Autophagy-based unconventional secretion of HMGB1 by keratinocytes plays a pivotal role in psoriatic skin inflammation.
Ontology highlight
ABSTRACT:
SUBMITTER: Wang Z
PROVIDER: S-EPMC8007160 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Dysregulation and abnormal expression of inflammatory mediators by keratinocytes promote the pathogenesis of the skin inflammation such as allergic contact dermatitis (ACD). High-mobility group box 1 (HMGB1) protein, a prototypical damage-associated molecular pattern (DAMP), that is expressed in the nucleus but released extracellularly upon inflammation has gained attention as an accelerator for skin inflammation. However, in vivo role of HMGB1 in ACD and other skin disorders remains to be elusive. In this study, we generated conditional knockout mice in which HMGB1 is deleted in keratinocytes and examined its role in skin inflammation models including 2,4-dinitrofluorobenezene (DNFB)-induced ACD. Unexpectedly, deletion of HMGB1 in keratinocytes exacerbated skin inflammation, accompanied by increased ear thickening. Elevated mRNA expression of interleukin-24 (IL-24), a known cytokine which promotes the pathogenesis of ACD, was also observed in the skin lesion of the mice. In accordance with above observations, both constitutive and IL-4-induced Il24 mRNA expression in vitro was augmented in hmgb1-deficient primary mouse keratinocytes and keratinocyte cell line PAM212 cells. Chromatin immunoprecipitation (ChIP) analysis revealed increased binding of tri-methyl histone H3 (lys4) (H3K4me3), a well-known histone mark for transcription active genes, to the promoter region of the Il24 gene in the hmgb1-deficient cells. ChIP-sequencing data also showed broad changes of H3K4me3 mark in the cells. Thus, HMGB1 in the nucleus dictates histone modifications. In conclusion, our study demonstrated a key role for HMGB1 in keratinocytes in the maintenance of chromatin modification status to protect from exuberant skin inflammation.
2021-01-01 | GSE159695 | GEO
Project description:Increasing evidence suggests an essential function for autophagy in unconventional protein secretion (UPS). However, despite its relevance for the secretion of aggregate-prone proteins, the mechanisms of secretory autophagy in neurons have remained elusive. Here we show that the lower motoneuron disease-associated protein Plekhg5 drives the UPS of Sod1. Mechanistically, Sod1 is sequestered into the intermembrane space of autophagosomes which fuse with secretory lysosomal-related organelles (LROs). Deletion of Plekhg5 in mice disrupts the secretion of these LROs causing Sod1 accumulation at swollen presynaptic sites. A reduced secretion of toxic ALS-linked SOD1G93A following deletion of Plekhg5 in SOD1G93A mice accelerated disease onset while prolonging survival due to an attenuated microglia activation. Using human isogenic iPSC-derived motoneurons we show an impaired secretion of ALS-linked SOD1D90A, which coincided with a reduced PLEKHG5 expression. Our findings highlight an unexpected pathophysiological mechanism that converges two motoneuron disease-associated proteins into a common pathway.
2024-08-28 | GSE269588 | GEO
Project description:Psoriasis is histologically characterized by keratinocytes (KC) hyperproliferation, inflammation, and increased angiogenesis, but the pathological factor responsible for these symptoms is unknown. Here, a neuroendocrine peptide (prokineticin 2, PK2), is highly expressed in human and mouse psoriatic skins but no significant change in other autoimmune diseases, suggesting that PK2 is a psoriasis-specific factor. Bacterial products significantly up-regulated PK2, implying that infection induces PK2 over-expression. PK2 promoted KC and macrophage to produce interleukin-1 (IL-1), the central player of inflammation and psoriasis, which acts on adjacent fibroblast to induce inflammatory cascades and KC hyperproliferation. IL-1 feeds back on macrophages to induce PK2 production to perpetuate PK2-IL-1 positive feedback loop. PK2 also promoted angiogenesis, another psoriatic symptom. In mouse models, PK2 over-expression aggravated psoriasis while its knock-down inhibited pathological development. The results indicate that PK2 over-production perpetuates psoriatic symptoms by creating PK-2-IL-1 vicious loop. PK2 is a central player in psoriasis and a promising psoriasis-specific target.
