The pivotal role of osteopontin in UV-induced skin inflammation in a mouse model.

Osteopontin (OPN) is a pro-inflammatory protein that influences bone remodelling, wound healing, angiogenesis, allergic inflammation, and skin diseases such as psoriasis, contact dermatitis and skin cancer. However, the role of OPN in the skin remains unclear. Therefore, this study aimed to investigate the role of OPN in the skin, particularly in the context of ultraviolet (UV) irradiation-induced inflammation.

UV Irradiation Increases Appetite and Prevents Body Weight Gain through the Upregulation of Norepinephrine in Mice.

UV irradiation of the human skin downregulates lipid synthesis and adipokine production in subcutaneous fat. Recent evidence has suggested that UV exposure limits body weight gain in mouse models of obesity. However, the relationship between norepinephrine and UV irradiation has not been previously reported.

Thunb Flower Extract Attenuates Ultraviolet-Induced Photoaging in Skin Cells and Hairless Mice.

Ethanol extract (RET) of Thunb flowers and its subfractions in ethylacetate (REA) or -butanol subfractions (RBT) were reported to have potent antioxidative and anti-inflammatory activities. In this study, we investigated if those flower (RMF) extracts prevent ultraviolet (UV)-induced biochemical damages leading to photoaging. In keratinocyte or dermal fibroblasts, RET, REA, and RBT treatments with UV irradiation significantly decreased reactive oxygen species (ROS), interleukin (IL)-6, IL-8, and matrix metalloproteinase (MMP)-1 levels through suppression of nuclear factor kappa B and mitogen-activated protein kinases.

Topical treatment with a cathepsin G inhibitor, β-keto-phosphonic acid, blocks ultraviolet irradiation-induced basement membrane damage in hairless mouse skin.

Background: Ultraviolet light (UV) exposure contributes various effects to skin including damage of the basement membrane. Cathepsin G (CTSG) belongs to serine protease family, and its upregulation is involved in wrinkle formation by chronic UV irradiation. However, the effect of CTSG on the basement membrane damage in skin remains unclear.

Topical or oral treatment of peach flower extract attenuates UV-induced epidermal thickening, matrix metalloproteinase-13 expression and pro-inflammatory cytokine production in hairless mice skin.

Background/objectives: Ultraviolet radiation (UV) is a major cause of skin photoaging. Previous studies reported that ethanol extract (PET) of (L.) Batsch flowers (PPF, peach flowers) and its subfractions, particularly the ethylacetate (PEA) and n-butanol extracts (PBT), have potent antioxidant activity and attenuate the UV-induced matrix metalloproteinase (MMP) expression in human skin cells.

UV irradiation to mouse skin decreases hippocampal neurogenesis and synaptic protein expression via HPA axis activation.

The skin senses external environment, including ultraviolet light (UV). Hippocampus is a brain region that is responsible for memory and emotion. However, changes in hippocampus by UV irradiation to the skin have not been studied.

A synthetic peptide blocking TRPV1 activation inhibits UV-induced skin responses.

Background: Transient receptor potential type 1 (TRPV1) can be activated by ultraviolet (UV) irradiation, and mediates UV-induced matrix metalloproteinase (MMP)-1 and proinflammatory cytokines in keratinocytes. Various chemicals and compounds targeting TRPV1 activation have been developed, but are not in clinical use mostly due to their safety issues.

Objective: We aimed to develop a novel TRPV1-targeting peptide to inhibit UV-induced responses in human skin.

Perilla frutescens leaves extract ameliorates ultraviolet radiation-induced extracellular matrix damage in human dermal fibroblasts and hairless mice skin.

Ethnopharmacological Relevance: Perilla frutescens (L.) Britt. (Lamiaceae) is a traditional herb that is consumed in East Asian countries as a traditional medicine.

Activation of Peroxisome Proliferator-Activated Receptor Alpha Improves Aged and UV-Irradiated Skin by Catalase Induction.

Peroxisome proliferator-activated receptor alpha (PPARα) is a nuclear hormone receptor involved in the transcriptional regulation of lipid metabolism, fatty acid oxidation, and glucose homeostasis. Its activation stimulates antioxidant enzymes such as catalase, whose expression is decreased in aged human skin. Here we investigated the expression of PPARα in aged and ultraviolet (UV)-irradiated skin, and whether PPARα activation can modulate expressions of matrix metalloproteinase (MMP)-1 and procollagen through catalase regulation.

Role of Arachidonic Acid in Promoting Hair Growth.

Background: Arachidonic acid (AA) is an omega-6 polyunsaturated fatty acid present in all mammalian cell membranes, and involved in the regulation of many cellular processes, including cell survival, angiogenesis, and mitogenesis. The dermal papilla, composed of specialized fibroblasts located in the bulb of the hair follicle, contributes to the control of hair growth and the hair cycle.

Objective: This study investigated the effect of AA on hair growth by using in vivo and in vitro models.

Development of a Model for Chemotherapy-Induced Alopecia: Profiling of Histological Changes in Human Hair Follicles after Chemotherapy.

Optimized research models are required to further understand the pathogenesis and prophylaxis of chemotherapy-induced alopecia. Our aim was to develop a mouse model for chemotherapy-induced alopecia by follicular unit transplantation of human hair follicles onto immunodeficient mice. Twenty-two weeks after transplantation, a single dose of cyclophosphamide (Cph) was administered to mice in the Cph100 (100 mg/kg) and Cph150 (150 mg/kg) groups.

A role of placental growth factor in hair growth.

Background: The dermal papilla (DP) comprises specialized mesenchymal cells at the bottom of the hair follicle and plays a pivotal role in hair formation, anagen induction and the hair cycle. In this study, DPs were isolated from human hair follicles and serially subcultured. From each subculture at passages 1, 3, and 5 (n=4), we compared gene expression profiles using mRNA sequencing.

Pretreatment of epidermal growth factor promotes primary hair recovery via the dystrophic anagen pathway after chemotherapy-induced alopecia.

Epidermal growth factor (EGF) is not only a cell growth stimulant but also has a catagen-inducing effect. Because chemotherapeutic agents primarily damage anagen hair follicles, it would be important to investigate whether catagen inducers have beneficial effects in chemotherapy-induced alopecia (CIA). We pretreated hair follicles with topical EGF-liposomal solution in the C57BL/6 mouse model of cyclophosphamide-induced alopecia and observed the catagen-inducing property and damage response pathway after CIA.