METTL14 is decreased and regulates m6 A modification of α-synuclein in Parkinson's disease.

N6-methyladenosine (m6A), an emerging modification of messenger RNA, has been implicated in many biological processes. However, its role in Parkinson's disease (PD) remains largely unknown. Here, we investigated the role of m6A modification and its underlying mechanism in PD. First, 86 individuals with PD and 86 healthy controls were recruited from a pilot multicenter cohort. Levels of m6A and its modulators in peripheral blood mononuclear cells of patients with PD and controls were measured using an m6A RNA methylation quantification kit and quantitative real-time PCR. The underlying mechanism of m6A modification in PD was investigated in vitro through RNA immunoprecipitation assay, RNA stability assay, gene silencing or overexpression, western blot, and confocal immunoassay. The results show that mRNA levels of m6A, METTL3, METTL14, and YTHDF2 in patients with PD were significantly lower than in healthy controls, and METTL14 was the main factor involved in abnormal m6A modification. Area under the curve (AUC) analysis suggests METTL14 may provide excellent diagnostic capability for PD, especially when combined with plasma α-synuclein (α-syn). Spearman correlation analysis identified that METTL14 was moderately negatively correlated with plasma α-syn and the motor function of PD. Mechanistic experiments demonstrated that Mettl14 targets and regulates the expression of the α-syn gene using its methylation function. Overexpression of Mettl14 dramatically increased m6 A modification of α-syn mRNA and weakened its stability. Further results suggest that α-syn mRNA was modified by Mettl14 binding of an m6 A motif in the coding region of α-syn mRNA, while the reading protein Ythdf2 was involved in recognizing m6 A-modified α-syn mRNA. Taken together, our results reveal the potential of METTL14 as a novel diagnostic biomarker for PD and identify modification of pathogenic α-syn protein by METTL14 via an m6 A-YTHDF2-dependent mechanism.

The emerging role of circular RNAs in Parkinson's disease.

Parkinson's disease (PD) is the second most prevalent neurodegenerative disease and the most common movement disorder. It involves a gradual loss of dopaminergic neurons in the substantia nigra. Although many studies have been conducted, the underlying molecular pathways of PD remain largely unknown. Circular RNAs (circRNAs), a novel class of non-coding RNAs with a covalently closed loop structure, are common in the brain. They are stable, conserved molecules that are widely expressed in eukaryotes in tissue-, cell-, and development-specific patterns. Many circRNAs have recently been identified in nervous system diseases, and some circRNA expression profiles have been linked to PD. Given that recent research has indicated the essential roles of various circRNAs in the development and progression of neurodegenerative diseases, the identification of individual circRNAs may be a promising strategy for finding new treatment targets for PD. Moreover, the search for circRNAs with high specificity and sensitivity will open up new avenues for the early diagnosis and treatment of PD. Herein, we address the biogenesis, properties, and roles of circRNAs and review their potential utility as biomarkers and therapeutic targets in PD.

Decreased soluble Nogo-B in serum as a promising biomarker for Parkinson's disease.

Background: Recently, the neurite outgrowth inhibitor-B (Nogo-B) receptor has been reported as a novel candidate gene for Parkinson's disease (PD). Nogo-B receptors need to combine with soluble Nogo-B to exert their physiological function. However, little is known about the relationship between serum soluble Nogo-B and PD. Methods: Serum levels of sNogo-B and α-Synuclein (α-Syn) were measured in a cohort of 53 patients with PD and 49 healthy controls with the ELISA kit method. Results: Serum sNogo-B level is significantly lower in the PD group than that in healthy controls and is negatively correlated with UPDRS-III score (p = 0.049), H&Y stage (p = 0.0108) as well as serum α-Syn level (p = 0.0001). The area under the curve (AUC) of serum sNogo-B in differentiating patients with PD from controls was 0.801 while the AUC of serum α-Syn was 0.93. Combining serum sNogo-B and α-Syn in differentiating patients with PD from HC presented higher discriminatory potential (AUC = 0.9534). Conclusion: Decreased serum sNogo-B may be a potential biomarker for PD. Lower Nogo-B level reflects worse motor function and disease progression of PD. Serum sNogo-B is of added value to serum α-Syn panel in distinguishing PD from controls. Future studies are needed to confirm in larger samples and different populations.

