient PM promotes systemic effects leading to worsened atherosclerosis remain unknown. We have recently shown that the gut microbiota composition was altered in mice exposed to re-aerosolized PM in the ultrafine-size range for 10 weeks. We hypothesized that sub-chronic exposure to ultrafine PM induces gut dysbiosis in association with systemic prooxidative effects and atherosclerotic lesion development. Male apolipoprotein E knockout (ApoE Show less

Familial chylomicronemia syndrome (FCS) is a rare autosomal recessive disorder characterized by extreme hypertriglyceridemia (>1000 mg/dL), recurrent pancreatitis, and lipoprotein lipase (LPL) deficiency. FCS is caused by biallelic loss-of-function variants in LPL or in 4 other genes encoding its cofactors and regulators, including LMF1 (lipase maturation factor 1). Variants in LMF1 are rare and present only in 1% to 2% of the FCS cases. To assess in 3 patients with severe hypertriglyceridemia and recurrent pancreatitis and in whom a homozygous LMF1 duplication, initially classified as a variant of uncertain significance (VUS) was identified, post-heparin LPL activity. We collected demographics, fasting lipid profiles, and body mass index, and performed next-generation sequencing using a targeted panel that included canonical FCS genes. A homozygous in-frame duplication in LMF1 (c.914₉₂₈dup; p.Ser309_Phe310dup) was identified. Variants were classified according to American College of Medical Genetics and Genomics/Association for Molecular Pathology (ACMG/AMP) guidelines and cross-referenced with public archive of reports of the relationships among human variations and phenotypes (ClinVar), The Human Gene Mutation Database at the Institute of Medical Genetics in Cardiff (HGMD), Leiden Open Variation Database (LOVD), The Single Nucleotide Polymorphism database (dbSNP), The Genome Aggregation Database (gnomAD), and in-house databases. LPL activity was assessed in post-heparin plasma using a radiometric assay. All 3 patients were homozygous for c.914₉₂₈dup (this variant was classified as a VUS) and exhibited markedly reduced LPL activity (<20% of normal). Clinical manifestations were consistent with FCS, including extreme triglyceride elevations and recurrent pancreatitis. One patient died from fulminant pancreatitis. The combined clinical, biochemical, and genetic evidence supports the reclassification of LMF1 c.914₉₂₈dup (p.Ser309_Phe310dup) as likely pathogenic according to ACMG/AMP guidelines and indicates its association with severe pancreatitis. Show less

Chronic alcohol drinking increases susceptibility to cognitive impairment; however, the underlying mechanisms remain unclear. In this study, we investigated the effects of chronic alcohol drinking on working and recognition memory in a Marchigian Sardinian alcohol-preferring (msP) rat line. Due to interest in insulin-based medications for alcohol use disorder, we examined insulin/insulin-like growth factor 1 (IGF-1) genes in the prelimbic (PL) and infralimbic (IL) medial prefrontal cortex, a region linked to alcohol dependence and cognition. Male and female msPs received access to alcohol (20% v/v) and water (H Show less

