SIRT3 (Sirtuin-3) Prevents Ang II (Angiotensin II)-Induced Macrophage Metabolic Switch Improving Perivascular Adipose Tissue Function.

OBJECTIVE: Infiltrated macrophages actively promote perivascular adipose tissue remodeling and represent a dominant population in the perivascular adipose tissue microenvironment of hypertensive mice. However, the role of macrophages in initiating metabolic inflammation remains uncertain. SIRT3 (sirtuin-3), a NAD-dependent deacetylase, is sensitive to metabolic status and mediates adaptation responses. In this study, we investigated the role of SIRT3-mediated metabolic shift in regulating NLRP3 (Nod-like receptor family pyrin domain-containing 3) inflammasome activation. Approach and Results: Here, we report that Ang II (angiotensin II) accelerates perivascular adipose tissue inflammation and fibrosis, accompanied by NLRP3 inflammasome activation and IL (interleukin)-1ß secretion in myeloid SIRT3 knockout (SIRT3-/-) mice. This effect is associated with adipose tissue mitochondrial dysfunction. In vitro studies indicate that the deletion of SIRT3 in bone marrow-derived macrophages induces IL-1ß production by shifting the metabolic phenotype from oxidative phosphorylation to glycolysis. Mechanistically, SIRT3 deacetylates and activates PDHA1 (pyruvate dehydrogenase E1 alpha) at lysine 83, and the loss of SIRT3 leads to PDH activity decrease and lactate accumulation. Knocking down LDHA (lactate dehydrogenase A) or using carnosine, a buffer against lactic acid, attenuates IL-1ß secretion. Furthermore, the blockade of IL-1ß from macrophages into brown adipocytes restores thermogenic markers and mitochondrial oxygen consumption. Moreover, NLRP3 knockout (NLRP3-/-) mice exhibited reduced IL-1ß production while rescuing the mitochondrial function of brown adipocytes and alleviating perivascular adipose tissue fibrosis. CONCLUSIONS: SIRT3 represents a potential therapeutic target to attenuate NLRP3-related inflammation. Pharmacological targeting of glycolytic metabolism may represent an effective therapeutic approach.

High-Fat Diet-Induced Adipose Tissue and Liver Inflammation and Steatosis in Mice Are Reduced by Inhibiting Sialidases.

High-fat diet (HFD)-induced inflammation and steatosis of adipose tissue and liver are associated with a variety of serious health risks. Sialic acids are found as the distal terminal sugar on glycoproteins, which are removed by sialidases (neuraminidases). In humans and mice, pulmonary fibrosis is associated with up-regulation of sialidases, and injections of sialidase inhibitors attenuate bleomycin-induced pulmonary fibrosis. Sialidase levels are altered in obese rodents and humans. This report shows that for mice on an HFD, injections of the sialidase inhibitor N-acetyl-2,3-dehydro-2-deoxyneuraminic acid inhibit weight gain, reduce steatosis, and decrease adipose tissue and liver inflammation. Compared with control, mice lacking the sialidase neuraminidase 3 have reduced HFD-induced adipose tissue and liver inflammation. These data suggest that sialidases promote adipose and liver inflammation in response to a high-fat diet.

Celastrol attenuates inflammatory responses in adipose tissues and improves skeletal muscle mitochondrial functions in high fat diet-induced obese rats via upregulation of AMPK/SIRT1 signaling pathways.

Accumulating evidence indicates that adipose tissue inflammation and mitochondrial dysfunction in skeletal muscle are inextricably linked to obesity and insulin resistance. Celastrol, a bioactive compound derived from the root of Tripterygium wilfordii exhibits a number of attributive properties to attenuate metabolic dysfunction in various cellular and animal disease models. However, the underlying therapeutic mechanisms of celastrol in the obesogenic environment in vivo remain elusive. Therefore, the current study investigated the metabolic effects of celastrol on insulin sensitivity, inflammatory response in adipose tissue and mitochondrial functions in skeletal muscle of the high fat diet (HFD)-induced obese rats. Our study revealed that celastrol supplementation at 3 mg/kg/day for 8 weeks significantly reduced the final body weight and enhanced insulin sensitivity of the HFD-fed rats. Celastrol noticeably improved insulin-stimulated glucose uptake activity and increased expression of plasma membrane GLUT4 protein in skeletal muscle. Moreover, celastrol-treated HFD-fed rats showed attenuated inflammatory responses via decreased NF-κB activity and diminished mRNA expression responsible for classically activated macrophage (M1) polarization in adipose tissues. Significant improvement of muscle mitochondrial functions and enhanced antioxidant defense machinery via restoration of mitochondrial complexes I + III linked activity were effectively exhibited by celastrol treatment. Mechanistically, celastrol stimulated mitochondrial biogenesis attributed by upregulation of the adenosine monophosphate-activated protein kinase (AMPK) and sirtuin 1 (SIRT1) signaling pathways. Together, these results further demonstrate heretofore the conceivable therapeutic mechanisms of celastrol in vivo against HFD-induced obesity mediated through attenuation of inflammatory response in adipose tissue and enhanced mitochondrial functions in skeletal muscle.