The Potential Circular RNAs Biomarker Panel and Regulatory Networks of Parkinson's Disease.

Parkinson's disease (PD) is a progressive neurodegenerative disease. It has been reported that circular RNAs (circRNAs) play important roles in several neurological diseases. However, the role and regulatory networks of circRNAs in PD are still largely unclear. In this study, we first compared the global expression level of circRNAs from patients with PD and controls using microarray, then the candidate circRNAs were validated in another PD cohort. The possible functions of these candidate circRNAs were analyzed using Gene Ontology (GO) analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, and the regulatory networks of these candidate circRNAs were constructed through circRNA-miRNA-mRNA regulatory networks, protein-protein interaction (PPI) networks, and transcription factor-circRNA networks. The results indicated that hsa_circRNA_101275, hsa_circRNA_103730, and hsa_circRNA_038416 were significantly more highly expressed in patients with PD, while hsa_circRNA_102850 was lower expressed in patients with PD when compared with controls. A circRNA panel combining the four differentially expressed circRNA showed a high diagnostic ability to distinguish patients with PD from controls (AUC = 0.938). Furthermore, GO and KEGG analysis showed these candidate circRNAs were enriched in PI3K-Akt and MAPK signaling pathways. We established circRNA-miRNA-mRNA regulatory networks and identified 10 hub genes (ESR1, PTEN, SHC1, IGF1R, SMAD2, KRAS, MDM2, HIF1A, BMP4, and ACVR2B) were closely related to PD by using PPI network analysis. Besides, these circRNAs were predicted to be regulated through tyrosine hydroxylase (TH)-relevant transcription factors such as GATA2 and GATA3. In conclusion, our results suggest that the circRNA panel and the established circRNA-miRNA-mRNA regulation networks might provide potential novel biomarkers and therapeutic targets for PD.

The Chinese Parkinson's Disease Registry (CPDR): Study Design and Baseline Patient Characteristics.

BACKGROUND: There is a lack of large multicenter Parkinson's disease (PD) cohort studies and limited data on the natural history of PD in China. OBJECTIVES: The objective of this study was to launch the Chinese Parkinson's Disease Registry (CPDR) and to report its protocol, cross-sectional baseline data, and prospects for a comprehensive observational, longitudinal, multicenter study. METHODS: The CPDR recruited PD patients from 19 clinical sites across China between January 2018 and December 2020. Clinical data were collected prospectively using at least 17 core assessment scales. Patients were followed up for clinical outcomes through face-to-face interviews biennially. RESULTS: We launched the CPDR in China based on the Parkinson's Disease & Movement Disorders Multicenter Database and Collaborative Network (PD-MDCNC). A total of 3148 PD patients were enrolled comprising 1623 men (51.6%) and 1525 women (48.4%). The proportions of early-onset PD (EOPD, age at onset ≤50 years) and late-onset PD (LOPD) were 897 (28.5%) and 2251 (71.5%), respectively. Stratification by age at onset showed that EOPD manifested milder motor and nonmotor phenotypes and was related to increased probability of dyskinesia. Comparison across genders suggested a slightly older average age at PD onset, milder motor symptoms, and a higher rate of developing levodopa-induced dyskinesias in women. CONCLUSIONS: The CPDR is one of the largest multicenter, observational, longitudinal, and natural history studies of PD in China. It offers an opportunity to expand the understanding of clinical features, genetic, imaging, and biological markers of PD progression. © 2022 International Parkinson and Movement Disorder Society.

CRISPR-enhanced human adipocyte browning as cell therapy for metabolic disease.

Obesity and type 2 diabetes are associated with disturbances in insulin-regulated glucose and lipid fluxes and severe comorbidities including cardiovascular disease and steatohepatitis. Whole body metabolism is regulated by lipid-storing white adipocytes as well as "brown" and "brite/beige" adipocytes that express thermogenic uncoupling protein 1 (UCP1) and secrete factors favorable to metabolic health. Implantation of brown fat into obese mice improves glucose tolerance, but translation to humans has been stymied by low abundance of primary human beige adipocytes. Here we apply methods to greatly expand human adipocyte progenitors from small samples of human subcutaneous adipose tissue and then disrupt the thermogenic suppressor gene NRIP1 by CRISPR. Ribonucleoprotein consisting of Cas9 and sgRNA delivered ex vivo are fully degraded by the human cells following high efficiency NRIP1 depletion without detectable off-target editing. Implantation of such CRISPR-enhanced human or mouse brown-like adipocytes into high fat diet fed mice decreases adiposity and liver triglycerides while enhancing glucose tolerance compared to implantation with unmodified adipocytes. These findings advance a therapeutic strategy to improve metabolic homeostasis through CRISPR-based genetic enhancement of human adipocytes without exposing the recipient to immunogenic Cas9 or delivery vectors.

