ALBERT

Description: Activation of hepatic stellate cells (HSCs) is the effector factor of hepatic fibrosis and hepatocellular carcinoma (HCC) development. Accumulating evidence suggests that retinoic acids (RAs), derivatives of vitamin A, contribute to prevention of liver fibrosis and carcinogenesis, however, regulatory mechanisms of RAs still remain exclusive. To elucidate RA signaling pathway, we previously performed a genome-wide screening of RA-responsive genes by in silico analysis of RA-response elements, and identified 26 RA-responsive genes. We found that thioredoxin interacting protein (TXNIP), which inhibits antioxidant activity of thioredoxin (TRX), was downregulated by all-trans retinoic acid (ATRA). In the present study, we demonstrate that ATRA ameliorates activation of HSCs through TXNIP suppression. HSC activation was attenuated by TXNIP downregulation, whereas potentiated by TXNIP upregulation, indicating that TXNIP plays a crucial role in activation of HSCs. Notably, we showed that TXNIP-mediated HSC activation was suppressed by antioxidant N-acetylcysteine. In addition, ATRA treatment or downregulation of TXNIP clearly declined oxidative stress levels in activated HSCs. These data suggest that ATRA plays a key role in inhibition of HSC activation via suppressing TXNIP expression, which reduces oxidative stress levels. This article is protected by copyright. All rights reserved

Description: ABSTRACT The potassium ion channel Kv3.1b is a member of a family of voltage-gated ion channels that are glycosylated in their mature form. In the present study, we demonstrate the impact of N-glycosylation at specific asparagine residues on the trafficking of the Kv3.1b protein. Large quantities of asparagine 229 (N229)-glycosylated Kv3.1b reached the plasma membrane, whereas N220-glycosylated and unglycosylated Kv3.1b were mainly retained in the endoplasmic reticulum (ER). These ER-retained Kv3.1b proteins were susceptible to degradation when co-expressed with calnexin, whereas Kv3.1b pools located at the plasma membrane were resistant. Mass spectrometry analysis revealed a complex type Hex 3 HexNAc 4 Fuc 1 glycan as the major glycan component of the N229-glycosylated Kv3.1b protein, as opposed to a high-mannose type Man 8 GlcNAc 2 glycan for N220-glycosylated Kv3.1b. Taken together, these results suggest that trafficking-dependent roles of the Kv3.1b potassium channel are dependent on N229 site-specific glycosylation and N-glycan structure, and operate through a mechanism whereby specific N-glycan structures regulate cell surface expression. This article is protected by copyright. All rights reserved

Description: Mesenchymal stem cell (MSC) has been well known to exert therapeutic potential for patients with myocardial infarction (MI). In addition, interleukin-10 (IL10) could attenuate MI through suppressing inflammation. Thus, the combination of MSC implantation with IL10 delivery may extend health benefits to ameliorate cardiac injury after MI. Here we established overexpression of IL10 in bone marrow-derived MSC through adenoviral transduction. Cell viability, apoptosis and IL10 secretion under ischemic challenge in vitro were examined. In addition, MSC was transplanted into the injured hearts in a rat model of MI. Four weeks after the MI induction, myocardial infarction, cardiac functions, apoptotic cells and inflammation cytokines were assessed. In response to in vitro oxygen-glucose deprivation (OGD), IL10 overexpression in MSC (Ad.IL10-MSC) enhanced cell viability, decreased apoptosis and increased IL10 secretion. Consistently, the implantation of Ad.IL10-MSCs into MI animals resulted in more reductions in myocardial infarct size, cardiac impairment and cell apoptosis, compared to the individual treatments of either MSC or IL10 administration. Moreover, the attenuation of both systemic and local inflammations was most prominent for Ad.IL10-MSC treatment. IL10 overexpression and MSC may exert a synergistic anti-inflammatory effect to alleviate cardiac injury after MI. This article is protected by copyright. All rights reserved

