Defining variant-resistant epitopes targeted by SARS-CoV-2 antibodies: A global consortium study.

Antibody-based therapeutics and vaccines are essential to combat COVID-19 morbidity and mortality after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Multiple mutations in SARS-CoV-2 that could impair antibody defenses propagated in human-to-human transmission and spillover or spillback events between humans and animals. To develop prevention and therapeutic strategies, we formed an international consortium to map the epitope landscape on the SARS-CoV-2 spike protein, defining and structurally illustrating seven receptor binding domain (RBD)­directed antibody communities with distinct footprints and competition profiles. Pseudovirion-based neutralization assays reveal spike mutations, individually and clustered together in variants, that affect antibody function among the communities. Key classes of RBD-targeted antibodies maintain neutralization activity against these emerging SARS-CoV-2 variants. These results provide a framework for selecting antibody treatment cocktails and understanding how viral variants might affect antibody therapeutic efficacy.

Effects of palmitoyl-KVK-L-ascorbic acid on skin wrinkles and pigmentation.

Wrinkle formation and abnormal pigmentation are major clinical alterations associated with skin aging. As the aim of our study was to investigate the effects of palmitoyl-KVK-L-ascorbic acid on skin aging, the anti-wrinkle and depigmentation effects of palmitoyl-KVK-L-ascorbic acid were evaluated by measuring collagen expression in dermal fibroblast cells and inhibition of melanogenesis in B16F1 cells, respectively. The anti-aging effect of palmitoyl-KVK-L-ascorbic acid cream was also evaluated against a placebo cream in a clinical trial. Our results confirmed that the expression of type Ι collagen in dermal fibroblast cells treated with palmitoyl-KVK-L-ascorbic acid (0.1-4 µg/mL) increased in a dose-dependent manner. In B16F1 cells, treatment with 20 µg/mL palmitoyl-KVK-L-ascorbic acid reduced the melanin content by approximately 20% compared to alpha-melanocyte stimulating hormone treatment. In the clinical trial, application of palmitoyl-KVK-L-ascorbic acid cream led to an improvement in skin roughness and lightness in 12 and 8 weeks, respectively. Our data show that palmitoyl-KVK-L-ascorbic acid is an effective anti-aging agent that reduces wrinkles and abnormal skin pigmentation.

Melatonin ameliorates alcohol-induced bile acid synthesis by enhancing miR-497 expression.

Alcoholic liver disease is a major cause of chronic liver disease worldwide, and cannabinoid receptor type 1 (CB1R) is involved in a diverse metabolic diseases. B-cell translocation gene 2 (BTG2) and yin yang 1 (YY1) are a potent regulator of biological conditions. Melatonin plays a crucial role in regulating diverse physiological functions and metabolic homeostasis. MicroRNAs are key regulators of various biological processes. Herein, we demonstrate that melatonin improves bile acid synthesis in the liver of alcohol-fed mice by controlling miR-497 expression. The level of bile acid and the expression of Cb1r, Btg2, Yy1, and bile acid synthetic enzymes were significantly elevated in the livers of Lieber-DeCarli alcohol-fed mice. The overexpression of Btg2 enhanced Yy1 gene expression and bile acid production, whereas disrupting the CB1R-BTG2-YY1 cascade protected against the bile acid synthesis caused by alcohol challenge. We identified an alcohol-mediated YY1 binding site on the cholesterol 7α-hydroxylase (Cyp7a1) gene promoter using promoter deletion analysis and chromatin immunoprecipitation assays. Notably, melatonin attenuated the alcohol-stimulated induction of Btg2, Yy1 mRNA levels and bile acid production by promoting miR-497. Overexpression of a miR-497 mimic dramatically diminished the increase of Btg2 and Yy1 gene expression as well as bile acid production by alcohol, whereas this phenomenon was reversed by miR-497 inhibitor. These results demonstrate that the upregulation of miR-497 by melatonin represses alcohol-induced bile acid synthesis by attenuating the BTG2-YY1 signaling pathway. The melatonin-miR497 signaling network may provide novel therapeutic targets for the treatment of hepatic metabolic dysfunction caused by the alcohol-dependent pathway.

Synergistic Inhibition of Tumor Necrosis Factor-Alpha-Stimulated Pro-Inflammatory Cytokine Expression in HaCaT Cells by a Combination of Rapamycin and Mycophenolic Acid.

