Caffeine Protects Skin from Oxidative Stress-Induced Senescence through the Activation of Autophagy

Biomarkers, oxidative stress and autophagy in skin aging

Aging is a major cause of many degenerative diseases. The most intuitive consequence of aging is mainly manifested on the skin, resulting in cumulative changes in skin structure, function and appearance, such as increased wrinkles, laxity, elastosis, telangiectasia, and aberrant pigmentation of the skin. Unlike other organs of the human body, skin is not only inevitably affected by the intrinsic aging process, but also affected by various extrinsic environmental factors to accelerate aging, especially ultraviolet (UV) radiation. Skin aging is a highly complex and not fully understood process, and the lack of universal biomarkers for the definitive detection and evaluation of aging is also a major research challenge. Oxidative stress induced by the accumulation of reactive oxygen species (ROS) can lead to lipid, protein, nucleic acid and organelle damage, thus leading to the occurrence of cellular senescence, which is one of the core mechanisms mediating skin aging. Autophagy can maintain cellular homeostasis when faced with different stress conditions and is one of the survival mechanisms of cell resistance to intrinsic and extrinsic stress. Autophagy and aging have many features in common and may be associated with skin aging mediated by different factors. Here, we summarize the changes and biomarkers of skin aging, and discuss the effects of oxidative stress and autophagy on skin aging.

SIRT3 deficiency delays diabetic skin wound healing via oxidative stress and necroptosis enhancement

Sirtuin 3 (SIRT3) plays a vital role in several dermatological diseases. However, the role and detailed mechanism of SIRT3 in diabetic wound healing are unknown well yet. To explore possible involvement of SIRT3 and necroptosis in diabetic skin wound healing, SIRT3 knockout (KO) mice and 129S1/SvImJ wild‐type (WT) mice were injected with streptozotocin (STZ), and mice skin fibroblasts were exposed to high glucose (HG). It was found that SIRT3 expression decreased in the skin of diabetic patients. SIRT3 deficiency delayed healing rate, reduced blood supply and vascular endothelial growth factor expression, promoted superoxide production, increased malondialdehyde (MDA) levels, decreased total antioxidant capacity (T‐AOC), reduced superoxide dismutase (SOD) activity and aggravated ultrastructure disorder in skin wound of diabetic mice. SIRT3 deficiency inhibited mice skin fibroblasts migration with HG stimulation, which was restored by SIRT3 overexpression. SIRT3 deficiency also suppressed α‐smooth muscle actin (α‐SMA) expression, enhanced superoxide production but decreased mitochondrial membrane potential with HG stimulation after scratch. SIRT3 deficiency further elevated receptor‐interacting protein kinase 3 (RIPK3), RIPK1 and caspase 3 expression both in vitro and in vivo. Collectively, SIRT3 deficiency delayed skin wound healing in diabetes, the mechanism might be related to impaired mitochondria function, enhanced oxidative stress and increased necroptosis. This may provide a novel therapeutic target to accelerate diabetic skin wound healing.

Shikonin induces colorectal carcinoma cells apoptosis and autophagy by targeting galectin-1/JNK signaling axis

Colorectal carcinoma (CRC) is the third most common malignant tumor pathology worldwide. Despite progress in surgical procedures and therapy options, CRC is still a considerable cause of cancer-related mortality. In this study, we tested the antitumor effects of shikonin in CRC and tried to identify its potential mechanism. The potential target, molecular mechanism as well as in vitro and in vivo antitumor effects of shikonin in CRC cells were determined by an integrative protocol including quantitative proteomics, RT-PCR, western blotting, RNA interference and overexpression, apoptosis and autophagy assays, etc. Galectin-1 was a potential target of shikonin from the iTRAQ-based proteomic analysis in shikonin-treated SW620 cell. The overexpression and RNA silencing of galectin-1 in two CRC cells suggested that the shikonin sensitivity was correlation to galectin-1 levels. The ROS accumulation induced by shikonin was important to the formation of galectin-1 dimers. Dimer galectin-1 was found to be associated with the activation of JNK and downstream apoptosis or autophagy. Moreover, through functional in vitro studies, we showed that differences in galectin-1 level affected tumor cell proliferation, migration, and invasion. In summary, shikonin induced CRC cells apoptosis and autophagy by targeting galectin-1 and JNK signaling pathway both in vitro and in vivo, which suggested a potential novel therapy target for CRC.