Pancreatic panniculitis: the "bright" side of the moon in solid cancer patients.

BACKGROUND: Pancreatic panniculitis is a rare complication of pancreas disorders occurring in 0.3-3% of patients, most often accompanied by the pancreatic acinar carcinoma. It presents multiple, painful, deep, ill-defined, red-brown, migratory nodules and plaques of hard elastic consistency; often ulcerated and typically located on the lower proximal and distal extremities. The pathogenesis is not fully understood, but it is thought to result from lipolysis and fat necrosis with secondary tissue inflammation induced by pancreatic enzymes. Histopathology shows subcutaneous lobular fat necrosis with anuclear adipocytes (called ghost cells) surrounded by a mixed inflammatory infiltrate. Focal calcification may also be seen. The treatment is directed to the underlying disorder, which may result in regression of skin lesions. CASE PRESENTATION: We present two cases of pancreatic panniculitis with similar clinical, laboratory, and histopathological features associated with different internal malignancy. The first case, after extensive investigations showed the presence of a pancreatic carcinoma with multiple liver metastases and a poor prognosis. The second one instead is the first case in literature where painful subcutaneous nodules of the legs were the early manifestation of a neuroendocrine carcinoma of the adrenal gland. CONCLUSIONS: Although subcutaneous fat necrosis usually occurs late in the course of a malignancy, recognition of the association with pancreatic panniculitis may prevent a long delay in the diagnosis and management of the occult neoplasm. It should be primarily considered when panniculitis is widespread and persistent, and frequent relapses or tendency to ulcerate of the nodules are regarded as red flags.

From the Cover: Lung-Specific Overexpression of Constitutively Active IKK2 Induces Pulmonary and Systemic Inflammations but Not Hypothalamic Inflammation and Glucose Intolerance.

The lung is constantly exposed to ambient pollutants such as ambient fine particulate matter (PM2.5), making it one of the most frequent locations of inflammation in the body. Given the establishment of crucial role of inflammation in the pathogenesis of cardiometabolic diseases, pulmonary inflammation is thus widely believed to be an important risk factor for cardiometabolic diseases. However, the causality between them has not yet been well established. To determine if pulmonary inflammation is sufficient to cause adverse cardiometabolic effects, SFTPC-rtTA+/-tetO-cre+/-pROSA-inhibitor κB kinase 2(IKK2)ca+/- (LungIKK2ca) and littermate SFTPC-rtTA+/-tetO-cre-/-pROSA-IKK2ca+/- wildtype (WT) mice were fed with doxycycline diet to induce constitutively active Ikk2 (Ikk2ca) overexpression in the lung and their pulmonary, systemic, adipose, and hypothalamic inflammations, vascular function, and glucose homeostasis were assessed. Feeding with doxycycline diet resulted in IKK2ca overexpression in the lungs of LungIKK2ca but not WT mice. This induction of IKK2ca was accompanied by marked pulmonary inflammation as evidenced by significant increases in bronchoalveolar lavage fluid leukocytes, pulmonary macrophage infiltration, and pulmonary mRNA expression of tumor necrosis factor α (Tnfα) and interleukin-6 (Il-6). This pulmonary inflammation due to lung-specific overexpression of IKK2ca was sufficient to increase circulating TNFα and IL-6 levels, adipose expression of Tnfα and Il-6 mRNA, aortic endothelial dysfunction, and systemic insulin resistance. Unexpectedly, no significant alteration in hypothalamic expression of Tnfα and Il-6 mRNA and glucose intolerance were observed in these mice. Pulmonary inflammation is sufficient to induce systemic inflammation, endothelial dysfunction, and insulin resistance, but not hypothalamic inflammation and glucose intolerance.

Alpha-1 antitrypsin Pi*SZ genotype: estimated prevalence and number of SZ subjects worldwide.