BACKGROUND: Keratinocytes release various pro-inflammatory cytokines, chemokines, and adhesion molecules such as intercellular adhesion molecule 1 (ICAM-1) in response to cytokines such as tumor necrosis factor (TNF)-α and interferon (IFN)-γ. Rapamycin and mycophenolic acid (MPA) have potent immunosuppressive activity because they inhibit lymphocyte proliferation. OBJECTIVE: We investigated the effects of rapamycin and MPA on the expression of inflammation-related factors such as ICAM-1 and inducible nitric oxide synthase (iNOS), pro-inflammatory cytokines and chemokines, and related signaling pathways in TNF-α-stimulated HaCaT cells. METHODS: The viability of HaCaT cells treated with rapamycin and MPA was confirmed using MTT assay. The expression of various cytokines such as interleukin (IL)-1ß, IL-6, and IL-8; inflammation-related factors such as ICAM-1 and iNOS; and the activation of mitogen activated protein kinase (MAPK) signaling pathways mediated by extracellular signal-related kinases (ERK), p38, and c-Jun N-terminal kinases (JNK) in TNF-α-stimulated HaCaT cells were confirmed using reverse transcription-polymerase chain reaction and western blotting. RESULTS: Combined treatment of TNF-α-induced HaCaT cells with rapamycin and MPA decreased ICAM-1 and iNOS expression and ERK and p38 activation more than treatment with either drug alone. The most significant decrease was observed with a combination of rapamycin (80 nM) and MPA (20 nM). These results show that co-treatment with these agents has a synergistic anti-inflammatory effect by blocking the activation of the ERK/p38 MAPK signaling pathway and thus suppressing the TNF-α-induced expression of ICAM-1 and iNOS. CONCLUSION: The combination of rapamycin and MPA could potentially be used as a therapeutic approach in inflammatory skin diseases.

Berberine regulates melanin synthesis by activating PI3K/AKT, ERK and GSK3ß in B16F10 melanoma cells.

Berberine, an isoquinoline alkaloid, has a wide range of beneficial properties, including anti-bacterial, anti-inflammatory, anti-cancer, and cholesterol-lowering effects. Recently findings suggest that berberine improves glucose and lipid metabolism disorders. In the present study, we examined the mechanism underlying the inhibitory effect of berberine on α-melanocyte-stimulating hormone (α-MSH)-stimulated B16F10 melanoma cells. The results showed that berberine attenuated α-MSH induction of the microphthalmia-associated transcription factor (MITF) and tyrosinase in a dose-dependent manner. To elucidate the mechanism underlying the inhibitory effect of berberine, we examined the effect of α-MSH-stimulated phosphorylation of PI3K/AKT, ERK, and GSK3ß. The results showed that treatment with berberine resulted in a reduction in the phosphorylation of PI3K/AKT, ERK, and GSK3ß. Taken together, the results suggested that berberine inhibits melanin synthesis and tyrosinase activity by downregulating the expression of MITF and tyrosinase. Thus, these findings may contribute to the potential application of berberine in the prevention and treatment of skin pigmentation disorders.

Inhibitory effects of Saururi chinensis extracts on melanin biosynthesis in B16F10 melanoma cells.

Saururus chinensis has been used in folk medicine in Korea for the treatment of edema, jaundice, gonorrhea, and several inflammatory diseases. Saururi chinensis extracts (SCE) have demonstrated anti-inflammatory and anti-oxidant activities, as well as anti-asthmatic, antihypertensive, anti-angiogenic, and therapeutic activities for atopic dermatitis. However, the inhibitory activity of SCE on the melanogenesis signaling pathway is not completely understood. This study examined the effects of SCE on the melanogenesis signaling pathway activated by α-melanocyte-stimulating hormone (α-MSH). We found that SCE inhibited melanin production in a dose-dependent manner without causing cytotoxicity in B16F10 cells. Interestingly, SCE decreased α-MSH-induced tyrosinase activity in B16F10 cells but did not inhibit tyrosinase activity under cell-free conditions. The results of this study indicate that SCE may reduce pigmentation by way of an indirect, nonenzymatic mechanism. We also found that SCE decreased α-MSH-induced microphthalmia-associated transcription factor (MITF) and tyrosinase expression and induced the activation of extracellular signal-regulated kinase (ERK). These results suggest that the depigmenting effect of SCE may result from downregulation of MITF and tyrosinase expression due to increased ERK activity. Thus, our results provide evidence that SCE might be useful as a potential skin-whitening agent.

Successful treatment of alopecia areata with topical calcipotriol.