Multicenter analysis and a rapid screening model to predict early novel coronavirus pneumonia using a random forest algorithm.

ABSTRACT: Early determination of coronavirus disease 2019 (COVID-19) pneumonia from numerous suspected cases is critical for the early isolation and treatment of patients.The purpose of the study was to develop and validate a rapid screening model to predict early COVID-19 pneumonia from suspected cases using a random forest algorithm in China.A total of 914 initially suspected COVID-19 pneumonia in multiple centers were prospectively included. The computer-assisted embedding method was used to screen the variables. The random forest algorithm was adopted to build a rapid screening model based on the training set. The screening model was evaluated by the confusion matrix and receiver operating characteristic (ROC) analysis in the validation.The rapid screening model was set up based on 4 epidemiological features, 3 clinical manifestations, decreased white blood cell count and lymphocytes, and imaging changes on chest X-ray or computed tomography. The area under the ROC curve was 0.956, and the model had a sensitivity of 83.82% and a specificity of 89.57%. The confusion matrix revealed that the prospective screening model had an accuracy of 87.0% for predicting early COVID-19 pneumonia.Here, we developed and validated a rapid screening model that could predict early COVID-19 pneumonia with high sensitivity and specificity. The use of this model to screen for COVID-19 pneumonia have epidemiological and clinical significance.

Prevalence and Clinical Features of FOG in Chinese PD Patients, a Multicenter and Cross-Sectional Clinical Study.

Objectives: Freezing of gait (FOG) is generally considered as an independent symptom of Parkinson's disease (PD) with a complex pathophysiology. There is a wide range of associated clinical features of FOG reported from different studies without consistent conclusion. Thus, a multicenter, cross-sectional study was designed to investigate the prevalence and clinical features of FOG together with its unique contribution quality of life in Chinese PD patients. Methods: Eight hundred and thirty eight PD patients were consecutively recruited into this study from 12 hospital centers in six provinces in China. Clinical information, including motor and neuropsychological features as well as pharmacological details, was collected. Results: Of 827 PD patients, 245 (29.63%) reported FOG. The prevalence of FOG was strongly correlated with modified H-Y stages and symptomatic duration (p < 0.01). 84.90% freezers experienced FOG during turning and 88.98% experienced when initiating the first step. Compared with non-freezers, freezers reported longer disease duration (7.73 ± 5.44 vs. 4.69 ± 3.94, p < 0.000), higher frequent PIGD phenotype (61.22 vs. 35.91%, p < 0.000), higher scores of UPDRS III (32.85 ± 15.47 vs. 22.38 ± 12.89, p < 0.000), HAMA (10.99 ± 7.41 vs. 7.59 ± 6.47, p < 0.000), HAMD (15.29 ± 10.29 vs. 10.58 ± 8.97, p < 0.000) and lower MMSE score (25.12 ± 5.27 vs. 26.63 ± 3.97, p < 0.000), and higher daily levodopa dosage (432.65 ± 264.31 vs. 319.19 ± 229.15, p < 0.000) with less frequent initial use of dopaminergic agonist (8.57 vs. 14.78%, p < 0.05). Using binary logistic regression, the associated factors of FOG might be non-tremor dominant onset (OR = 3.817, p < 0.000), the presence of anxiety (OR = 2.048, p < 0.000) and imbalance (OR = 4.320, p = 0.012). Freezers had poorer quality of life than non-freezers and FOG impacted PDQ-8 independently. Conclusion: Nearly one third of the PD patients experienced FOG. Its frequency increased with PD progression and FOG reduced independently the quality of life. Non-tremor dominant, disease progression, and anxiety were risk factors of FOG.

A rapid screening model for early predicting novel coronavirus pneumonia in Zhejiang Province of China: a multicenter study.