Longer-term effects of chiropractic care on neuroplasticity, stress, and immune biomarkers remain unclear. This study evaluates the effects of chiropractic care on physiological biomarkers, including brain-derived neurotrophic factor (BDNF), cortisol (saliva, blood, hair), and inflammatory cytokines [interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), interferon-gamma (IFN-γ), C-reactive protein (CRP), B-lymphocytes (CD19), T-helper cells (CD4), cytotoxic T cells (CD8), and natural killer cells (CD56)] in subclinical spinal pain patients. Parallel-group, pragmatic randomized controlled trial conducted at the Rehabilitation Center of Railway General Hospital, Rawalpindi, Pakistan. Intervention: 12 weeks; follow-up: 16 weeks (May-December 2022). Participants with subclinical spinal pain were randomly assigned by using simple lottery method to either 12 weeks of chiropractic or sham care. We aimed to recruit up to 150 participants over three months; however, given the pragmatic nature of the trial and logistical constraints, including the availability of chiropractors, the final number enrolled was determined by how many eligible participants could be recruited during this time. Adults aged 20-60 years with subclinical spinal pain (n = 106 randomized; 88 completed 12-week measures; 73 completed 16-week follow-up). Among those who finished 12 weeks: chiropractic, 26 males/15 females, mean age 37.49 ± 12.39 years; sham, 24 males/23 females, mean age 26.85 ± 7.13 years. The primary outcome blood BDNF and secondary outcome, including saliva, blood and hair cortisol, IL-6, TNF-α, IFN-γ, CRP, CD19, CD4, CD8, and CD56 levels were measured at baseline, after 12 weeks of intervention, and at a 16-week follow-up. Linear and linear mixed-effects regression models were used to assess the effect of care and time on biological measures. Significant between-group differences were observed after 12 weeks of intervention, with higher salivary cortisol 5 ± 2 [0, 10], p = 0.045 and blood BDNF150 ± 60 (40, 270), p = 0.009 and IL-6 1.0 ± 0.3 [0.5, 1.5], p < 0.001 levels in the chiropractic care group. At the 16-week follow-up, blood cortisol -9 ± 4 [-17, -1], p = 0.024, IFN-γ - 22 ± 7 [-35, -9], and TNF-α -2 ± 1 [-5, 0], p = 0.028 levels increased in the sham group. Within-group comparisons showed a non-significant 10 ± 20 [-20, 50], p = 0.439 reduction in hair cortisol levels in the chiropractic group at 12 weeks, along with increased levels of blood cortisol, BDNF, CD8, CD4, IL-6, and CD19. 12 weeks of Chiropractic care modulates biomarkers linked to neuroplasticity, inflammation, and stress. Increases in brain-derived neurotrophic factor and interleukin-6 suggest enhanced neuroplasticity and inflammatory responses, while decreases in tumor necrosis factor-alpha indicate a regulatory effect on systemic inflammation. These findings support the notion that chiropractic care modulates physiological systemic biomarkers, which may underscore its benefits on clinical outcomes. ClinicalTrials.gov NCT05369156. Show less

Blood-based biomarkers hold promise as a minimally invasive tool for identifying early signs of Alzheimer's disease pathology and neurodegeneration. We investigated associations between plasma biomarkers of amyloid-beta, tau, neuroaxonal injury, and glial activation with cognitive performance among community-dwelling Hispanic/Latino adults in the United States. We analyzed cross-sectional data from 5730 adults aged 50 years and older (unweighted; mean [SD], 63.5 [8.2] years) in the Study of Latinos-Investigation of Neurocognitive Aging (SOL-INCA; 2016-2018). Plasma concentrations of amyloid-beta (Aβ Here we show higher ln(pTau-181) and ln(NfL) are associated with lower global cognitive performance (b Plasma biomarkers related to Alzheimer's disease pathophysiology and broader neurodegenerative processes are associated with cognitive performance among Hispanic/Latino adults. These findings highlight the potential utility of blood-based biomarkers for identifying early cognitive vulnerability in this population. Show less

Type 1 diabetes (T1D) results from autoimmune destruction of pancreatic β-cells. Current therapies fail to address the multiple mechanisms driving disease progression. We developed an oral Female non-obese diabetic (NOD) mice were treated with the oral vaccine, GAST-17, or their combination. Blood glucose levels, islet histology, immune cell infiltration, cytokine profiles, and regulatory T cell populations were assessed. Functional assays included antigen-specific stimulation, adoptive transfer, and analysis of immunoregulatory gene expression. Combination therapy demonstrated superior efficacy in both diabetes reversal and prevention. In reversal studies, diabetes remission was achieved in 80% of mice receiving the combination therapy, compared with 63% in the vaccine-only group and 5% in the GAST-17-only group. In prevention studies, diabetes onset was prevented in 80% of mice receiving the combination therapy, compared with 70% in the vaccine-only group and 30% in the GAST-17-only group. Therapeutic effects were associated with increased antigen-specific regulatory T-cells, reduced islet-infiltrating lymphocytes, preserved insulin-positive islet area and β-cell mass, and modulation of cytokine profiles, including elevated IL-10 and TGF-β and reduced IFN-γ, GM-CSF, IL-1α, and IL-12. Upregulation of immune checkpoint molecules (CTLA-4 and PD-L1) and immunoregulatory mediators (AhR, IDO, and IL-27) was observed, suggesting a potential contribution to immune homeostasis. The combination of the oral Show less