| S-EPMC5264273 | biostudies-literature
Project description:Protective role of HMGB1 in keratinocytes in skin inflammation
| PRJNA670207 | ENA
Project description:BackgroundHevin is a matricellular protein involved in tissue repair and remodeling via interaction with the surrounding extracellular matrix (ECM) proteins. In this study, we examined the functional role of hevin using a corneal stromal wound healing model achieved by an excimer laser-induced irregular phototherapeutic keratectomy (IrrPTK) in hevin-null (hevin(-/-)) mice. We also investigated the effects of exogenous supplementation of recombinant human hevin (rhHevin) to rescue the stromal cellular components damaged by the excimer laser.Methodology/principal findingsWild type (WT) and hevin (-/-) mice were divided into three groups at 4 time points- 1, 2, 3 and 4 weeks. Group I served as naïve without any treatment. Group II received epithelial debridement and underwent IrrPTK using excimer laser. Group III received topical application of rhHevin after IrrPTK surgery for 3 days. Eyes were analyzed for corneal haze and matrix remodeling components using slit lamp biomicroscopy, in vivo confocal microscopy, light microscopy (LM), transmission electron microscopy (TEM), immunohistochemistry (IHC) and western blotting (WB). IHC showed upregulation of hevin in IrrPTK-injured WT mice. Hevin (-/-) mice developed corneal haze as early as 1-2 weeks post IrrPTK-treatment compared to the WT group, which peaked at 3-4 weeks. They also exhibited accumulation of inflammatory cells, fibrotic components of ECM proteins and vascularized corneas as seen by IHC and WB. LM and TEM showed activated keratocytes (myofibroblasts), inflammatory debris and vascular tissues in the stroma. Exogenous application of rhHevin for 3 days reinstated inflammatory index of the corneal stroma similar to WT mice.Conclusions/significanceHevin is transiently expressed in the IrrPTK-injured corneas and loss of hevin predisposes them to aberrant wound healing. Hevin (-/-) mice develop early corneal haze characterized by severe chronic inflammation and stromal fibrosis that can be rescued with exogenous administration of rhHevin. Thus, hevin plays a pivotal role in the corneal wound healing.
| S-EPMC3841198 | biostudies-literature
Project description:Nuclear protein HMGB1 is secreted in response to various stimuli and functions as a danger-associated molecular pattern. Extracellular HMGB1 induces inflammation, cytokine production, and immune cell recruitment via activation of various receptors. As HMGB1 does not contain an endoplasmic reticulum-targeting signal peptide, HMGB1 is secreted via the endoplasmic reticulum-Golgi independently via an unconventional secretion pathway. However, the mechanism underlying HMGB1 secretion remains largely unknown. Here, we investigated the role of secretory autophagy machinery and vesicular trafficking in HMGB1 secretion. We observed that HSP90AA1 (heat shock protein 90 alpha family class A member 1), a stress-inducible protein, regulates the translocation of HMGB1 from the nucleus to the cytoplasm and its secretion through direct interaction. Additionally, geldanamycin, an HSP90AA1 inhibitor, reduced HMGB1 secretion. GORASP2/GRASP55 (golgi reassembly stacking protein 2), ARF1Q71L (ADP ribosylation factor 1), and SAR1AT39N (secretion associated Ras related GTPase 1A), which promoted unconventional protein secretion, increased HMGB1 secretion. HMGB1 secretion was inhibited by an early autophagy inhibitor and diminished in ATG5-deficient cells even when GORASP2 was overexpressed. In contrast, a late autophagy inhibitor increased HMGB1 secretion under the same conditions. The multivesicular body formation inhibitor GW4869 dramatically decreased HMGB1 secretion under HMGB1 secretion-inducing conditions. Thus, we demonstrated that secretory autophagy and multivesicular body formation mediate HMGB1 secretion.