Novel coronavirus pneumonia (NCP) has been widely spread in China and several other countries. Early finding of this pneumonia from huge numbers of suspects gives clinicians a big challenge. The aim of the study was to develop a rapid screening model for early predicting NCP in a Zhejiang population, as well as its utility in other areas. A total of 880 participants who were initially suspected of NCP from January 17 to February 19 were included. Potential predictors were selected via stepwise logistic regression analysis. The model was established based on epidemiological features, clinical manifestations, white blood cell count, and pulmonary imaging changes, with the area under receiver operating characteristic (AUROC) curve of 0.920. At a cut-off value of 1.0, the model could determine NCP with a sensitivity of 85% and a specificity of 82.3%. We further developed a simplified model by combining the geographical regions and rounding the coefficients, with the AUROC of 0.909, as well as a model without epidemiological factors with the AUROC of 0.859. The study demonstrated that the screening model was a helpful and cost-effective tool for early predicting NCP and had great clinical significance given the high activity of NCP.

Long-term outcomes in Chinese patients with chronic hepatitis B receiving nucleoside/nucleotide analogue therapy in real-world clinical practice: 5-year results from the EVOLVE study.

BACKGROUND: In China, the optimal management of individuals living with chronic HBV infection (CHB) remains an unmet need. The EVOLVE Study was a 5-year prospective, longitudinal, observational study that compared the clinical outcomes in treatment-naive CHB patients receiving entecavir (ETV) or lamivudine (LAM)-based therapies. METHODS: Males or females aged ≥18 years, diagnosed with CHB regardless of cirrhosis or hepatitis B e antigen (HBeAg) status were enrolled from tier 2 city hospitals (between 2012-2014). The choice of initial therapy and subsequent treatment modifications was at the discretion of treating physicians. Key outcomes included treatment modifications, virological response (HBV DNA <300 copies/ml) and HBV disease progression. RESULTS: Of the 3,408 patients enrolled, 1,807 and 628 received ETV and LAM-based therapy, respectively. The mean age was 39.5 years, 74% were male and 22.9% had cirrhosis. The rate of treatment modification was higher in the LAM-based versus ETV group (25.9% versus 13.7%); viral breakthrough was the most common reason in the LAM-based group versus financial reasons in the ETV group. At week 240, the virological response rate was 73% in both treatment groups. Compared with LAM-based therapy, ETV was associated with a significantly lower incidence of viral breakthrough (12.6% versus 2.1%) and genotypic resistance (10.1% versus 1.2%; P<0.0001 for both); significantly lower risk of HBV disease progression (14.0% versus 10.7%; P=0.0113); and lower rates of progression to decompensated cirrhosis (9.6% versus 6.4%) and hepatocellular carcinoma (1.9% versus 0.8%). CONCLUSIONS: This real-world, longitudinal study demonstrated a significantly lower risk of HBV-related disease progression, viral breakthrough and resistance with ETV versus LAM-based therapy. ClinicalTrials.gov NCT01726439.

In-flight transmission cluster of COVID-19: a retrospective case series.

BACKGROUND: No data is available about in-flight transmission of SARS-CoV-2. Here, we report an in-flight transmission cluster of COVID-19 and describe the clinical characteristics of these patients. METHODS: After a flight, laboratory-confirmed COVID-19 was reported in 12 patients. Ten patients were admitted to the designated hospital. Data was collected from 25th January to 28th February 2020. Clinical information was retrospectively collected. RESULTS: All patients were passengers, and none were flight attendants. The median age was 33 years, and 70% were females. None was admitted to intensive care unit, and no patients died up to 28th February. The median incubation period was 3.0 days and time from onset of illness to hospital admission was 2 days. The most common symptom was fever. Two patients were asymptomatic and had normal chest CT scan during hospital stay. On admission, initial RT-PCR was positive in 9 patients, and initial chest CT was positive in half of the patients. The median lung 'total severity score' of chest CT was 6. 'Crazy-paving' pattern, pleural effusion, and ground-glass nodules were seen. CONCLUSION: There is potential for COVID-19 transmission in aeroplanes, but the symptoms were mild in our patients. Passengers and attendants must be protected during flights.

Association of GLP-1 receptor gene polymorphisms with sporadic Parkinson's disease in Chinese Han population.