Description: Obesity is a condition likely associated with several dysmetabolic conditions or worsening of cardiovascular and other chronic disturbances. A key role in this mechanism seem to be played by the onset of low-grade systemic inflammation, highlighting the importance of the interplay between adipocytes and immune system cells. Adipocytes express a complex and highly adaptive biological profile being capable to selectively activate different metabolic pathways in order to respond to environmental stimuli. It has been demonstrated how adipocytes, under appropriate stimulation, can easily differentiate and de-differentiate thereby converting themselves into different phenotypes according to metabolic necessities. Although underlying mechanisms are not fully understood, growing in adipocyte size and the inability of storing triglycerides under overfeeding conditions seem to be crucial for the switching to a dysfunctional metabolic profile, which is characterized by inflammatory and apoptotic pathways activation and by the shifting to pro-inflammatory adipokines secretion. In obesity, changes in adipokines secretion along with adipocyte deregulation and fatty acids release into circulation contribute to maintain immune cells activation as well as their infiltration into regulatory organs. Over the well-established role of macrophages, recent findings suggest the involvement of new classes of immune cells such as T regulatory lymphocytes and neutrophils in the development inflammation and multi systemic worsening. Deeply understanding the pathways of adipocyte regulation and the de-differentiation process could be extremely useful for developing novel strategies aimed at curbing obesity-related inflammation and related metabolic disorders. This article is protected by copyright. All rights reserved

Description: Excessive inflammatory responses are critical in the pathogenesis of acute lung injury (ALI). Activating transcription factor 3 (ATF3) is a stress-induced transcriptional regulator that is a negative regulator of inflammatory responses. Therefore, we investigated the role and signaling pathways of ATF3 in lipopolysaccharide (LPS)-induced ALI in mice. The mouse macrophage RAW264.7 cells were cultured on HTS 24-Transwell filter plates in presence of ATF3 siRNA before exposure to LPS. ATF3 knock-out (KO) and wild type (WT) mice were challenged by intra-peritoneal injection of LPS (15mg/kg). Gene analysis was used to analyze differential gene expression between ATF3 KO and WT mice. LPS increased the expression of ATF3 in RAW264.7 cells and in lung tissues of mice, The concentration of TNFα and IL-6 was significantly increased in ATF3 siRNA-treated RAW264.7 cells compared to control cells after LPS stimulation. The concentration of TNFα, IL-6 and IL-1β in serum and lung tissue of ATF3 KO mice was significantly increased compared to ATF3 WT mice. In addition, the lung wet/dry weight and BALF protein were significantly increased in ATF3 KO mice after LPS injection at 6, 24 and 48-hours. The survival of ATF3 KO mice significantly decreased. Differential gene analysis showed that TL1A was highly expressed in LPS-induced lung tissues of ATF3 KO mice.Moreover, ATF3 down-regulated the expression of TL1A in RAW264.7 cells and in lung tissues. These findings suggest that ATF3 protects against LPS-induced ALI via inhibiting TL1A expression. This article is protected by copyright. All rights reserved

Description: Intestinal smooth muscle cells play a critical role in the remodeling of intestinal structure and functional adaptation after bowel resection. Recent studies have shown that supplementation of butyrate (Bu) contributes to the compensatory expansion of a muscular layer of the residual intestine in a rodent model of short-bowel syndrome (SBS). However, the underlying mechanism remains elusive. In this study, we found that the growth of human intestinal smooth muscle cells (HISMCs) was significantly stimulated by Bu via activation of Yes-Associated Protein (YAP). Incubation with 0.5 mM Bu induced a distinct proliferative effect on HISMCs, as indicated by the promotion of cell cycle progression and increased DNA replication. Notably, YAP silencing by RNA interference or its specific inhibitor significantly abolished the proliferative effect of Bu on HISMCs. Furthermore, Bu induced YAP expression and enhanced the translocation of YAP from the cytoplasm to the nucleus, which led to changes in the expression of mitogenesis genes, including TEAD1, TEAD4, CTGF and Cyr61. These results provide evidence that Bu stimulates the growth of human intestinal muscle cells by activation of YAP, which may be a potential treatment for improving intestinal adaptation. This article is protected by copyright. All rights reserved

Description: Zebrafish has become an excellent model for studying the development and function of inner ear. We report here a zebrafish line in which claudin 7b ( cldn7b ) locus is interrupted by a Tol2 transposon at its first intron. The homozygous mutants have enlarged otocysts, smaller or no otoliths, slowly formed semicircular canals, and insensitiveness to sound stimulation. These abnormal phenotypes and hearing loss of inner ear could be mostly rescued by injection of cldn7b -mRNA into one-cell stage homozygous mutant embryos. Mechanistically, cldn7b -deficiency interrupted the formation of apical junction complexes (AJCs) in otic epithelial cells of inner ear and the ion-homeostasis of endolymph, which then led to the loss of proper contact between otoliths and normally developed hair cells in utricle and saccule or aberrant mechanosensory transduction. Thus, Cldn7b is essential for the formation and proper function of inner ear through its unique role in keeping an initial integrity of otic epithelia during zebrafish embryogenesis. This article is protected by copyright. All rights reserved