Citrin deficiency (CD) is caused by the inactivation of SLC25A13, a mitochondrial membrane protein required to move electrons from cytosolic NADH to the mitochondrial matrix in hepatocytes. People with CD do not like sweets. Here we show that SLC25A13 loss causes the accumulation of glycerol-3-phosphate (G3P), which activates the carbohydrate response element-binding protein (ChREBP) to transcribe FGF21, which acts in the brain to restrain intake of sweets and alcohol and to transcribe key genes driving lipogenesis. Mouse and human data suggest that G3P-ChREBP is a mechanistic component of the Randle Cycle that contributes to metabolic-dysfunction-associated steatotic liver disease and forms part of a system that communicates metabolic states from the liver to the brain in a manner that alters food and alcohol choices. The data provide a framework for understanding FGF21 induction in varied conditions, suggest ways to develop FGF21-inducing drugs and suggest potential drug candidates for lean metabolic-dysfunction-associated steatotic liver disease and support of urea cycle function in CD. Show less

Nuclear hormone receptors exist in dynamic equilibrium between transcriptionally active and inactive complexes dependent on interactions with ligands, proteins, and chromatin. The present studies examined the hypothesis that endogenous ligands activate peroxisome proliferator-activated receptor-β/δ (PPARβ/δ) in keratinocytes. The phorbol ester treatment or HRAS infection of primary keratinocytes increased fatty acids that were associated with enhanced PPARβ/δ activity. Fatty acids caused PPARβ/δ-dependent increases in chromatin occupancy and the expression of angiopoietin-like protein 4 ( Show less

Pediatric classic Hodgkin lymphoma (cHL) patients have a high survival rate but suffer from severe long-term side effects induced by chemo- and radiotherapy. cHL tumors are characterized by the low fraction (0.1%-10%) of malignant Hodgkin and Reed-Sternberg (HRS) cells in the tumor. The HRS cells depend on the surrounding immune cells for survival and growth. This dependence is leveraged by current treatments that target the PD-1/PD-L1 axis in cHL tumors. The development of more targeted therapies that are specific for the tumor and are therefore less toxic for healthy tissue compared with conventional chemotherapy could improve the quality of life of pediatric cHL survivors. Here, we applied single-cell RNA sequencing (scRNA-seq) on isolated HRS cells and the immune cells from the same cHL tumors. Besides Show less

Vascular dysfunction and capillary leak are common in critically ill COVID-19 patients, but identification of endothelial pathways involved in COVID-19 pathogenesis has been limited. Angiopoietin-like 4 (ANGPTL4) is a protein secreted in response to hypoxic and nutrient-poor conditions that has a variety of biological effects including vascular injury and capillary leak. To assess the role of ANGPTL4 in COVID-19-related outcomes. Two hundred twenty-five COVID-19 ICU patients were enrolled from April 2020 to May 2021 in a prospective, multicenter cohort study from three different medical centers, University of Washington, University of Southern California and New York University. Plasma ANGPTL4 was measured on days 1, 7, and 14 after ICU admission. We used previously published tissue proteomic data and lung single nucleus RNA (snRNA) sequencing data from specimens collected from COVID-19 patients to determine the tissues and cells that produce ANGPTL4. Higher plasma ANGPTL4 concentrations were significantly associated with worse hospital mortality (adjusted odds ratio per log ANGPTL4 is expressed in pulmonary epithelial cells and fibroblasts and is associated with clinical prognosis in critically ill COVID-19 patients. Show less

