Photobiomodulation inhibits the activation of neurotoxic microglia and astrocytes by inhibiting Lcn2/JAK2-STAT3 crosstalk after spinal cord injury in male rats.

BACKGROUND: Neurotoxic microglia and astrocytes begin to activate and participate in pathological processes after spinal cord injury (SCI), subsequently causing severe secondary damage and affecting tissue repair. We have previously reported that photobiomodulation (PBM) can promote functional recovery by reducing neuroinflammation after SCI, but little is known about the underlying mechanism. Therefore, we aimed to investigate whether PBM ameliorates neuroinflammation by modulating the activation of microglia and astrocytes after SCI. METHODS: Male Sprague-Dawley rats were randomly divided into three groups: a sham control group, an SCI + vehicle group and an SCI + PBM group. PBM was performed for two consecutive weeks after clip-compression SCI models were established. The activation of neurotoxic microglia and astrocytes, the level of tissue apoptosis, the number of motor neurons and the recovery of motor function were evaluated at different days post-injury (1, 3, 7, 14, and 28 days post-injury, dpi). Lipocalin 2 (Lcn2) and Janus kinase-2 (JAK2)-signal transducer and activator of transcription-3 (STAT3) signaling were regarded as potential targets by which PBM affected neurotoxic microglia and astrocytes. In in vitro experiments, primary microglia and astrocytes were irradiated with PBM and cotreated with cucurbitacin I (a JAK2-STAT3 pathway inhibitor), an adenovirus (shRNA-Lcn2) and recombinant Lcn2 protein. RESULTS: PBM promoted the recovery of motor function, inhibited the activation of neurotoxic microglia and astrocytes, alleviated neuroinflammation and tissue apoptosis, and increased the number of neurons retained after SCI. The upregulation of Lcn2 and the activation of the JAK2-STAT3 pathway after SCI were suppressed by PBM. In vitro experiments also showed that Lcn2 and JAK2-STAT3 were mutually promoted and that PBM interfered with this interaction, inhibiting the activation of microglia and astrocytes. CONCLUSION: Lcn2/JAK2-STAT3 crosstalk is involved in the activation of neurotoxic microglia and astrocytes after SCI, and this process can be suppressed by PBM.

Electromagnetic energy (670 nm) stimulates vasodilation through activation of the large conductance potassium channel (BKCa).

INTRODUCTION: Peripheral artery disease (PAD) is a highly morbid condition in which impaired blood flow to the limbs leads to pain and tissue loss. Previously we identified 670 nm electromagnetic energy (R/NIR) to increase nitric oxide levels in cells and tissue. NO elicits relaxation of smooth muscle (SMC) by stimulating potassium efflux and membrane hyperpolarization. The actions of energy on ion channel activity have yet to be explored. Here we hypothesized R/NIR stimulates vasodilation through activation of potassium channels in SMC. METHODS: Femoral arteries or facial arteries from C57Bl/6 and Slo1-/- mice were isolated, pressurized to 60 mmHg, pre-constricted with U46619, and irradiated twice with energy R/NIR (10 mW/cm2 for 5 min) with a 10 min dark period between irradiations. Single-channel K+ currents were recorded at room temperature from cell-attached and excised inside-out membrane patches of freshly isolated mouse femoral arterial muscle cells using the patch-clamp technique. RESULTS: R/NIR stimulated vasodilation requires functional activation of the large conductance potassium channels. There is a voltage dependent outward current in SMC with light stimulation, which is due to increases in the open state probability of channel opening. R/NIR modulation of channel opening is eliminated pharmacologically (paxilline) and genetically (BKca α subunit knockout). There is no direct action of light to modulate channel activity as excised patches did not increase the open state probability of channel opening. CONCLUSION: R/NIR vasodilation requires indirect activation of the BKca channel.

Ionizing radiation downregulates estradiol synthesis via endoplasmic reticulum stress and inhibits the proliferation of estrogen receptor-positive breast cancer cells.