Alopecia areata (AA) is an inflammatory hair loss of unknown etiology. AA is chronic and relapsing, and no effective cure or preventive treatment has been established. Vitamin D was recently reported to be important in cutaneous immune modulation as well as calcium regulation and bone metabolism. It is well known that areata is common clinical finding in patients with vitamin D deficiency, vitamin D-resistant rickets, or vitamin D receptor (VDR) mutation. The biological actions of vitamin D3 derivatives include regulation of epidermal cell proliferation and differentiation and modulation of cytokine production. These effects might explain the efficacy of vitamin D3 derivatives for treating AA. In this study, we report a 7-year-old boy with reduced VDR expression in AA, recovery of whom was observed by topical application of calcipotriol, a strong vitamin D analog.

A comparison of neuropeptide expression in skin with allergic contact dermatitis in human and mouse.

BACKGROUND: Allergic contact dermatitis (ACD) is a manifestation of a cell-mediated immune response, but its mechanism remains unknown. Recently, we investigated whether ACD involves various neuropeptides. Substance P (SP) is a neuropeptide that is known to act as a neurokinin receptor when the immune response is initiated. Calcitonin gene-related peptide (CGRP) is a distinct typical neuropeptide and, with SP, induces the immune response. Neuropeptides in neurogenic inflammation are regulated by the inactivation of receptors and enzymes that can cause neuropeptide degradation (e.g. angiotensin-converting enzyme [ACE]), but no enzyme that can degrade SP and CGRP has yet been reported. METHODS: We investigated changes in the expression of SP and CGRP, as representative of typical neuropeptides, in ACD skin in mouse and human and the effect of ACE expression on the degradation of these neuropeptides using reverse transcription polymerase chain reaction and immunoblot assay. We also examined the relationship between ACD and neuropeptides in skin tissue from human ACD subjects and mice with induced ACD by analyzing cytokine expression and the results of hematoxylin and eosin staining and immunofluorescence assay. RESULTS: Expression of SP, CGRP, and ACE was higher in skin tissues from animals with acute ACD than in normal animal skin. However, CGRP expression in human skin with acute ACD was lower than in normal skin, unlike expression of SP and ACE, both of which were higher in ACD human skin than in normal human skin. CONCLUSIONS: We found different patterns of neuropeptide expression in human versus mouse skin. These neuropeptide activities were influenced by an increase in neuropeptide degrading enzymes. Our findings show that when SP is produced, expression of CGRP is suppressed in human skin with ACD. The reduction of CGRP expression in patients with acute ACD is caused by mast cells activated by SP.

Transdermal drug delivery using disk microneedle rollers in a hairless rat model.

BACKGROUND: Transdermal drug delivery systems (TDDSs) represent more reliable and consistent methods of drug dosing than oral administration. However, TDDSs can administer only low molecular weight (MW) drugs and require a power source. Disk microneedle rollers facilitate the passage of low and high MW substances through the direct perforation of the stratum corneum and dermis, without stimulating dermal nerves. OBJECTIVES: We investigated in vitro whether disk microneedle rollers, developed for the Diskneedle Therapy System (DTS™) in South Korea, can deliver drugs effectively through the skin of hairless rats. METHODS: The disk microneedle rollers used in the DTS™ are metal and consist of several plates bearing microneedles of graded lengths (0.15 mm, 0.25 mm, 0.50 mm). To test in vitro permeation, the skin of a hairless rat was mounted in a Franz diffusion cell system and rolled with a disk roller without microneedles and with rollers fitted with microneedles of each size. Rhodamine B base (80 µl) was applied to the skin for 24 hours, 48 hours, and 72 hours, and dye permeation was detected at 543 nm. Dye binding to the skin was also confirmed using fluorescence microscopy at six hours after the application of rhodamine B. RESULTS: Use of the disk microneedle roller increased the skin penetrance of rhodamine B base in hairless rats in accordance with microneedle length, as assessed using a fluorescence penetration test. CONCLUSIONS: Disk microneedle rollers, as designed for the DTS™, can be used for transdermal drug delivery. Microneedles can be selected according to the length appropriate for each application.

The Safety Evaluation of a Potent Angiogenic Activator, Synthetic Peptide (SFKLRY-NH2) for the Skin Application.

A novel synthetic hexapeptide (SFKLRY-NH2) that displays angiogenic activity has been identified by positional scanning of a synthetic peptide combinatorial library (PS-SPCL). This study was carried out to investigate the irritation of the SFKLRY-NH2 on the skin. The tests were performed on the basis of Korea Food and Drug Administration (KFDA) guidelines. In results, cell toxicity is not appeared for SFKLRY-NH2 in HaCaT cells and B16F10 cells. SFKLRY-NH2 induced no skin irritation at low concentration (10 µM), mild irritation at high concentration (10mM). We consider that this result is helpful for saying about the safety of SFKLRY-NH2 in clinical use.