Infection with hepatitis C virus (HCV) is still a major public health problem, and the events leading to hepatocyte infection are not yet fully understood. Combining confocal microscopy with biochemical analysis and studies of infection requirements using pharmacological inhibitors and small interfering RNAs, we show here that engagement of CD81 activates the Rho GTPase family members Rac, Rho, and Cdc42 and that the block of these signaling pathways drastically reduces HCV infectivity. Activation of Rho GTPases mediates actin-dependent relocalization of the HCV E2/CD81 complex to cell-cell contact areas where CD81 comes into contact with the tight-junction proteins occludin, ZO-1, and claudin-1, which was recently described as an HCV coreceptor. Finally, we show that CD81 engagement activates the Raf/MEK/ERK signaling cascade and that this pathway affects postentry events of the virus life cycle. In conclusion, we describe a range of cellular events that are manipulated by HCV to coordinate interactions with its multiple coreceptors and to establish productive infections and find that CD81 is a central regulator of these events.Hepatitis C virus (HCV), the causal agent of hepatitis C, is a positive-strand RNA virus that belongs to the Flaviviridae family (11). The genome encodes a single polyprotein that is processed by a combination of host and viral peptidases into at least 10 different structural and nonstructural proteins. The HCV envelope is formed by the two heavily N-glycosylated type I transmembrane proteins E1 and E2, which are present on the virus as heterodimers (44,48) anchored to a host cellderived double-layer lipid membrane.HCV infects mainly hepatocytes, but the precise mechanisms of early infection are largely unknown. As for other flaviviruses, it is generally accepted that HCV glycoproteins E1 and E2 play a major role in virus binding and entry into target cells (58).Several putative HCV receptors have been identified so far. Some of these, like the low-density lipoprotein (LDL) receptor (LDLR) (1) and other cell surface proteins involved in serum lipoprotein binding and metabolism, seem to act as relatively nonspecific attachment factors to allow virus concentration on the cell surface, as in the infected host, HCV can be associated with LDL and very low-density lipoprotein (VLDL). The tetraspanin molecule CD81 (49) and the scavenger receptor class B type I (SR-BI) (54) were both identified as putative receptors based on their interaction with recombinant soluble E2 (rE2) protein, and their role has been confirmed by means of HCV pseudotyped retroviral particles (2,14,29) and by the recently established in vitro infectious HCV system (HCVcc) (21,(30)(31)(32)59). In addition, CD81 has been shown to play a role in the infection of primary human hepatocytes by serumderived HCV (45). CD81 is an integral membrane protein that shows the structure common to all tetraspanins, with four transmembrane domains delimiting a large extracellular loop and a small extracellular loop and three short intracel...

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Tumor necrosis factor (TNF)-a is a pro-inflammatory cytokine associated with psoriasis pathogenesis. Anti-TNF-a therapies are effective in psoriasis. A significant weight gain has been reported in patients treated with anti-TNF-a agents. The aim of the present study was to evaluate the body composition changes in psoriatic patients receiving anti-TNF-a therapies according with disease phenotype. Forty patients affected with psoriasis were followed up for 24 weeks and divided into two groups: psoriasis vulgaris (PsO) and psoriatic arthritis (PsA). Anthropometric, blood biochemical, body composition parameters, resting metabolic rate, and disease activity indexes were measured at baseline and at week 24. After 24 weeks of anti-TNF-a administration, the disease activity indexes and concentration of inflammatory markers were significantly decreased. Seventy-five percent of PsO and 60% of PsA patients had an increase in body weight. Weight changes correlated with fat mass gain in the PsO group, and with fat and lean mass gain in the PsA group. In the present study, we demonstrated that a blockage of TNF-a bioactivity is related with fat and lean mass gain in both PsO and PsA subjects. The anti-TNF-a therapies could play a key role in the cross talk between adipose tissue and skeletal muscle, mediated by the reduction of TNF-a and interleukin-6 production.