Breast cancer is a major threat to women's health and estrogen receptor-positive (ER+) breast cancer exhibits the highest incidence among these cancers. As the primary estrogen, estradiol strongly promotes cellular proliferation and radiotherapy, as a standard treatment, exerts an excellent therapeutic effect on ER+ breast cancer. Therefore, we herein wished to explore the mechanism(s) underlying the inhibitory effects of radiation on the proliferation of ER+ breast cancer cells. We used the ER+ breast cancer cell lines MCF7 and T47D, and their complementary tamoxifen-resistant cell lines in our study. The aforementioned cells were irradiated at different doses of X-rays with or without exogenous estradiol. CCK8 and clone-formation assays were used to detect cellular proliferation, enzyme-linked immunosorbent assay (ELISA) to determine estradiol secretion, western immunoblotting analysis and quantitative real-time PCR to evaluate the expression of proteins, and immunofluorescence to track endoplasmic reticulum stress-related processes. Finally, BALB/C tumor-bearing nude mice were irradiated with X-rays to explore the protein expression in tumors using immunohistochemistry. We found that ionizing radiation significantly reduced the phosphorylation of estrogen receptors and the secretion of estradiol by ER+ breast cancer cells. CYP19A (aromatase) is an enzyme located in the endoplasmic reticulum, which plays a critical role in estradiol synthesis (aromatization), and we further demonstrated that ionizing radiation could induce endoplasmic reticulum stress with or without exogenous estradiol supplementation, and that it downregulated the expression of CYP19A through ER-phagy. In addition, ionizing radiation also promoted lysosomal degradation of CYP19A, reduced estradiol synthesis, and inhibited the proliferation of tamoxifen-resistant ER+ breast cancer cells. We concluded that ionizing radiation downregulated the expression of CYP19A and reduced estradiol synthesis by inducing endoplasmic reticulum stress in ER+ breast cancer cells, thereby ultimately inhibiting cellular proliferation.

Disease-Dependent Antiapoptotic Effects of Cannabidiol for Keratinocytes Observed upon UV Irradiation.

Although apoptosis of keratinocytes has been relatively well studied, there is a lack of information comparing potentially proapoptotic treatments for healthy and diseased skin cells. Psoriasis is a chronic autoimmune-mediated skin disease manifested by patches of hyperproliferative keratinocytes that do not undergo apoptosis. UVB phototherapy is commonly used to treat psoriasis, although this has undesirable side effects, and is often combined with anti-inflammatory compounds. The aim of this study was to analyze if cannabidiol (CBD), a phytocannabinoid that has anti-inflammatory and antioxidant properties, may modify the proapoptotic effects of UVB irradiation in vitro by influencing apoptotic signaling pathways in donor psoriatic and healthy human keratinocytes obtained from the skin of five volunteers in each group. While CBD alone did not have any major effects on keratinocytes, the UVB treatment activated the extrinsic apoptotic pathway, with enhanced caspase 8 expression in both healthy and psoriatic keratinocytes. However, endoplasmic reticulum (ER) stress, characterized by increased expression of caspase 2, was observed in psoriatic cells after UVB irradiation. Furthermore, decreased p-AKT expression combined with increased 15-d-PGJ2 level and p-p38 expression was observed in psoriatic keratinocytes, which may promote both apoptosis and necrosis. Application of CBD partially attenuated these effects of UVB irradiation both in healthy and psoriatic keratinocytes, reducing the levels of 15-d-PGJ2, p-p38 and caspase 8 while increasing Bcl2 expression. However, CBD increased p-AKT only in UVB-treated healthy cells. Therefore, the reduction of apoptotic signaling pathways by CBD, observed mainly in healthy keratinocytes, suggests the need for further research into the possible beneficial effects of CBD.

Pulsed Electromagnetic Fields in Bone Healing: Molecular Pathways and Clinical Applications.