Two-dimensional nanomaterials beyond graphene for antibacterial applications: current progress and future perspectives

The marked augment of drug-resistance to traditional antibiotics underlines the crying need for novel replaceable antibacterials. Research advances have revealed the considerable sterilization potential of two-dimension graphene-based nanomaterials. Subsequently, two-dimensional nanomaterials beyond graphene (2D NBG) as novel antibacterials have also demonstrated their power for disinfection due to their unique physicochemical properties and good biocompatibility. Therefore, the exploration of antibacterial mechanisms of 2D NBG is vital to manipulate antibacterials for future applications. Herein, we summarize the recent research progress of 2D NBG-based antibacterial agents, starting with a detailed introduction of the relevant antibacterial mechanisms, including direct contact destruction, oxidative stress, photo-induced antibacterial, control drug/metallic ions releasing, and the multi-mode synergistic antibacterial. Then, the effect of the physicochemical properties of 2D NBG on their antibacterial activities is also discussed. Additionally, a summary of the different kinds of 2D NBG is given, such as transition-metal dichalcogenides/oxides, metal-based compounds, nitride-based nanomaterials, black phosphorus, transition metal carbides, and nitrides. Finally, we rationally analyze the current challenges and new perspectives for future study of more effective antibacterial agents. This review not only can help researchers grasp the current status of 2D NBG antibacterials, but also may catalyze breakthroughs in this fast-growing field.

"Shanghuo" increases disease susceptibility: Modern significance of an old TCM theory

ETHNOPHARMACOLOGICAL RELEVANCE

"Shanghuo", a concept based on Traditional Chinese Medicine (TCM) theory, describes a status of Yin-Yang imbalance when Yang overwhelms Yin. The imbalance of Yin-Yang resembles the breaking of homeostasis and manifests by the impaired physiological functions, which leads to the onset, recurrence, and progression of diseases. Since ancient times, Chinese Materia Medica (CMM), such as herbal tea, has been applied as a treatment for "Shanghuo".

AIM OF THE STUDY

This review is aimed to describe the origin of "Shanghuo" from the Yin-Yang theory in TCM, as well as explore the relevance and correlations between "Shanghuo" and diseases susceptibility from the perspective of modern medicine. We also propose several strategies from CMM to improve the status of "Shanghuo" for the purpose of treating diseases.

METHODS

Systematic research of articles with keywords including Shanghuo, Yin-Yang, emotional stress and disease susceptibility was done by using the literature databases (Web of Science, Google Scholar, PubMed, CNKI). Related books, PhD and master's dissertations were also researched. Full scientific plant names were validated by "The Plant List" (www.theplantlist.org).

RESULTS

To date, a large number of publications have reported research on sub-health status, but studies about the theory or intervention of "Shanghuo" are rarely found. The articles we reviewed indicate that accumulated emotional stress is critical for the cause of "Shanghuo". As a status similar to sub-health, "Shanghuo" is also manifested by impaired physiological functions and decreased nonspecific resistance, which increase susceptibility to various diseases. What's more, some studies highlight the importance of TCM treatment towards "Shanghuo" in maintaining normal physiological functions, such as immunity, lipid metabolism and ROS clearance.

CONCLUSIONS

Researches on "Shanghuo" and its mechanism are every rare currently and are in need of investigation in the future. Studies on disease susceptibility recently are mostly about susceptible genes that relate to a few parts of people, however, for most of the people, accumulated emotional stress or other stressors is accountable for the susceptibility of diseases. Given that emotional stress plays an important factor in the causation of "Shanghuo", we reviewed the articles about this relevance and discussed the connection of "Shanghuo" with disease susceptibility in a novel perspective. In addition, we have reviewed the disease susceptibility model of restraint stress from its biochemical manifestation to application in CMM assessment. Although it would be a breakthrough in evaluating CMM efficacy of attenuating disease-susceptibility, understanding the comprehensive theory and establishing more models of "Shanghuo" would be required in further investigation.

Nanotechnology and nanomaterial-based no-wash electrochemical biosensors: from design to application

Nanotechnology and nanomaterial based electrochemical biosensors (ECBs) have achieved great development in many fields, such as clinical diagnosis, food analysis, and environmental monitoring. Nowadays, the single-handed pursuit of sensitivity and accuracy cannot meet the demands of detection in many in situ and point-of-care (POC) circumstances. More and more attention has been focused on simplifying the operation procedure and reducing detection time, and thus no-wash assay has become one of the most effective ways for the continuous development of ECBs. However, there are many challenges to realize no-wash detection in the real analysis, such as redox interferences, multiple impurities, non-conducting protein macromolecules, etc. Furthermore, the complex detection circumstance in different application fields makes the realization of no-wash ECBs more complicated and difficult. Thanks to the updated nanotechnology and nanomaterials, in-depth analysis of the obstacles in the detection process and various methods for fabricating no-wash ECBs, most issues have been largely resolved. In this review, we have systematically analyzed the nanomaterial based design strategy of the state-of-the-art no-wash ECBs in the past few years. Following that, we summarized the challenges in the detection process of no-wash ECBs and their applications in different fields. Finally, based on the summary and analysis in this review, we also evaluated and discussed future prospects from the design to the application of ECBs.