The alpha-1 antitrypsin (AAT) haplotype Pi*S, when inherited along with the Pi*Z haplotype to form a Pi*SZ genotype, can be associated with pulmonary emphysema in regular smokers, and less frequently with liver disease, panniculitis, and systemic vasculitis in a small percentage of people, but this connection is less well established. Since the detection of cases can allow the application of preventive measures in patients and relatives with this congenital disorder, the objective of this study was to update the prevalence of the SZ genotype to achieve accurate estimates of the number of Pi*SZ subjects worldwide, based on studies performed according to the following criteria: 1) samples representative of the general population, 2) AAT phenotyping characterized by adequate methods, and 3) selection of studies with reliable results assessed with a coefficient of variation calculated from the sample size and 95% confidence intervals. Studies fulfilling these criteria were used to develop tables and maps with an inverse distance-weighted (IDW) interpolation method, to provide numerical and geographical information of the Pi*SZ distribution worldwide. A total of 262 cohorts from 71 countries were included in the analysis. With the data provided by these cohorts, a total of 1,490,816 Pi*SZ were estimated: 708,792 in Europe; 582,984 in America and Caribbean; 85,925 in Africa; 77,940 in Asia; and 35,176 in Australia and New Zealand. Remarkably, the IDW interpolation maps predicted the Pi*SZ prevalence throughout the entire world even in areas lacking real data. These results may be useful to plan strategies for future research, diagnosis, and management of affected individuals.

Adipocyte-Specific Deficiency of NADPH Oxidase 4 Delays the Onset of Insulin Resistance and Attenuates Adipose Tissue Inflammation in Obesity.

OBJECTIVE: Obesity is associated with insulin resistance and adipose tissue inflammation. Reactive oxygen species (ROS) increase in adipose tissue during the development of obesity. We previously showed that in response to excess nutrients like glucose and palmitate, adipocytes generated ROS via NADPH oxidase (NOX) 4, the major adipocyte isoform, instead of using mitochondrial oxidation. However, the role of NOX4-derived ROS in the development of whole body insulin resistance, adipocyte inflammation, and recruitment of macrophages to adipose tissue during the development of obesity is unknown. APPROACH AND RESULTS: In this study, control C57BL/6 mice and mice in which NOX4 has been deleted specifically in adipocytes were fed a high-fat, high-sucrose diet. During the development of obesity in control mice, adipocyte NOX4 and pentose phosphate pathway activity were transiently increased. Primary adipocytes differentiated from mice with adipocytes deficient in NOX4 showed resistance against high glucose or palmitate-induced adipocyte inflammation. Mice with adipocytes deficient in NOX4 showed a delayed onset of insulin resistance during the development of obesity, with an initial reduction in adipose tissue inflammation that normalized with prolonged high-fat, high-sucrose feeding. CONCLUSIONS: These findings imply that NOX4-derived ROS may play a role in the onset of insulin resistance and adipose tissue inflammation. As such, therapeutics targeting NOX4-mediated ROS production could be effective in preventing obesity-associated conditions, such as insulin resistance.

Characterization of Eicosanoids Produced by Adipocyte Lipolysis: IMPLICATION OF CYCLOOXYGENASE-2 IN ADIPOSE INFLAMMATION.

Excessive adipocyte lipolysis generates lipid mediators and triggers inflammation in adipose tissue. However, the specific roles of lipolysis-generated mediators in adipose inflammation remain to be elucidated. In the present study, cultured 3T3-L1 adipocytes were treated with isoproterenol to activate lipolysis and the fatty acyl lipidome of released lipids was determined by using LC-MS/MS. We observed that ß-adrenergic activation elevated levels of approximately fifty lipid species, including metabolites of cyclooxygenases, lipoxygenases, epoxygenases, and other sources. Moreover, we found that ß-adrenergic activation induced cyclooxygenase 2 (COX-2), not COX-1, expression in a manner that depended on activation of hormone-sensitive lipase (HSL) in cultured adipocytes and in the epididymal white adipose tissue (EWAT) of C57BL/6 mice. We found that lipolysis activates the JNK/NFκB signaling pathway and inhibition of the JNK/NFκB axis abrogated the lipolysis-stimulated COX-2 expression. In addition, pharmacological inhibition of COX-2 activity diminished levels of COX-2 metabolites during lipolytic activation. Inhibition of COX-2 abrogated the induction of CCL2/MCP-1 expression by ß-adrenergic activation and prevented recruitment of macrophage/monocyte to adipose tissue. Collectively, our data indicate that excessive adipocyte lipolysis activates the JNK/NFκB pathway leading to the up-regulation of COX-2 expression and recruitment of inflammatory macrophages.