In this article, we provide an extensive review of the recent literature of the signaling pathways modulated by Pulsed Electromagnetic Fields (PEMFs) and PEMFs clinical application. A review of the literature was performed on two medical electronic databases (PubMed and Embase) from 3 to 5 March 2021. Three authors performed the evaluation of the studies and the data extraction. All studies for this review were selected following these inclusion criteria: studies written in English, studies available in full text and studies published in peer-reviewed journal. Molecular biology, identifying cell membrane receptors and pathways involved in bone healing, and studying PEMFs target of action are giving a solid basis for clinical applications of PEMFs. However, further biology studies and clinical trials with clear and standardized parameters (intensity, frequency, dose, duration, type of coil) are required to clarify the precise dose-response relationship and to understand the real applications in clinical practice of PEMFs.

Accelerated burn wound healing with photobiomodulation therapy involves activation of endogenous latent TGF-ß1.

The severity of tissue injury in burn wounds from associated inflammatory and immune sequelae presents a significant clinical management challenge. Among various biophysical wound management approaches, low dose biophotonics treatments, termed Photobiomodulation (PBM) therapy, has gained recent attention. One of the PBM molecular mechanisms of PBM treatments involves photoactivation of latent TGF-ß1 that is capable of promoting tissue healing and regeneration. This work examined the efficacy of PBM treatments in a full-thickness burn wound healing in C57BL/6 mice. We first optimized the PBM protocol by monitoring tissue surface temperature and histology. We noted this dynamic irradiance surface temperature-monitored PBM protocol improved burn wound healing in mice with elevated TGF-ß signaling (phospho-Smad2) and reduced inflammation-associated gene expression. Next, we investigated the roles of individual cell types involved in burn wound healing following PBM treatments and noted discrete effects on epithelieum, fibroblasts, and macrophage functions. These responses appear to be mediated via both TGF-ß dependent and independent signaling pathways. Finally, to investigate specific contributions of TGF-ß1 signaling in these PBM-burn wound healing, we utilized a chimeric TGF-ß1/ß3 knock-in (TGF-ß1Lß3/Lß3) mice. PBM treatments failed to activate the chimeric TGF-ß1Lß3/Lß3 complex and failed to improve burn wound healing in these mice. These results suggest activation of endogenous latent TGF-ß1 following PBM treatments plays a key role in burn wound healing. These mechanistic insights can improve the safety and efficacy of clinical translation of PBM treatments for tissue healing and regeneration.

470 nm LED Irradiation Inhibits the Invasiveness of CD133-positive Human Colorectal Cancer Stem Cells by Suppressing the Cyclooxygenase-2/prostaglandin E2 Pathway.

BACKGROUND/AIM: Recurrence and metastasis of cancer caused by cancer stem cells (CSCs) is a challenge to overcome. Low level laser therapy is a new treatment strategy to suppress their invasiveness. We have assessed the inhibitory effects of 470 nm blue LED on the invasiveness of them to determine the molecular mechanisms of anti-invasiveness. MATERIALS AND METHODS: The effects of blue LEDs on their viability, proliferation and invasion were analyzed using MTT and transwell methods. In addition, the anti-invasiveness effect of blue LED on them was evaluated by zymography, semi-quantitative RT-PCR and western blot analysis. RESULTS: Irradiation with blue LED at 3 J/cm2 resulted in inhibition of their viability, proliferation and invasiveness. Their matrix metalloproteinase 2 (MMP-2) and MMP-9 activities were reduced by blue LED irradiation. Semi-quantitative RT-PCR also showed similar results. In addition, western blotting analyses showed that cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) synthesis were significantly inhibited by LED irradiation in CD133+ colorectal CSCs. CONCLUSION: Down-regulation of the COX-2/PGE2 signaling pathway by blue LED irradiation led to reduce expression of MMP-2 and MMP-9, inhibiting the invasiveness of CD133+ colorectal CSC.

Obacunone protects retinal pigment epithelium cells from ultra-violet radiation-induced oxidative injury.