The normal‐weight obese (NWO) syndrome was identified in women whose body weight (BW) and BMI are normal but whose fat mass (FM) is >30%. In these subjects, an early inflammatory status has been demonstrated. The aim was to verify whether oxidative stress occurs in NWO. Sixty age‐matched white Italian women were studied and subdivided as follows: 20 normal‐weight individuals (NW) (BMI <25 kg/m2; FM% <30%); 20 NWO (BMI <25 kg/m2; FM% >30%); 20 preobese‐obese (OB) (BMI >25 kg/m2; FM% >30%). Anthropometric, body composition (by dual‐energy X‐ray absorptiometry) variables, plasma levels of some cytokines, reduced glutathione (GSH), lipid hydroperoxide (LOOH), nitric oxide (NO) metabolites (NO2−/NO3−), antioxidant nonproteic capacity (ANPC) were measured and compared between groups. Glucose and lipid metabolism parameters were assessed. GSH and NO2−/NO3− levels resulted lower in OB and NWO compared to NW (P < 0.01). LOOH levels resulted higher in OB and NWO (P < 0.01). ANPC in NWO was lower than NW but higher with respect to OB (P < 0.01). Correlation analysis revealed strong associations between GSH levels and BW, BMI, FM% (R = −0.45, at least P < 0.05); waist circumference (W) (R = −0.33, P < 0.05); FFM% (R = 0.45, P < 0.01); IL‐1α, IL‐6, IL‐10, IL‐15 (R = −0.39, −0.33, −0.36 −0.34, respectively, P < 0.05); triglycerides (R = −0.416, P < 0.05). LOOH levels were negatively related to FFM% (R = −0.413, P < 0.05) and positively to FM%, IL‐15, TNF‐α, insulin, total cholesterol, low‐density lipoprotein cholesterol, and triglycerides (R = 0.408, R = 0.502, R = 0.341, R = 0.412, R = 0.4036, R = 0.405, R = 0.405, respectively, P < 0.05). The study clearly indicates that NWO, besides being in early inflammatory status, are contextually exposed to an oxidative stress related to metabolic abnormalities occurring in obesity.

Background and objectives:Relapsing remitting multiple sclerosis (RRMS), aquaporin4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) may have overlapping clinical features. There is an unmet need for imaging markers that differentiate between them when serologic testing is unavailable or ambiguous. We assessed whether imaging characteristics typical of MS discriminate RRMS from AQP4-NMOSD and MOGAD, alone and in combination.Methods:Adult, non-acute patients with RRMS, APQ4-NMOSD, MOGAD and healthy controls, were prospectively recruited at the National Hospital for Neurology and Neurosurgery (London, UK), and the Walton Centre (Liverpool, UK) between 2014 and 2019. They underwent conventional and advanced brain, cord and optic nerve MRI, and optical coherence tomography.Results:A total of 91 consecutive patients (31 RRMS, 30 APQ4-NMOSD, 30 MOGAD) and 34 healthy controls were recruited. The most accurate measures differentiating RRMS from AQP4-NMOSD were the proportion of lesions with the central vein sign (CVS) (84% vs. 33%, accuracy/specificity/sensitivity: 91/88/93%, p<0.001), followed by cortical lesions (median: 2 [range: 1-14] vs. 1 [0-1], accuracy/specificity/sensitivity: 84/90/77%, p=0.002), and white matter lesions (mean: 39.07 [±25.8] vs. 9.5 [±14], accuracy/specificity/sensitivity: 78/84/73%, p=0.001). The combination of higher proportion of CVS, cortical lesions and optic nerve magnetization transfer ratio reached the highest accuracy in distinguishing RRMS from AQP4-NMOSD (accuracy/specificity/sensitivity: 95/92/97%, p<0.001).The most accurate measures favouring RRMS over MOGAD were: white matter lesions (39.07 [±25.8] vs. 1 [±2.3], accuracy/specificity/sensitivity: 94/94/93%, p=0.006), followed by cortical lesions (2 [1-14] vs. 1 [0-1], accuracy/specificity/sensitivity: 84/97/71%, p=0.004), and retinal nerve fibre layer thickness (RNFL) (mean: 87.54 [±13.83] vs 75.54 [±20.33], accuracy/specificity/sensitivity: 80/79/81%, p=0.009). Higher cortical lesion number combined with higher RNFL thickness best differentiated RRMS from MOGAD (accuracy/specificity/sensitivity: 84/92/77%, p<0.001).Discussion:Cortical lesions, CVS and optic nerve markers achieve a high accuracy in distinguishing RRMS from APQ4-NMOSD and MOGAD. This information may be useful in clinical practice, especially outside the acute phase and when serologic testing is ambiguous or not promptly available.Classification of Evidence:This study provides Class II evidence that selected conventional and advanced brain, cord, and optic nerve MRI and OCT markers distinguish adult patients with RRMS from APQ4-NMOSD and MOGAD.