Coronary angiography is the primary procedure for diagnosis and management decisions in coronary artery disease (CAD), but ad-hoc visual assessment of angiograms has high variability. Here we report a fully automated approach to interpret angiographic coronary artery stenosis from standard coronary angiograms. Using 13,843 angiographic studies from 11,972 adult patients at University of California, San Francisco (UCSF), between April 1, 2008 and December 31, 2019, we train neural networks to accomplish four sequential necessary tasks for automatic coronary artery stenosis localization and estimation. Algorithms are internally validated against criterion-standard labels for each task in hold-out test datasets. Algorithms are then externally validated in real-world angiograms from the University of Ottawa Heart Institute (UOHI) and also retrained using quantitative coronary angiography (QCA) data from the Montreal Heart Institute (MHI) core lab. The CathAI system achieves state-of-the-art performance across all tasks on unselected, real-world angiograms. Positive predictive value, sensitivity and F1 score are all ≥90% to identify projection angle and ≥93% for left/right coronary artery angiogram detection. To predict obstructive CAD stenosis (≥70%), CathAI exhibits an AUC of 0.862 (95% CI: 0.843-0.880). In UOHI external validation, CathAI achieves AUC 0.869 (95% CI: 0.830-0.907) to predict obstructive CAD. In the MHI QCA dataset, CathAI achieves an AUC of 0.775 (95%. CI: 0.594-0.955) after retraining. In conclusion, multiple purpose-built neural networks can function in sequence to accomplish automated analysis of real-world angiograms, which could increase standardization and reproducibility in angiographic coronary stenosis assessment. Show less

Mitochondrial dysfunction is a well-known contributor to aging and age-related diseases. The precise mechanisms through which mitochondria impact human lifespan, however, remain unclear. We hypothesize that humans with exceptional longevity harbor rare variants in nuclear-encoded mitochondrial genes (mitonuclear genes) that confer resistance against age-related mitochondrial dysfunction. Here we report an integrated functional genomics study to identify rare functional variants in ~ 660 mitonuclear candidate genes discovered by target capture sequencing analysis of 496 centenarians and 572 controls of Ashkenazi Jewish descent. We identify and prioritize longevity-associated variants, genes, and mitochondrial pathways that are enriched with rare variants. We provide functional gene variants such as those in MTOR (Y2396Lfs*29), CPS1 (T1406N), and MFN2 (G548*) as well as LRPPRC (S1378G) that is predicted to affect mitochondrial translation. Taken together, our results suggest a functional role for specific mitonuclear genes and pathways in human longevity. Show less

Nickel-induced proliferation or cytokine release by peripheral blood mononuclear cells may be used for in vitro diagnosis of nickel allergy. Aim of this study was to explore the nickel-specific cytokine profile to further elucidate the pathogenesis of nickel allergic contact dermatitis (ACD) and to identify potential new biomarkers for nickel ACD. Peripheral blood mononuclear cells from patients and controls were cultured with T-cell skewing cytokine cocktails and/or nickel. Cytokine and chemokine concentrations were assessed in culture supernatants using validated multiplex assays. Specific cytokine production was related to history of nickel allergy and patch-test results. Twenty-one of the 33 analytes included in the analysis were associated with nickel allergy and included type1 (TNF-α, IFN-γ, TNF-β), type 2 (IL-3, IL-4, IL-5, IL-13), type 1/2 (IL-2, IL-10), type 9 (IL-9), type 17/1 (IL-17A[F], GM-CSF, IL-21) and type 22 (IL-22) derived cytokines as well as the T-cell/antigen presentation cell derived factors Thymus and activation regulated chemokine (TARC), IL-27 and IP-10. Receiver operator characteristics (ROC) analysis showed that IL-5 was the strongest biomarker for nickel allergy. A broad spectrum of 33 cytokines and chemokines is involved in the allergen-specific immune response in nickel allergic patients. IL-5 remains, next to the lymphocyte proliferation test, the strongest biomarker for nickel allergy. Show less