Ultra-violet (UV) radiation (UVR) causes significant oxidative injury to retinal pigment epithelium (RPE) cells. Obacunone is a highly oxygenated triterpenoid limonoid compound with various pharmacological properties. Its potential effect in RPE cells has not been studied thus far. Here in ARPE-19 cells and primary murine RPE cells, obacunone potently inhibited UVR-induced reactive oxygen species accumulation, mitochondrial depolarization, lipid peroxidation and single strand DNA accumulation. UVR-induced RPE cell death and apoptosis were largely alleviated by obacunone. Obacunone activated Nrf2 signaling cascade in RPE cells, causing Keap1-Nrf2 disassociation, Nrf2 protein stabilization and nuclear translocation. It promoted transcription and expression of antioxidant responsive element-dependent genes. Nrf2 silencing or CRISPR/Cas9-induced Nrf2 knockout almost reversed obacunone-induced RPE cytoprotection against UVR. Forced activation of Nrf2 cascade, by Keap1 knockout, similarly protected RPE cells from UVR. Importantly, obacunone failed to offer further RPE cytoprotection against UVR in Keap1-knockout cells. In vivo, intravitreal injection of obacunone largely inhibited light-induced retinal damage. Collectively, obacunone protects RPE cells from UVR-induced oxidative injury through activation of Nrf2 signaling cascade.

Ultrasound May Suppress Tumor Growth, Inhibit Inflammation, and Establish Tolerogenesis by Remodeling Innatome via Pathways of ROS, Immune Checkpoints, Cytokines, and Trained Immunity/Tolerance.

BACKGROUND: The immune mechanisms underlying low-intensity ultrasound- (LIUS-) mediated suppression of inflammation and tumorigenesis remain poorly determined. METHODS: We used microarray datasets from the NCBI GEO DataSet repository and conducted comprehensive data-mining analyses, where we examined the gene expression of 1376 innate immune regulators (innatome genes (IGs) in cells treated with LIUS. RESULTS: We made the following findings: (1) LIUS upregulates proinflammatory IGs and downregulates metastasis genes in cancer cells, and LIUS upregulates adaptive immunity pathways but inhibits danger-sensing and inflammation pathways and promote tolerogenic differentiation in bone marrow (BM) cells. (2) LIUS upregulates IGs encoded for proteins localized in the cytoplasm, extracellular space, and others, but downregulates IG proteins localized in nuclear and plasma membranes, and LIUS downregulates phosphatases. (3) LIUS-modulated IGs act partially via several important pathways of reactive oxygen species (ROS), reverse signaling of immune checkpoint receptors B7-H4 and BTNL2, inflammatory cytokines, and static or oscillatory shear stress and heat generation, among which ROS is a dominant mechanism. (4) LIUS upregulates trained immunity enzymes in lymphoma cells and downregulates trained immunity enzymes and presumably establishes trained tolerance in BM cells. (5) LIUS modulates chromatin long-range interactions to differentially regulate IGs expression in cancer cells and noncancer cells. CONCLUSIONS: Our analysis suggests novel molecular mechanisms that are utilized by LIUS to induce tumor suppression and inflammation inhibition. Our findings may lead to development of new treatment protocols for cancers and chronic inflammation.

The Effect of Cannabidiol on UV-Induced Changes in Intracellular Signaling of 3D-Cultured Skin Keratinocytes.

Human epidermal keratinocytes are constantly exposed to UV radiation. As a result, there is a significant need for safe and effective compounds to protect skin cells against this environmental damage. This study aimed to analyze the effect of phytocannabinoid-cannabinoid (CBD)-on the proteome of UVA/B irradiated keratinocytes. The keratinocytes were cultured in a three-dimensional (3D) system, designed to mimic epidermal conditions closely. The obtained results indicate that CBD protected against the harmful effects of UVA/B radiation. CBD decreased the expression of proinflammatory proteins, including TNFα/NFκB and IκBKB complex and decreased the expression of proteins involved in de novo protein biosynthesis, which are increased in UVA/B-irradiated cells. Additionally, CBD enhanced the UV-induced expression of 20S proteasome subunits. CBD also protected protein structures from 4-hydroxynonenal (HNE)-binding induced by UV radiation, which primarily affects antioxidant enzymes. CBD-through its antioxidant/anti-inflammatory activity and regulation of protein biosynthesis and degradation-protects skin cells against UVA/B-induced changes. In the future, its long-term use in epidermal cells should be investigated.