Ablation of eNOS does not promote adipose tissue inflammation.

Adipose tissue (AT) inflammation is a hallmark characteristic of obesity and an important determinant of insulin resistance and cardiovascular disease; therefore, a better understanding of factors regulating AT inflammation is critical. It is well established that reduced vascular endothelial nitric oxide (NO) bioavailability promotes arterial inflammation; however, the role of NO in modulating inflammation in AT remains disputed. In the present study, 10-wk-old C57BL6 wild-type and endothelial nitric oxide synthase (eNOS) knockout male mice were randomized to either a control diet (10% kcal from fat) or a Western diet (44.9% kcal from fat, 17% sucrose, and 1% cholesterol) for 18 wk (n= 7 or 8/group). In wild-type mice, Western diet-induced obesity led to increased visceral white AT expression of inflammatory genes (e.g., MCP1, TNF-α, and CCL5 mRNAs) and markers of macrophage infiltration (e.g., CD68, ITGAM, EMR1, CD11C mRNAs, and Mac-2 protein), as well as reduced markers of mitochondrial content (e.g., OXPHOS complex I and IV protein). Unexpectedly, these effects of Western diet on visceral white AT were not accompanied by decreases in eNOS phosphorylation at Ser-1177 or increases in eNOS phosphorylation at Thr-495. Also counter to expectations, eNOS knockout mice, independent of the diet, were leaner and did not exhibit greater white or brown AT inflammation compared with wild-type mice. Collectively, these findings do not support the hypothesis that reduced NO production from eNOS contributes to obesity-related AT inflammation.

FADS2 genotype regulates delta-6 desaturase activity and inflammation in human adipose tissue.

Obesity is associated with disturbed lipid metabolism and low-grade inflammation in tissues. The aim of this study was to investigate the association between FA metabolism and adipose tissue (AT) inflammation in the Kuopio Obesity Surgery study. We investigated the association of surgery-induced weight loss and FA desaturase (FADS)1/2 genotypes with serum and AT FA profile and with AT inflammation, measured as interleukin (IL)-1ß and NFκB pathway gene expression, in order to find potential gene-environment interactions. We demonstrated an association between serum levels of saturated and polyunsaturated n-6 FAs, and estimated enzyme activities of FADS1/2 genes with IL-1ß expression in AT both at baseline and at follow-up. Variation in the FADS1/2 genes associated with IL-1ß and NFκB pathway gene expression in SAT after weight reduction, but not at baseline. In addition, the FA composition in subcutaneous and visceral fat correlated with serum FAs, and the associations between serum PUFAs and estimated D6D enzyme activity with AT inflammation were also replicated with corresponding AT FAs and AT inflammation. We conclude that the polymorphism in FADS1/2 genes associates with FA metabolism and AT inflammation, leading to an interaction between weight loss and FADS1/2 genes in the regulation of AT inflammation.

Neutrophilic panniculitis developing after treatment of metastatic melanoma with vemurafenib.

Vemurafenib is an inhibitor of BRAF and is used to treat patients with metastatic melanoma who carry a V600E BRAF mutation. Recently, four patients have been described in the literature who developed a neutrophilic panniculitis following treatment with a BRAF inhibitor. We present an additional case and review the clinical findings of the cases reported to date.

High expression of Dicer reveals a negative prognostic influence in certain subtypes of primary cutaneous T cell lymphomas.

BACKGROUND: Aberrant expression of microRNAs (miRNAs) has been implicated in oncogenesis of various tumors and primary cutaneous T cell lymphomas. Dicer, a ribonuclease III-like enzyme is essential for miRNA processing. OBJECTIVE: We initiated a retrospective study to characterize the alterations in the expression profile of Dicer in patients with primary cutaneous T cell lymphomas (CTCL). METHODS: A total of 50 consecutive patients with primary CTCL were studied, with the majority having mycosis fungoides (n=34). Five patients had primary cutaneous CD 30+ anaplastic large cell lymphoma, four patients each had lymphomatoid papulosis and primary cutaneous CD4-positive small/medium T-cell lymphoma, one primary cutaneous γδ T cell lymphoma, one Sézary syndrome and another subcutaneous panniculitis-like T cell lymphoma of αß-phenotype. Immunohistochemistry was performed on paraffin sections using a commercially available antibody against Dicer. Intensity of expression was correlated with clinical parameters including disease specific survival (DSS) and time to progression (TTP). RESULTS: After a median follow-up of 74 months (range: 1-271), 12/50 patients (24%) have died. Univariate and multivariate analysis for disease-specific survival showed Dicer expression and stage as a negative predictive factor in the sole group of MF patients (n=34) as well as in the heterogeneous group of patients (n=50), but not gender, histological subtype, primary localization of disease, age and recurrence of lymphoma (p>0.05). CONCLUSION: Our data suggest Dicer expression as a possible molecular marker in patients with MF and apparently indicate that miRNA(s) might be of clinical relevance in CTCL.