The Glucagon Like Peptide 1 Receptor (GLP1R) plays a critical role in selective death of dopaminergic neurons and development of Parkinson's disease (PD). However, little is known about genetic associations of GLP1R gene polymorphisms with PD susceptibility. Therefore, this study aimed to verify whether GLP1R polymorphisms contribute to PD risk in a Chinese Han population. We recruited 518 individuals comprising 259 sporadic PD patients and 259 healthy controls. All of the participants were genotyped for two possibly functional polymorphisms located in GLP1R (rs3765467 and rs6923761) using the Sequenom MassARRAY platform. The frequency of the rs3765467 GG genotype was significantly higher in the PD group compared with that in the control group (OR = 1.444, 95 % CI: 1.015-2.055, p =  0.041). Subgroup analysis revealed that male patients and late-onset patients with the rs3765467 GG genotype suffered an increased risk of PD compared with healthy controls (p =  0.021 and p =  0.012, respectively). However, the genotype and allele frequencies for rs6923761 were not significantly different between PD and healthy subjects. Our results indicate that the GLP1R rs3765467 GG genotype is a potential risk factor for PD, especially for male and late-onset PD patients in the Chinese Han population.

Association between long-term occupational manganese exposure and bone quality among retired workers.

Despite well documents for manganese-induced neurological deficits, limited researches are available for effects of manganese (Mn) exposure on the bone. Here we aimed to explore the associations between long-term occupational Mn exposure and bone quality among retired workers. We conducted a cross-sectional study of 304 exposed subjects (n, male = 161 and female = 143) and 277 control retired workers (n, male = 65 and female = 212) recruited from a ferromanganese refinery. Self-reported occupation types were used as exposure classification confirmed by expert consultation. Bone quality was measured by quantitative ultrasound (QUS). In sex-stratified analyses throughout, stiffness index (SI) and T-score levels of the participants in the highest exposed group [tertile 3 of Mn cumulative exposure index (Mn-CEI)] were significantly lower as compared with the control group among female workers (SI, mean, 61.60 vs. 68.17; T-score, mean, -3.01 vs. -2.34, both P < 0.05). In addition, SI and T-score were found to be negatively associated with Mn-CEI only in the highest exposure group as compared with the female controls (both P = 0.01). However, we did not find the significant difference for SI or T-score among the male subjects in exposure models and the male controls (P > 0.05). Our results suggest that female retired workers in the highest Mn-exposed model (tertile 3 of Mn-CEI) potentially experience a higher risk of developing osteoporosis compared with the female controls. Further investigations on possible mechanisms on bone quality alteration are needed in the future.

CRISPR-delivery particles targeting nuclear receptor-interacting protein 1 (Nrip1) in adipose cells to enhance energy expenditure.

RNA-guided, engineered nucleases derived from the prokaryotic adaptive immune system CRISPR-Cas represent a powerful platform for gene deletion and editing. When used as a therapeutic approach, direct delivery of Cas9 protein and single-guide RNA (sgRNA) could circumvent the safety issues associated with plasmid delivery and therefore represents an attractive tool for precision genome engineering. Gene deletion or editing in adipose tissue to enhance its energy expenditure, fatty acid oxidation, and secretion of bioactive factors through a "browning" process presents a potential therapeutic strategy to alleviate metabolic disease. Here, we developed "CRISPR-delivery particles," denoted CriPs, composed of nano-size complexes of Cas9 protein and sgRNA that are coated with an amphipathic peptide called Endo-Porter that mediates entry into cells. Efficient CRISPR-Cas9-mediated gene deletion of ectopically expressed GFP by CriPs was achieved in multiple cell types, including a macrophage cell line, primary macrophages, and primary pre-adipocytes. Significant GFP loss was also observed in peritoneal exudate cells with minimum systemic toxicity in GFP-expressing mice following intraperitoneal injection of CriPs containing Gfp-targeting sgRNA. Furthermore, disruption of a nuclear co-repressor of catabolism, the Nrip1 gene, in white adipocytes by CriPs enhanced adipocyte browning with a marked increase of uncoupling protein 1 (UCP1) expression. Of note, the CriP-mediated Nrip1 deletion did not produce detectable off-target effects. We conclude that CriPs offer an effective Cas9 and sgRNA delivery system for ablating targeted gene products in cultured cells and in vivo, providing a potential therapeutic strategy for metabolic disease.

Follow-up of the manganese-exposed workers healthy cohort (MEWHC) and biobank management from 2011 to 2017 in China.