Update on the role of Sirtuin 3 in cell differentiation: A major metabolic target that can be pharmacologically controlled

Cell differentiation is a fundamental biological event in which a precursor stem cell is turning into a specialized somatic cell. It is thus crucial for the development, tissue turnover and regeneration in mammals. Among the numerous changes taking place in a cell during a differentiation programme, the biology of mitochondria, the central organelle mainly responsible for energy homeostasis and stress adaptation, is deeply modified. These modifications are now well recognized as taking an active part to the completion of the differentiation programme. Indeed, mitochondrial biogenesis and metabolic shift are observed during cell differentiation, adapting many syntheses, calcium homeostasis, ATP and reactive oxygen species production, to the needs. These mitochondrial functions are substantially regulated by the post-translational modifications of the mitochondrial proteins among which lysine acetylation is essential. This mitoacetylome is then globally controlled by the balance between spontaneous/enzymatically-catalysed protein acetylation and the NAD⁺-dependent deacetylation mediated by Sirtuin 3. This enzyme is now considered as a major regulator of the function of the organelle. Regarding the requirement of these mitochondrial adaptations, the subsequent growing interest for this enzyme recently extended to the investigation of the mechanisms driving cell differentiation. This review summarizes the currently available information about the significance of SIRT3 in cell differentiation in physio-pathological contexts. We also suggest a control of the differentiation-activated autophagy by SIRT3, a hypothesis supported by recent findings establishing a causal link between SIRT3 and autophagy. Eventually, an update on the present pharmacological modulators of SIRT3 in a context of cell differentiation is discussed.

Reduction of Aging-Induced Oxidative Stress and Activation of Autophagy by Bilberry Anthocyanin Supplementation via the AMPK-mTOR Signaling Pathway in Aged Female Rats

Oxidative-stress-induced senescence constitutes a great risk factor for chronic diseases. Therefore, ameliorating oxidative-stress-induced senescence is expected to prevent chronic diseases. The beneficial effects of bilberry anthocyanin (BA) on healthy aging were evaluated using 12 month old, aging female SD rats in this study. The experimental results suggested that consumption of a middle-dose of BA (MBA) appreciably increased the relative liver mass by 7.34% when compared with that of the AC group. Furthermore, BA significantly increased the total antioxidant capacity, total superoxide dismutase activity, and catalase activities; decreased malondialdehyde, serum low-density lipoprotein cholesterol (LDL-C), serum total cholesterol (TC), serum triglyceride (TG), and glycated serum protein (GSP) levels; and reduced TC/high-density lipoprotein cholesterol (HDL-C) and LDL-C/HDL-C ratios. In addition, MBA decreased the activity of fecal bacterial enzymes and increased the content of fecal short-chain fatty acids. The Western blot results showed that MBA significantly upregulated the expression of OCLN, ZO-1, and autophagy-related proteins (ATP6 V0C, ATG4D, and CTSB) in aging rats. Moreover, it also showed that MBA induced the phosphorylation of AMPK and FOXO3a and inhibited the phosphorylation of mTOR, which indicated that bilberry anthocyanin induced autophagy via the AMPK-mTOR signaling pathways. This induction of autophagy further promoted oxidative stress resistance effects and intestinal epithelial barrier function of bilberry anthocyanin in aging female rats.

Caffeine Inhibits NLRP3 Inflammasome Activation by Suppressing MAPK/NF-κB and A2aR Signaling in LPS-Induced THP-1 Macrophages

Excessive inflammation induced by various risk factors is associated with the development of bronchopulmonary dysplasia (BPD). Caffeine exerts potent anti-inflammatory effects as a clinical preventive medicine for BPD. Recently, NLRP3 inflammasome activation has been demonstrated to be essential for the pathogenesis of BPD. In the present study, we aimed to investigate the effects of caffeine on NLRP3 inflammasome activation in LPS-induced THP-1 macrophages and to explore the underlying the detailed mechanism. We found that caffeine significantly reduced NLRP3 expression, ASC speck formation, and caspase 1 cleavage and therefore decreased IL-1β and IL-18 secretion in THP-1 macrophages. Caffeine also markedly decreased the phosphorylation levels of MAPK and NF-κB pathway members, further suppressing the translocation of NF-κB in THP-1 macrophages. Moreover, silencing of the caffeine-antagonized adenosine A2a receptor (A2aR) significantly decreased cleaved caspase 1 expression in THP-1 macrophages by reducing ROS production. Given these findings, we conclude that caffeine inhibits NLRP3 inflammasome activation by suppressing MAPK/NF-κB signaling and A2aR-associated ROS production in LPS-induced THP-1 macrophages.