COX-2-mediated inflammation in fat is crucial for obesity-linked insulin resistance and fatty liver.

The aim was to examine the role of cyclooxygenase (COX)-2-mediated inflammation in the development of obese linked insulin resistance and fatty liver. The rats were fed separately regular diet (CONT), high-fat diet (HFD) ad libitum, or energy restrictedly for 12 weeks. Rats fed HFD ad libitum were further divided into three subgroups co-treated with vehicle (HFa), or a selective COX-2 inhibitor celecoxib (HFa-Cel) or mesulid (HFa-Mes). Euglycemic hyperinsulinemic clamp (EHC) experiment was performed at the end of study. Another set of rats with similar grouping was further divided into those with a 4, 8, or 12-week intervention period for hepatic sampling. Body weight was increased significantly and similarly in HFa, HFa-Cel, and HFa-Mes. Time-dependent increases in plasma insulin, glucose, 8-isoprostanes, leptin levels, homeostasis model assessment of insulin resistance (HOMA-IR) and hepatic triglyceride contents shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. During EHC period, the reduction in stimulation of whole body glucose uptake, suppression of hepatic glucose production and metabolic clearance rate of insulin shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. The enhanced COX-2 and tumor necrosis factor-alpha (TNF-alpha) but attenuated PPAR-gamma and C/EBP-alpha mRNA expressions in epididymal fat shown in HFa were significantly reversed in HFa-Cel and HFa-Mes. The increases in average cell size of adipocytes and CD68 positive cells shown in HFa were also significantly reversed in HFa-Cel and HFa-Mes. Our findings suggest that COX-2 activation in fat inflammation is important in the development of insulin resistance and fatty liver in high fat induced obese rats.

[Panniculitis associated with severe alpha 1-antitrypsin deficiency]. / Panniculitis associeret med svaer alfa-1-antitrypsinmangel.

Genetically determined deficiency of alpha-1-antitrypsin, the primary serum protease inhibitor, can result in pulmonary emphysema or liver cirrhosis, and panniculitis may be an early symptom. A case of recurring panniculitis in a 29 year-old woman is described, which led to the diagnosis of severe alpha-1-antitrypsin deficiency (Pi ZZ). Serum alpha-1-antitrypsin levels should be measured in patients presenting with panniculitis.

Alpha 1-antitrypsin deficiency-associated panniculitis: case report and review of the literature.

Alpha 1-antitrypsin is the primary serum proteinase inhibitor. Alpha 1-antitrypsin deficiency, especially the ZZ genotype, has been linked mainly to emphysema and cirrhosis; it is also associated with paniculitis. A case of alpha 1-AT-associated panniculitis was documented in a 13-year-old girl in whom a deficiency of the enzyme was known to be present from infancy. This is unusual, since alpha 1-AT panniculitis previously was described in older patients without prior knowledge of the duration of the deficiency. Our patient developed erythematous, subcutaneous nodules subsequent to trauma, which later developed into deep, painless ulcers. We report this case so that the condition may be suspected in patients with panniculitis. The diagnosis may be confirmed by measuring quantitative alpha 1-AT serum levels and by enzyme genotyping. The treatment of choice is dapsone.

Use of anti-collagenase properties of doxycycline in treatment of alpha 1-antitrypsin deficiency panniculitis.

Three patients (a 71-year-old man and 2 women, 73 and 50 years, respectively) with recurrent panniculitis associated with alpha 1-antitrypsin deficiency are presented. Because the concept of chronic and exaggerated inflammatory response in the patients with alpha 1-antitrypsin deficiency is based on the theory of protease-antiprotease imbalance, we suggest that tetracyclines will alleviate this condition. Indeed, tetracyclines were found to inhibit collagenase activity. The total remission of the condition in these 3 patients underlines for the first time the effects of doxycycline on a condition characterized by deficiency of the antiprotease system. A review of the 23 reported cases of panniculitis associated with alpha 1-antitrypsin deficiency is presented in table form.