BACKGROUND: Long-term excess exposure to environmental manganese (Mn) can lead to multi-system damage, especially in occupational populations. Therefore, we established a manganese-exposed workers healthy cohort (MEWHC), focusing on the systemic health effects related to Mn exposure. Here, we aimed to describe the follow-up activity for the MEWHC study and establish a standardized biological sample bank for the scientific management of high-quality biospecimens and the attached data from 2011 to 2017. METHODS: Baseline examinations for onsite workers were conducted, and the biobank for the MEWHC was first established in 2011; follow-up examinations occurred four times between July 2012 and November 2017. All questionnaires, clinical data and biological samples were routinely collected during each follow-up activity. Additional workers were recruited in 2016, which further enriched the resources of the biobank. RESULTS: A total of 2359 onsite workers and 612 retired workers at a ferromanganese refinery were enrolled in the prospective cohort, and their biological samples were obtained in the preliminary baseline survey and the follow-up investigation, including 2971 blood and urine samples from the cohort. In addition, 1524 hair samples, 1404 nail (toe and finger nails) and 1226 fecal samples were also collected. All specimens were preserved in the biobank, and the data were scientifically managed using a computer system. CONCLUSIONS: The MEWHC study in China provides an effective way to obtain biological samples such as plasma, DNA, hair and urine for storage in a biobank for further study. The standardized management of various samples is crucial for accessing high-quality biospecimens.

Hepatocyte-secreted DPP4 in obesity promotes adipose inflammation and insulin resistance.

Obesity-induced metabolic disease involves functional integration among several organs via circulating factors, but little is known about crosstalk between liver and visceral adipose tissue (VAT). In obesity, VAT becomes populated with inflammatory adipose tissue macrophages (ATMs). In obese humans, there is a close correlation between adipose tissue inflammation and insulin resistance, and in obese mice, blocking systemic or ATM inflammation improves insulin sensitivity. However, processes that promote pathological adipose tissue inflammation in obesity are incompletely understood. Here we show that obesity in mice stimulates hepatocytes to synthesize and secrete dipeptidyl peptidase 4 (DPP4), which acts with plasma factor Xa to inflame ATMs. Silencing expression of DPP4 in hepatocytes suppresses inflammation of VAT and insulin resistance; however, a similar effect is not seen with the orally administered DPP4 inhibitor sitagliptin. Inflammation and insulin resistance are also suppressed by silencing expression of caveolin-1 or PAR2 in ATMs; these proteins mediate the actions of DPP4 and factor Xa, respectively. Thus, hepatocyte DPP4 promotes VAT inflammation and insulin resistance in obesity, and targeting this pathway may have metabolic benefits that are distinct from those observed with oral DPP4 inhibitors.

Manganese in blood cells as an exposure biomarker in manganese-exposed workers healthy cohort.

Elevated exposure to manganese (Mn) has long been a public health concern. However, there is currently no consensus on the best exposure biomarker. Here we aimed to investigate the exposomic characteristics of plasma metals among Mn-exposed workers and explore the potential biomarkers of Mn exposure in the blood pool. First, total sixteen plasma metals (Calcium, Magnesium, Iron, Zinc, Copper, Selenium, Lead, Chromium, Arsenic, Manganese, Nickel, Molybdenum, Cadmium, Mercury, Thallium, and Cobalt) were determined among 40 occupationally Mn-exposed subjects. Second, Mn levels in both plasma and blood cells were detected among 234 workers from the manganese-exposed workers healthy cohort (MEWHC), respectively. Analysis of plasma metal exposome showed that the plasma Mn concentrations were positively correlated to plasma Fe (r=0.361), Ni (r=0.363), Cr (r=0.486), and Hg (r=0.313) (all p<0.05). Mn concentrations in plasma were not significantly correlated to external exposure levels (ptrend=0.200), and it was further confirmed among the 234 subjects (ptrend=0.452). However, Mn concentrations in blood cells progressively increased as the external exposure dose increased (low-exposure group vs high-exposure group, median 11.53µg/L vs 20.41µg/L, ptrend=0.001). Our results suggest that Mn in blood cells, but not plasma, could serve as a potential internal exposure biomarker. Larger validation studies are needed to establish the utility of this biomarker.

Decreasing CB1 receptor signaling in Kupffer cells improves insulin sensitivity in obese mice.