The paraventricular nucleus of the hypothalamus (PVH) is a heterogeneous collection of neurons that play important roles in modulating feeding and energy expenditure. Abnormal development or ablation of the PVH results in hyperphagic obesity and defects in energy expenditure whereas selective activation of defined PVH neuronal populations can suppress feeding and may promote energy expenditure. Here, we characterize the contribution of calcitonin receptor-expressing PVH neurons (CalcRPVH) to energy balance control. We used Cre-dependent viral tools delivered stereotaxically to the PVH of CalcR2Acre mice to activate, silence, and trace CalcRPVH neurons and determine their contribution to body weight regulation. Immunohistochemistry of fluorescently-labeled CalcRPVH neurons demonstrates that CalcRPVH neurons are largely distinct from several PVH neuronal populations involved in energy homeostasis; these neurons project to regions of the hindbrain that are implicated in energy balance control, including the nucleus of the solitary tract and the parabrachial nucleus. Acute activation of CalcRPVH neurons suppresses feeding without appreciably augmenting energy expenditure, whereas their silencing leads to obesity that may be due in part due to loss of PVH melanocortin-4 receptor signaling. These data show that CalcRPVH neurons are an essential component of energy balance neurocircuitry and their function is important for body weight maintenance. A thorough understanding of the mechanisms by which CalcRPVH neurons modulate energy balance might identify novel therapeutic targets for the treatment and prevention of obesity. Show less

The melanocortin receptors (MC1R-MC5R) belong to class A G-protein-coupled receptors (GPCRs) and are known to have receptor-specific roles in normal and diseased states. Selectivity for MC4R is of particular interest due to its involvement in various metabolic disorders, including obesity, feeding regulation, and sexual dysfunctions. To further improve the potency and selectivity of MC4R (ant)agonist peptide ligands, we designed and synthesized a series of cyclic peptides based on the recent crystal structure of MC4R in complex with the well-characterized antagonist Show less

Morbid obesity represents the most severe form of obesity and surgical intervention would be its only successful treatment. Bariatric surgery could generate modifications in carbohydrate metabolism and in lipid profile plus lipoprotein-associated proteins and enzymes, such as lipoprotein-associated phoslipase A Thirty-seven patients with morbid obesity were recruited. Evaluations were performed before (T0) and 1 (T1) and 6 (T2) months after surgery. Glucose, insulin, high-sensitivity C-reactive protein (hsCRP), triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol, apolipoproteins (apo) A-I, and B plus Interleukin 1β and 6 levels in addition to CETP, Lp-PLA2, and PON 1 activities were determined. Body mass index decreased at T1 and T2 (p < 0.01). An improvement in all markers of insulin resistance (p < 0.05) was observed at T1. hsCRP levels diminished at T2 (p < 0.05). Triglyceride levels decreased at T1 and T2 (p < 0.05). HDL-C and apo A-I showed a decrease at T1 which was completely reversed at T2 (p < 0.05). Lp-PLA These results would be indicative of a favorable effect of bariatric surgery on markers of carbohydrate metabolism and cardiovascular disease lipid risk factors. Show less

Understanding the neural components modulating feeding-related behavior and energy expenditure is crucial to combating obesity and its comorbidities. Neurons within the paraventricular nucleus of the hypothalamus (PVH) are a key component of the satiety response; activation of the PVH decreases feeding and increases energy expenditure, thereby promoting negative energy balance. In contrast, PVH ablation or silencing in both rodents and humans leads to substantial obesity. Recent studies have identified genetically-defined PVH subpopulations that control discrete aspects of energy balance (e.g. oxytocin (OXT), neuronal nitric oxide synthase 1 (NOS1), melanocortin 4-receptor (MC4R), prodynorphin (PDYN)). We previously demonstrated that non-OXT NOS1 Show less