In vitro effect of curcumin-mediated antimicrobial photodynamic therapy on fibroblasts: viability and cell signaling for apoptosis.

Although it was demonstrated that curcumin-mediated antimicrobial photodynamic therapy (aPDT) is effective for reducing the viability of microbial cells and the vitality of oral biofilms, the cytotoxicity of this therapeutic approach for host cells has not been yet elucidated. Hence, the aim of this study was to evaluate the cytotoxicity and apoptotic effects of curcumin-mediated aPDT on mouse fibroblasts. Cells were treated with 0.6 or 6 µmol.L-1 curcumin combined with 0.075 or 7.5 J.cm-2 LED at 455 nm. Cytotoxicity was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet (CV) assays, while quantitative reverse transcriptase-PCR (qRT-PCR) was used to assess the expression of Bax, Bad, Bcl-2, VDAC-1, cytochrome C, and Fas-L genes for apoptosis. The differences between groups were detected by Kruskal-Wallis and post hoc Dunn's tests for MTT and CV assays and by ANOVA and post hoc Tukey test for qRT-PCR (P < 0.05). The effect of 0.6 µmol.L-1 curcumin plus 0.075 J.cm-2 LED (minimum parameter) did not differ statistically from control group; however, the combination of 0.6 µmol.L-1 curcumin plus 7.5 J.cm-2 LED reduced viable cells in 34%, while the combinations of 6 µmol.L-1 curcumin plus 0.075 and 7.5 J.cm-2 LED reduced viable cells in 47% and 99%, respectively. aPDT increased significantly the relative expression of Bax/Bcl-2, cytochrome C, VDAC-1, and Fas-L genes, without influence on the ratio Bad/Bcl-2. Therefore, curcumin-mediated aPDT activated Bcl-2 apoptosis signaling pathways in mouse fibroblasts regarding present conditions, reducing the viability of cells with the increase of curcumin concentrations and light energies.

The anti-UV properties of Saussurea involucrate Matsum. & Koidz. Via regulating PI3K/Akt pathway in B16F10 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Ultra Violet (UV) radiation is the major reason for reactive oxygen species (ROS) forming, skin cell damage, melanin production, and could horribly cause skin cancer. Saussureae Involucratae Herba (SIH) is the aerial part of Saussurea involucrata Matsum. & Koidz. This Material Medica is popular with both in Uyghur and Chinese medicines filed. SIH is one of the famous species of the Asteraceae family and which prescribed for skin protection from UV-induced damage according to China Pharmacopeia (2020). However, the detailed working mechanism involved is still not elucidated. AIM OF THE STUDY: We would like to probe the potential transduction pathway of SIH against UV-induced skin cell damages in cultured B16F10 cells. METHODS: Western blot, luciferase assay, laser confocal, RT-PCR and flow cytometer were employed here to verify the protective pharmaceutical value of SIH in cultured B16F10 cells after UV pre-treatment. RESULTS: Our result revealed that SIH attenuates ROS formation after UV-induced damage in B16F10 cells in a dose-dependent manner. Moreover, the transcriptional and translational anti-oxidative encoding genes were up-regulated under the presence of SIH. Further studies showed that SIH activated transcriptional activity of anti-oxidant response element (ARE). Moreover, we found that SIH dramatically stimulates PI3K/Akt phosphorylation in cultured B16F10 cells, this result was further verified by its specific inhibitors, LY294002 and Tocris. CONCLUSION: Our findings concluded that SIH protect melanoma cells from UV damages via activating PI3K/Akt signaling and which could provide scientific evidence for anti-UV pharmaceutical values of this herbal extract.

Ghrelin reverts intestinal stem cell loss associated with radiation-induced enteropathy by activating Notch signaling.