Description: As a natural metabolite of limonoids from Dictamnus dasycarpus , fraxinellone has been reported to be neuroprotective and anti-inflammatory. However, its influence on cellular metabolism remains largely unknown. In the present study, we investigated the effect of fraxinellone on cellular senescence-induced by oxidative stress and the potential mechanism. We found that fraxinellone administration caused growth arrest and certainly repressed the activity of senescence associated β-galactosidase as well as the expression of senescence-associated-genes. Interestingly, this effect of fraxinellone is closely correlated with the restoration of impaired autophagy and the activation of AMPK. Notably, fraxinellone reacts in an AMPK-dependent but mTORC1-independent manner. Together, our study demonstrates for the first time that fraxinellone has the effect on senescence inhibition and AMPK activation, and supports the notion that autophagic mechanism is important for aging prevention. These findings expanded the list of natural compounds and will be potentially utilized for aging decay and/or AMPK activation. This article is protected by copyright. All rights reserved

Description: Aging is a primary risk factor for both neurodegenerative disorders (NDs) and tumors such as adult-onset brain tumors. Since NDs and tumors are severe, disabling, progressive and often incurable conditions, they represent a pressing problem in terms of human suffering and economic costs to the healthcare systems. The current challenge for physicians and researchers is to develop new therapeutic strategies in both areas to improve the patients' quality of life. In addition to genetics and environmental stressors, the increase in cellular oxidative stress as one of the potential common etiologies has been reported for both disorders. Recently, the scientific community has focused on the beneficial effects of dietary antioxidant classes, known as nutraceuticals, such as carotenoids, vitamins and polyphenols. Among these compounds, polyphenols are considered to be one of the most bioactive agents in neurodegeneration and tumor prevention. Despite the beneficial activity of polyphenols, their poor bioavailability and inefficient delivery systems are the main factors limiting their use in medicine and functional food. The development of polymeric nanoparticle-based delivery systems able to encapsulate and preserve polyphenolic compounds may represent a promising tool to enhance their stability, solubility and cell membrane permeation. In the present review we provide an overview of the main polyphenolic compounds used for ND and brain tumor prevention and treatment that explores their mechanisms of action, recent clinical findings and principal factors limiting their application in medicine. This article is protected by copyright. All rights reserved

Description: Adipose-derived stromal/stem cells (ASCs) represent a widely used cell source with multi-lineage differentiation capacity in approaches for tissue engineering and regenerative medicine. Despite the multitude of literature on their differentiation capacity, little is reported about the physiological properties contributing to and controlling the process of lineage differentiation. Direct intercellular communication between adjacent cells via gap junctions has been shown to modulate differentiation processes in other cell types, with connexin 43 (Cx43) being the most abundant isoform of the gap junction-forming connexins. Thus, in the present study we focused on the expression of Cx43 and gap junctional intercellular communication (GJIC) in human ASCs, and its significance for adipogenic differentiation of these cells. Cx43 expression in ASCs was demonstrated histologically and on the gene and protein expression level, and was shown to be greatly positively influenced by cell seeding density. Functionality of gap junctions was proven by dye transfer analysis in growth medium. Adipogenic differentiation of ASCs was shown to be also distinctly elevated at higher cell seeding densities. Inhibition of GJIC by 18α-glycyrrhetinic acid (AGA) significantly compromised adipogenic differentiation, as demonstrated by histology, triglyceride quantification, and adipogenic marker gene expression. Flow cytometry analysis showed a lower proportion of cells undergoing adipogenesis when GJIC was inhibited, further indicating the importance of GJIC in the differentiation process. Altogether, this study demonstrates the impact of direct cell-cell communication via gap junctions on the adipogenic differentiation process of ASCs, and may contribute to further integrate direct intercellular crosstalk in rationales for tissue engineering approaches. This article is protected by copyright. All rights reserved