OBJECTIVE: Obesity-induced accumulation of ectopic fat in the liver is thought to contribute to the development of insulin resistance, and increased activity of hepatic CB1R has been shown to promote both processes. However, lipid accumulation in liver can be experimentally dissociated from insulin resistance under certain conditions, suggesting the involvement of additional mechanisms. Obesity is also associated with pro-inflammatory changes which, in turn, can promote insulin resistance. Kupffer cells (KCs), the liver's resident macrophages, are the major source of pro-inflammatory cytokines in the liver, such as TNF-α, which has been shown to inhibit insulin signaling in multiple cell types, including hepatocytes. Here, we sought to identify the role of CB1R in KCs in obesity-induced hepatic insulin resistance. METHODS: We used intravenously administered ß-D-glucan-encapsulated siRNA to knock-down CB1R gene expression selectively in KCs. RESULTS: We demonstrate that a robust knock-down of the expression of Cnr1, the gene encoding CB1R, results in improved glucose tolerance and insulin sensitivity in diet-induced obese mice, without affecting hepatic lipid content or body weight. Moreover, Cnr1 knock-down in KCs was associated with a shift from pro-inflammatory M1 to anti-inflammatory M2 cytokine profile and improved insulin signaling as reflected by increased insulin-induced Akt phosphorylation. CONCLUSION: These findings suggest that CB1R expressed in KCs plays a critical role in obesity-related hepatic insulin resistance via a pro-inflammatory mechanism.

Adipocyte lipid synthesis coupled to neuronal control of thermogenic programming.

BACKGROUND: The de novo biosynthesis of fatty acids (DNL) through fatty acid synthase (FASN) in adipocytes is exquisitely regulated by nutrients, hormones, fasting, and obesity in mice and humans. However, the functions of DNL in adipocyte biology and in the regulation of systemic glucose homeostasis are not fully understood. METHODS & RESULTS: Here we show adipocyte DNL controls crosstalk to localized sympathetic neurons that mediate expansion of beige/brite adipocytes within inguinal white adipose tissue (iWAT). Induced deletion of FASN in white and brown adipocytes of mature mice (iAdFASNKO mice) enhanced glucose tolerance, UCP1 expression, and cAMP signaling in iWAT. Consistent with induction of adipose sympathetic nerve activity, iAdFASNKO mice displayed markedly increased neuronal tyrosine hydroxylase (TH) and neuropeptide Y (NPY) content in iWAT. In contrast, brown adipose tissue (BAT) of iAdFASNKO mice showed no increase in TH or NPY, nor did FASN deletion selectively in brown adipocytes (UCP1-FASNKO mice) cause these effects in iWAT. CONCLUSIONS: These results demonstrate that downregulation of fatty acid synthesis via FASN depletion in white adipocytes of mature mice can stimulate neuronal signaling to control thermogenic programming in iWAT.

Developmental Role of Macrophage Cannabinoid-1 Receptor Signaling in Type 2 Diabetes.

Islet inflammation promotes ß-cell loss and type 2 diabetes (T2D), a process replicated in Zucker Diabetic Fatty (ZDF) rats in which ß-cell loss has been linked to cannabinoid-1 receptor (CB1R)-induced proinflammatory signaling in macrophages infiltrating pancreatic islets. Here, we analyzed CB1R signaling in macrophages and its developmental role in T2D. ZDF rats with global deletion of CB1R are protected from ß-cell loss, hyperglycemia, and nephropathy that are present in ZDF littermates. Adoptive transfer of CB1R-/- bone marrow to ZDF rats also prevents ß-cell loss and hyperglycemia but not nephropathy. ZDF islets contain elevated levels of CB1R, interleukin-1ß, tumor necrosis factor-α, the chemokine CCL2, and interferon regulatory factor-5 (IRF5), a marker of inflammatory macrophage polarization. In primary cultured rodent and human macrophages, CB1R activation increased Irf5 expression, whereas knockdown of Irf5 blunted CB1R-induced secretion of inflammatory cytokines without affecting CCL2 expression, which was p38MAPKα dependent. Macrophage-specific in vivo knockdown of Irf5 protected ZDF rats from ß-cell loss and hyperglycemia. Thus, IRF5 is a crucial downstream mediator of diabetogenic CB1R signaling in macrophages and a potential therapeutic target.