BACKGROUD: Exposure to high-dose radiation, such as after a nuclear accident or radiotherapy, elicits severe intestinal damage and is associated with a high mortality rate. In treating patients exhibiting radiation-induced intestinal dysfunction, countermeasures to radiation are required. In principle, the cellular event underlying radiation-induced gastrointestinal syndrome is intestinal stem cell (ISC) apoptosis in the crypts. High-dose irradiation induces the loss of ISCs and impairs intestinal barrier function, including epithelial regeneration and integrity. Notch signaling plays a critical role in the maintenance of the intestinal epithelium and regulates ISC self-renewal. Ghrelin, a hormone produced mainly by enteroendocrine cells in the gastrointestinal tract, has diverse physiological and biological functions. PURPOSE: We investigate whether ghrelin mitigates radiation-induced enteropathy, focusing on its role in maintaining epithelial function. METHODS: To investigate the effect of ghrelin in radiation-induced epithelial damage, we analyzed proliferation and Notch signaling in human intestinal epithelial cell. And we performed histological analysis, inflammatory response, barrier functional assays, and expression of notch related gene and epithelial stem cell using a mouse model of radiation-induced enteritis. RESULTS: In this study, we found that ghrelin treatment accelerated the reversal of radiation-induced epithelial damage including barrier dysfunction and defective self-renewing property of ISCs by activating Notch signaling. Exogenous injection of ghrelin also attenuated the severity of radiation-induced intestinal injury in a mouse model. CONCLUSION: These data suggest that ghrelin may be used as a potential therapeutic agent for radiation-induced enteropathy.

ß-Elemene enhances radiosensitivity in non-small-cell lung cancer by inhibiting epithelial-mesenchymal transition and cancer stem cell traits via Prx-1/NF-kB/iNOS signaling pathway.

Radiation therapy is widely used to treat a variety of malignant tumors, including non-small-cell lung cancer (NSCLC). However, ionizing radiation (IR) paradoxically promotes radioresistance, metastasis and recurrence by inducing epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs). Here, we developed two NSCLC radioresistant (RR) cell lines (A549-RR and H1299-RR) and characterized their motility, cell cycle distribution, DNA damage, and CSC production using migration/invasion assays, flow cytometry, comet assays, and sphere formation, respectively. We also evaluated their tumorigenicity in vivo using a mouse xenograft model. We found that invasion and spheroid formation by A549-RR and H1299-RR cells were increased as compared to their parental cells. Furthermore, as compared to radiation alone, the combination of ß-elemene administration with radiation increased the radiosensitivity of A549 cells and reduced expression of EMT/CSC markers while inhibiting the Prx-1/NF-kB /iNOS signaling pathway. Our findings suggest that NSCLC radioresistance is associated with EMT, enhanced CSC phenotypes, and activation of the Prx-1/NF-kB/iNOS signaling pathway. They also suggest that combining ß-elemene with radiation may be an effective means of overcoming radioresistance in NSCLC.

Early effect of laser irradiation in signaling pathways of diabetic rat submandibular salivary glands.

Low-power laser irradiation (LPLI) is clinically used to modulate inflammation, proliferation and apoptosis. However, its molecular mechanisms are still not fully understood. This study aimed to describe the effects of LPLI upon inflammatory, apoptotic and proliferation markers in submandibular salivary glands (SMGs) in an experimental model of chronic disorder, 24h after one time irradiation. Diabetes was induced in rats by the injection of streptozotocin. After 29 days, these animals were treated with LPLI in the SMG area, and euthanized 24h after this irradiation. Treatment with LPLI significantly decreased diabetes-induced high mobility group box 1 (HMGB1) and tumor necrosis factor alpha (TNF-α) expression, while enhancing the activation of the transcriptional factor cAMP response element binding (CREB) protein. LPLI also reduced the expression of bax, a mitochondrial apoptotic marker, favoring the cell survival. These findings suggest that LPLI can hamper the state of chronic inflammation and favor homeostasis in diabetic rats SMGs.