Central leptin administration can ameliorate hyperglycemia in insulin-deficient rodent models independently of insulin; however, the underlying neuronal mechanism are unclear. Here, we investigate the contribution of key elements within the central melanocortin system by examining whether central leptin injection can ameliorate hyperglycemia in total insulin-deficient mice that either lacked melanocortin 4 receptors (MC4Rs) in the whole body [knockout (KO); MC4R KO] or selectively, in single-minded homolog 1 (SIM1)-expressing neurons (SIM1ΔMC4R). We further investigated the contribution of leptin receptors (LEPRs) in agouti-related protein (AgRP)-expressing neurons (AgRP∆LEPR). Leptin injections into the cerebral ventricle attenuated mortality and elevated blood glucose in total insulin-deficient MC4R KO mice. Total insulin-deficient SIM1ΔMC4R mice exhibited the same magnitude reduction of blood glucose in response to leptin injections as MC4R KO mice, suggesting SIM1 neurons are key to MC4R-mediated, insulin-independent, glucose-lowering effects of leptin. Central leptin injection also partially rescued glucose levels in total insulin-deficient AgRP∆LEPR mice. In brain slice studies, basal discharge of AgRP neurons from mice with total insulin deficiency was increased and leptin partially reduced their firing rate without membrane potential hyperpolarization. Collectively, our findings indicate that, contrary to glucose-lowering effects of leptin in the presence of insulin or partial insulin deficiency, MC4Rs in SIM1 neurons and LEPRs in AgRP neurons are not solely responsible for glucose-lowering effects of leptin in total insulin deficiency. This indicates that the central melanocortin system operates with other neuronal systems to fully mediate glucose-lowering effects of leptin in an insulin-independent manner. Show less

The cholesterol-ester transfer protein (CETP) exchanges lipids between high-density lipoproteins (HDLs) and low-density lipoproteins (LDLs). The excessive transport of lipids from HDLs to LDLs mediated by this protein can cause an alteration in the deposition of lipoproteins onto the arterial walls, thus promoting the development of arteriosclerosis. Different CETP inhibitors have been tested in recent years, but none has been confirmed as being effectively palliative for the disease. We employed in silico databases and molecular docking as a computational method to predict how potential CETP inhibitors could interact with the active site of the CETP protein. Upon previously comparing two computer software packages to determine which generated a greater number of accurate CETP-inhibitor-complex structures, we chose the more appropriate program for our studies. We then abstracted a series of databases of known CETP inhibitors and noninhibitors exhibiting different 50% concentrations of CETP-inhibitory (INH) activity, to generate virtual structures for docking with different combinations of the CETP receptor. From this process, we obtained as the most suitable structure 4F2A₁OB_C_PCW-it accordingly having a greater area under the receiver operating characteristic curve. The molecular docking of known compounds in comparison with the respective conformation of this inhibitor enabled us to obtain ΔGs (in kcal/mol) from which data we made a first exploration of unknown compounds for CETP-INH activity. Thus, the 4F2A₁OB_C_PCW structure was docked with DrugBank-Approved commercial compounds in an extensive database, whose status had already been established from pharmacokinetics and toxicology. In this study, we present a group of potential compounds as CETP-inhibitor candidates. Show less

The presence of H3K9me3 and heterochromatin protein 1 (HP1) are hallmarks of heterochromatin conserved in eukaryotes. The spreading and maintenance of H3K9me3 is effected by the functional interplay between the H3K9me3-specific histone methyltransferase Suv39h1 and HP1. This interplay is complex in mammals because the three HP1 isoforms, HP1α, β, and γ, are thought to play a redundant role in Suv39h1-dependent deposition of H3K9me3 in pericentric heterochromatin (PCH). Here, we demonstrate that despite this redundancy, HP1α and, to a lesser extent, HP1γ have a closer functional link to Suv39h1, compared to HP1β. HP1α and γ preferentially interact in vivo with Suv39h1, regulate its dynamics in heterochromatin, and increase Suv39h1 protein stability through an inhibition of MDM2-dependent Suv39h1-K87 polyubiquitination. The reverse is also observed, where Suv39h1 increases HP1α stability compared HP1β and γ. The interplay between Suv39h1 and HP1 isoforms appears to be relevant under genotoxic stress. Specifically, loss of HP1α and γ isoforms inhibits the upregulation of Suv39h1 and H3K9me3 that is observed under stress conditions. Reciprocally, Suv39h1 deficiency abrogates stress-dependent upregulation of HP1α and γ, and enhances HP1β levels. Our work defines a specific role for HP1 isoforms in regulating Suv39h1 function under stress via a feedback mechanism that likely regulates heterochromatin formation. Show less

