Persistence of hepatitis B virus (HBV) covalently closed circular DNA (cccDNA) under current antiviral therapy is a major barrier to eradication of chronic hepatitis B (CHB). Curing CHB will require novel strategies for specific disruption of cccDNA. The clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system is a newly developed tool for site-specific cleavage of DNA targets directed by a synthetic guide RNA (gRNA) base-paired to the target DNA sequence. To examine whether this system can cleave HBV genomes, we designed eight gRNAs against HBV of genotype A. With the HBV-specific gRNAs, the CRISPR/Cas9 system significantly reduced the production of HBV core and surface proteins in Huh-7 cells transfected with an HBV-expression vector. Among eight screened gRNAs, two effective ones were identified. Interestingly, one gRNA targeting the conserved HBV sequence acted against different genotypes. Using a hydrodynamics-HBV persistence mouse model, we further demonstrated that this system could cleave the intrahepatic HBV genome-containing plasmid and facilitate its clearance in vivo, resulting in reduction of serum surface antigen levels. These data suggest that the CRISPR/Cas9 system could disrupt the HBV-expressing templates both in vitro and in vivo, indicating its potential in eradicating persistent HBV infection.

Diabetic myopathy, a less studied complication of diabetes, exhibits the clinical observations characterized by a less muscle mass, muscle weakness and a reduced physical functional capacity. Accumulation of advanced glycation end-products (AGEs), known to play a role in diabetic complications, has been identified in ageing human skeletal muscles. However, the role of AGEs in diabetic myopathy remains unclear. Here, we investigated the effects of AGEs on myogenic differentiation and muscle atrophy in vivo and in vitro. We also evaluated the therapeutic potential of alagebrium chloride (Ala-Cl), an inhibitor of AGEs. Muscle fibre atrophy and immunoreactivity for AGEs, Atrogin-1 (a muscle atrophy marker) and phosphorylated AMP-activated protein kinase (AMPK) expressions were markedly increased in human skeletal muscles from patients with diabetes as compared with control subjects. Moreover, in diabetic mice we found increased blood AGEs, less muscle mass, lower muscular endurance, atrophic muscle size and poor regenerative capacity, and increased levels of muscle AGE and receptor for AGE (RAGE), Atrogin-1 and phosphorylated AMPK, which could be significantly ameliorated by Ala-Cl. Furthermore, in vitro, AGEs (in a dose-dependent manner) reduced myotube diameters (myotube atrophy) and induced Atrogin-1 protein expression in myotubes differentiated from both mouse myoblasts and primary human skeletal muscle-derived progenitor cells. AGEs exerted a negative regulation of myogenesis of mouse and human myoblasts. Ala-Cl significantly inhibited the effects of AGEs on myotube atrophy and myogenesis. We further demonstrated that AGEs induced muscle atrophy/myogenesis impairment via a RAGE-mediated AMPK-down-regulation of the Akt signalling pathway. Our findings support that AGEs play an important role in diabetic myopathy, and that an inhibitor of AGEs may offer a therapeutic strategy for managing the dysfunction of muscle due to diabetes or ageing.

Recessive mutations in the SLC26A4 gene are a common cause of hereditary hearing impairment worldwide. Previous studies have demonstrated that different SLC26A4 mutations may have different pathogenetic mechanisms. In the present study, we established a knock-in mouse model (i.e., Slc26a4tm1Dontuh/tm1Dontuh mice) homozygous for the c.919-2A>G mutation, which is a common mutation in East Asians. Mice were then subjected to audiologic assessment, a battery of vestibular evaluations, and inner ear morphological studies. All Slc26a4tm1Dontuh/tm1Dontuh mice revealed profound hearing loss, whereas 46% mice demonstrated pronounced head tilting and circling behaviors. There was a significant difference in the vestibular performance between wild-type and Slc26a4tm1Dontuh/tm1Dontuh mice, especially those exhibiting circling behavior. Inner ear morphological examination of Slc26a4tm1Dontuh/tm1Dontuh mice revealed an enlarged endolymphatic duct, vestibular aqueduct and sac, atrophy of stria vascularis, deformity of otoconia in the vestibular organs, consistent degeneration of cochlear hair cells, and variable degeneration of vestibular hair cells. Audiologic and inner ear morphological features of Slc26a4tm1Dontuh/tm1Dontuh mice were reminiscent of those observed in humans. These features were also similar to those previously reported in both knock-out Slc26a4−/− mice and Slc26a4loop/loop mice with the Slc26a4 p.S408F mutation, albeit the severity of vestibular hair cell degeneration appeared different among the three mouse strains.