Electroacupuncture ameliorates cerebral ischemia/reperfusion injury by suppressing autophagy via the SIRT1-FOXO1 signaling pathway.

Cerebral ischemia/reperfusion (CIR) injury occurs when blood flow is restored in the brain, causing secondary damage to the ischemic tissues. Previous studies have shown that electroacupuncture (EA) treatment contributes to brain protection against CIR injury through modulating autophagy. Studies indicated that SIRT1-FOXO1 plays a crucial role in regulating autophagy. Here we investigated the mechanisms underlying the neuroprotective effect of EA and its role in modulating autophagy via the SIRT1-FOXO1 signaling pathway in rats with CIR injury. EA pretreatment at "Baihui", "Quchi" and "Zusanli" acupoints (2/15Hz, 1mA, 30 min/day) was performed for 5 days before the rats were subjected to middle cerebral artery occlusion, and the results indicated that EA pretreatment substantially reduced the Longa score and infarct volume, increased the dendritic spine density and lessened autophagosomes in the peri-ischemic cortex of rats. Additionally, EA pretreatment also reduced the ratio of LC3-II/LC3-I, the levels of Ac-FOXO1 and Atg7, and the interaction of Ac-FOXO1 and Atg7, but increased the levels of p62, SIRT1, and FOXO1. The above effects were abrogated by the SIRT1 inhibitor EX527. Thus, we presume that EA pretreatment elicits a neuroprotective effect against CIR injury, potentially by suppressing autophagy via activating the SIRT1-FOXO1 signaling pathway.

ER stress induced by ER calcium depletion and UVB irradiation regulates tight junction barrier integrity in human keratinocytes.

BACKGROUND: Endoplasmic reticulum (ER) calcium depletion-induced ER stress is a crucial signal for keratinocyte differentiation and barrier homeostasis, but its effects on the epidermal tight junction (TJ) have not been characterized. Ultraviolet B (UVB) causes ER calcium release in keratinocytes and disrupts epidermal TJ, however, the involvement of ER stress in the UVB-induced TJ alterations remains unknown. OBJECTIVES: To investigate the effect of ER stress by pharmacological ER calcium depletion or UVB on the TJ integrity in normal human epidermal keratinocytes (NHEK). METHODS: NHEK were exposed to ER calcium pump inhibitor thapsigargin (Tg) or UVB. ER stress markers and TJ molecules expression, TJ and F-actin structures, and TJ barrier function were analyzed. RESULTS: Tg or UVB exposure dose-dependently triggered unfolded protein response (UPR) in NHEK. Low dose Tg induced the IRE1α-XBP1 pathway and strengthened TJ barrier. Contrary, high dose Tg activated PERK phosphorylation and disrupted TJ by F-actin disorganization. UVB disrupted TJ and F-actin structures dose dependently. IRE1α RNase inhibition induced or exacerbated TJ and F-actin disruption in the presence of low dose Tg or UVB. High dose Tg increased RhoA activity. 4-PBA or Rho kinase (ROCK) inhibitor partially prevented the disruption of TJ and F-actin following high dose Tg or UVB. CONCLUSIONS: ER stress has bimodal effects on the epidermal TJ depending on its intensity. The IRE1α pathway is critical for the maintenance of TJ integrity during mild ER stress. Severe ER stress-induced UPR or ROCK signalling mediates the disruption of TJ through cytoskeletal disorganization during severe ER stress.

Photobiomodulation with 630-nm LED radiation inhibits the proliferation of human synoviocyte MH7A cells possibly via TRPV4/PI3K/AKT/mTOR signaling pathway.