Glucagon-like peptide-1 (GLP-1) receptor (GLP-1R), glucagon (GCG) receptor (GCGR), and glucose-dependent insulinotropic polypeptide (GIP, also known as gastric inhibitory polypeptide) receptor (GIPR), are three metabolically related peptide hormone receptors. A novel approach to the generation of multifunctional antibody agonists that activate these receptors has been developed. Native or engineered peptide agonists for GLP-1R, GCGR, and GIPR were fused to the N-terminus of the heavy chain or light chain of an antibody, either alone or in pairwise combinations. The fusion proteins have similar in vitro biological activities on the cognate receptors as the corresponding peptides, but circa 100-fold longer plasma half-lives. The GLP-1R mono agonist and GLP-1R/GCGR dual agonist antibodies both exhibit potent effects on glucose control and body weight reduction in mice, with the dual agonist antibody showing enhanced activity in the latter. Show less

A large number of genetic loci are associated with adult body mass index. However, the genetics of childhood body mass index are largely unknown. We performed a meta-analysis of genome-wide association studies of childhood body mass index, using sex- and age-adjusted standard deviation scores. We included 35 668 children from 20 studies in the discovery phase and 11 873 children from 13 studies in the replication phase. In total, 15 loci reached genome-wide significance (P-value < 5 × 10(-8)) in the joint discovery and replication analysis, of which 12 are previously identified loci in or close to ADCY3, GNPDA2, TMEM18, SEC16B, FAIM2, FTO, TFAP2B, TNNI3K, MC4R, GPR61, LMX1B and OLFM4 associated with adult body mass index or childhood obesity. We identified three novel loci: rs13253111 near ELP3, rs8092503 near RAB27B and rs13387838 near ADAM23. Per additional risk allele, body mass index increased 0.04 Standard Deviation Score (SDS) [Standard Error (SE) 0.007], 0.05 SDS (SE 0.008) and 0.14 SDS (SE 0.025), for rs13253111, rs8092503 and rs13387838, respectively. A genetic risk score combining all 15 SNPs showed that each additional average risk allele was associated with a 0.073 SDS (SE 0.011, P-value = 3.12 × 10(-10)) increase in childhood body mass index in a population of 1955 children. This risk score explained 2% of the variance in childhood body mass index. This study highlights the shared genetic background between childhood and adult body mass index and adds three novel loci. These loci likely represent age-related differences in strength of the associations with body mass index. Show less

The nuclear hormone receptors liver X receptor α (LXRα) and peroxisome proliferator-activated receptor γ (PPARγ) play key roles in the development of fatty liver. To determine the link between hepatic PPARγ and LXRα signaling and the development of fatty liver, a LXRα-specific ligand, T0901317, was administered to normal OB/OB and genetically obese (ob/ob) mice lacking hepatic PPARγ (Pparγ(ΔH)). In ob/ob-Pparγ(ΔH) and OB/OB-Pparγ(ΔH) mice, as well as ob/ob-Pparγ(WT) and OB/OB-Pparγ(WT) mice, the liver weights and hepatic triglyceride levels were markedly increased in response to T0901317 treatment. These results suggest that hepatic PPARγ and LXRα signals independently contribute to the development of fatty liver. Show less

Aneuploidy, a chromosome content that is not a multiple of the haploid karyotype, is associated with reduced fitness in all organisms analyzed to date. In budding yeast aneuploidy causes cell proliferation defects, with many different aneuploid strains exhibiting a delay in G1, a cell cycle stage governed by extracellular cues, growth rate, and cell cycle events. Here we characterize this G1 delay. We show that 10 of 14 aneuploid yeast strains exhibit a growth defect during G1. Furthermore, 10 of 14 aneuploid strains display a cell cycle entry delay that correlates with the size of the additional chromosome. This cell cycle entry delay is due to a delayed accumulation of G1 cyclins that can be suppressed by supplying cells with high levels of a G1 cyclin. Our results indicate that aneuploidy frequently interferes with the ability of cells to grow and, as with many other cellular stresses, entry into the cell cycle. Show less