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Aging and diabetes are known to be the major cause to affect the progression of osteoarthritis (OA). Advanced glycation end products (AGEs) have been observed to accumulate in various organs especially in joint tissue and do damage to the joint tissue during aging and diabetes. Synovial angiogenesis and inflammation are observed across the full range of OA severity. The signaling pathway of AGEs on vascular endothelial growth factor (VEGF) production and inflammatory responses in synoviocytes are still unclear. Here, we investigated the role of receptor for AGEs (RAGE) and the signaling pathway involved in AGEs-induced VEGF production and inflammatory responses in human synoviocytes. Human synoviocytes were cultured and treated with AGEs(25-100 mg/ml). AGEs significantly induced the protein expressions of cyclooxygenase-2 (COX-2) and VEGF and the productions of prostaglandin-E2 (PGE2), VEGF, interleukin-6 (IL-6), and metalloproteinase-13 (MMP-13) in human synoviocytes in a dose-dependent manner. Moreover, AGEs markedly activated the phosphorylations of IkB kinase (IKK)a/b, IkBa, and nuclear factor (NF)-kB-p65 proteins in human synoviocytes in a time-dependent manner. Treatment with neutralizing antibody for RAGE statistically significantly decreased the AGEs-induced increase in COX-2, VEGF, PGE2, IL-6, and MMP13 and AGEs-activated NF-kB pathway activation. Taken together, these findings indicate that AGEs are capable of inducing VEGF production and inflammatory responses via RAGE-NF-kB pathway activation in human synoviocytes. ß

We attempt to characterize the degree of skin thermal damage by using multiphoton microscopy to characterize dermal thermal damage. Our results show that dermal collagen and elastic fibers display different susceptibility to thermal injury. Morphologically, dermal collagen starts to denature at 60 degrees C while fracture and aggregation of elastic fibers do not occur until 65 degrees C. With increasing temperatures, the structures of both elastic and collagen fibers deteriorate. While second-harmonic-generation (SHG) imaging is helpful in identifying the denaturation temperature of collagen, autofluorescence (AF) imaging can help to identify the structural alternations of tissue at higher temperatures when SHG signals have decayed. We also employ a ratiometric approach based on the AF-to-SHG index of dermis (ASID) to characterize the degree of dermal thermal damage. Use of the ASID index can bypass the difficulty in analyzing inhomogeneous dermal fibers and show that dermal collagen starts to denature at 60 degrees C. Our results suggest that with additional developments, multiphoton microscopy has potential to be developed into an effective in vivo imaging technique to monitor and characterize dermal thermal damage.

Mutations in the SLC26A4 gene are a common cause of human hereditary hearing impairment worldwide. Previous studies have demonstrated that different SLC26A4 mutations have different pathogenetic mechanisms. By using a genotype-driven approach, we established a knock-in mouse model (i.e., Slc26a4tm2Dontuh/tm2Dontuh mice) homozygous for the common p.H723R mutation in the East Asian population. To verify the pathogenicity of the p.H723R allele in mice, we further generated mice with compound heterozygous mutations (i.e., Slc26a4tm1Dontuh/tm2Dontuh) by intercrossing Slc26a4+/tm2Dontuh mice with Slc26a4tm1Dontuh/tm1Dontuh mice, which segregated the c.919-2A>G mutation with an abolished Slc26a4 function. Mice were then subjected to audiologic assessments, a battery of vestibular evaluations, inner ear morphological studies, and noise exposure experiments. The results were unexpected; both Slc26a4tm2Dontuh/tm2Dontuh and Slc26a4tm1Dontuh/tm2Dontuh mice showed normal audiovestibular phenotypes and inner ear morphology, and they did not show significantly higher shifts in hearing thresholds after noise exposure than the wild-type mice. The results indicated not only the p.H723R allele was non-pathogenic in mice, but also a single p.H723R allele was sufficient to maintain normal inner ear physiology in heterozygous compound mice. There might be discrepancies in the pathogenicity of specific SLC26A4 mutations in humans and mice; therefore, precautions should be taken when extrapolating the results of animal studies to humans.

Background Male clients of female sex workers (FSWs) serve as a potential bridge of HIV to the general population. Little is known about the characteristics and risk factors for HIV infection among male clients patronizing FSWs in Hekou County, Yunnan Province in southern China bordering with Vietnam. Methods Male clients were recruited through outreach of study staff, referrals by Vietnamese FSWs, their bosses, and snowball sampling. Each participant completed a questionnaire survey and donated a blood specimen to test for HIV, herpes simplex virus type 2 (HSV-2), and syphilis. Logistic regression models were fitted to identify factors associated with HIV infection. Results Among 306 participants, 28 (9.2%) were HIV positive, 81 (26.5%) were HSV-2 positive, and none were infected with syphilis. Approximately half (n=149, 49.2%) reported always using condoms with sex workers in the past year; 36 (11.8%) reported a history of injection drug use (IDU). Compared to HIV negative men, HIV positive men were more likely to have a history of IDU (64.3% vs. 6.5%) and be co-infected with HSV-2 (50.0% vs. 24.1%). Conclusions IDU was the most salient risk factor for HIV infection in this study, which suggests that male clients may acquire HIV from routes other than commercial sex, but the significance of HSV-2 infection indicates that sexual transmission is also of concern. HIV prevention intervention programs for this often ignored and hard-to-reach risk group should be two-pronged, addressing both drug use and commercial sex.