Phototherapy has been used to treat postoperative pain and inflammatory response in rheumatoid arthritis. Confidence in this approach, however, is impaired by lack of understanding of the light-triggered cellular and molecular mechanisms. The purpose of this study was to characterize the response of human synoviocyte MH7A cells to visible LED red light in an attempt to elucidate the associated action mechanism. Human synoviocyte MH7A cells were treated with 630-nm LED light after stimulation of tumor necrosis factor-α (TNF-α). The effects of light radiation on cell proliferation and migration were detected by MTT assay and scratch test. The expressions of inflammatory cytokines were measured using RT-qPCR. This was followed by detection of the levels of extracellular proteins IL-6 and IL-8 after differential radiation. Furthermore, the expression levels and activation of proteins on PI3K/AKT/mTOR signaling pathway were examined with Western blot. In terms of the proliferation and migration, repeated radiation with LED red light (630 nm, 26 and 39 J/cm2) exerted an inhibitory effect on synoviocyte MH7A cells. Expression of inflammatory factors (IL-6, IL-1ß, IL-8, and MMP-3) was reduced; meanwhile, the expression of anti-inflammatory factor IL-10 was promoted. At the protein level, treatment with 39 J/cm2 of LED red light could decrease the level of extracellular protein (IL-6 and IL-8) and affect the expression and phosphorylation of proteins on TRPV4/PI3K/AKT/mTOR signaling pathway induced by TNF-α. These results demonstrated that LED red light (630 nm) inhibits proliferation and migration of MH7A cells. The growth-inhibiting effects of LED red light on human synoviocyte MH7A cells appear to be associated with regulation of the TRPV4/PI3K/AKT/mTOR signaling pathway.

KMRC011, an agonist of toll-like receptor 5, mitigates irradiation-induced tissue damage and mortality in cynomolgus monkeys.

In the study here, the potential applicability of KMRC011 - an agonist of toll-like receptor-5 - as a countermeasure for radiation toxicities was evaluated. Following a single 5.5 Gy total body irradiation (TBI, surface absorbed dose = 7 Gy) of Co60 γ-rays, mortality rates and degrees of pathological lesions that developed over 80 days were compared in monkeys that received TBI only and a group that was injected once with KMRC011 (10 µg/kg) after TBI. Compared to the TBI-only hosts (80%), the death rate was significantly improved by the use of KMRC011 (40%), all deaths in both groups occurred in the period from Days 19-24 post-TBI. Further analysis of monkeys that survived until the end of the experiment showed that AST and ALT levels were elevated only in the TBI group, and that radiation-induced tissue damage was alleviated by the KMRC011 injection. Additionally, expression of cell death-related proteins was lower in tissues from the KMRC011-treated hosts than in those in the TBI-only group. Other measured parameters, including body weight, food uptake, and hematological values did not significantly differ between the two groups over the entire period. The results of this study, thus demonstrate that KMRC011 could potentially be used as a medical countermeasure for the treatment of acute radiation exposure.

Photobiomodulation therapy decreases free fatty acid generation and release in adipocytes to ameliorate insulin resistance in type 2 diabetes.

Excessive circulating free fatty acids (FFA) cause insulin resistance in peripheral tissues by inhibiting the proximal insulin signaling pathway. White adipose tissue (WAT) is a primary source of FFA generation and release through triglyceride (TG) hydrolysis. Thus, reducing excessive lipolysis in adipocytes ameliorates whole-body insulin resistance in type 2 diabetes. Here, we found that a noninvasive photobiomodulation therapy (PBMT), decreased FFA generation and release in WATs from high-fat diet (HFD)-fed mice and diabetic db/db mice. Meanwhile, plasma FFA and TG levels were reduced in two mouse models after PBMT. PBMT promoted mitochondrial reactive oxygen species (ROS) generation, which inhibited phosphatase and tensin homologue (PTEN) and promoted protein kinase B (AKT) activation. Photoactivation of AKT inhibited the transcriptional activity of Forkhead box transcription factor O1 (FoxO1), reducing expression of lipolytic enzymes and FFA generation and release. Eliminating ROS elimination or inhibiting AKT blocked the effects of the laser therapy in vivo and in vitro. Taken together, PBMT suppresses FFA generation and release in insulin-resistant adipocytes, contributing to improvement of insulin resistance in mouse models of type 2 diabetes.