| S-EPMC8496717 | biostudies-literature
Project description:?1-Antichymotrypsin (?1-ACT) is a specific inhibitor of leukocyte-derived chymotrypsin-like proteases with largely unknown functions in tissue repair. By examining human and murine skin wounds, we showed that following mechanical injury the physiological repair response is associated with an acute phase response of ?1-ACT and the mouse homologue Spi-2, respectively. In both species, attenuated ?1-ACT/Spi-2 activity and gene expression at the local wound site was associated with severe wound healing defects. Topical application of recombinant ?1-ACT to wounds of diabetic mice rescued the impaired healing phenotype. LC-MS analysis of ?1-ACT cleavage fragments identified a novel cleavage site within the reactive center loop and showed that neutrophil elastase was the predominant protease involved in unusual ?1-ACT cleavage and inactivation in nonhealing human wounds. These results reveal critical functions for locally acting ?1-ACT in the acute phase response following skin injury, provide mechanistic insight into its function during the repair response, and raise novel perspectives for its potential therapeutic value in inflammation-mediated tissue damage.
| S-EPMC3190696 | biostudies-literature
Project description:Hypoxia changes the responses of cancer cells to many chemotherapy agents, resulting in chemoresistance. The underlying molecular mechanism of hypoxia-induced drug resistance remains unclear. Pim-1 is a survival kinase, which phosphorylates Bad at serine 112 to antagonize drug-induced apoptosis. Here we show that hypoxia increases Pim-1 in a hypoxia-inducible factor-1alpha-independent manner. Inhibition of Pim-1 function by dominant-negative Pim-1 dramatically restores the drug sensitivity to apoptosis induced by chemotherapy under hypoxic conditions in both in vitro and in vivo tumor models. Introduction of siRNAs for Pim-1 also resensitizes cancer cells to chemotherapy drugs under hypoxic conditions, whereas forced overexpression of Pim-1 endows solid tumor cells with resistance to cisplatin, even under normoxia. Dominant-negative Pim-1 prevents a decrease in mitochondrial transmembrane potential in solid tumor cells, which is normally induced by cisplatin (CDDP), followed by the reduced activity of Caspase-3 and Caspase-9, indicating that Pim-1 participates in hypoxia-induced drug resistance through the stabilization of mitochondrial transmembrane potential. Our results demonstrate that Pim-1 is a pivotal regulator involved in hypoxia-induced chemoresistance. Targeting Pim-1 may improve the chemotherapeutic strategy for solid tumors.
| S-EPMC3358117 | biostudies-literature
Project description:Doxorubicin (DOX), a chemotherapeutic agent, induces a cardiotoxicity referred to as doxorubicin-induced cardiomyopathy (DIC). This cardiotoxicity often limits chemotherapy for malignancies and is associated with poor prognosis. However, the molecular mechanism underlying this cardiotoxicity is yet to be fully elucidated. Here, we show that DOX downregulated glutathione peroxidase 4 (GPx4) and induced excessive lipid peroxidation through DOX-Fe2+ complex in mitochondria, leading to mitochondria-dependent ferroptosis; we also show that mitochondria-dependent ferroptosis is a major cause of DOX cardiotoxicity. In DIC mice, the left ventricular ejection fraction was significantly impaired, and fibrosis and TUNEL+ cells were induced at day 14. Additionally, GPx4, an endogenous regulator of ferroptosis, was downregulated, accompanied by the accumulation of lipid peroxides, especially in mitochondria. These cardiac impairments were ameliorated in GPx4 Tg mice and exacerbated in GPx4 heterodeletion mice. In cultured cardiomyocytes, GPx4 overexpression or iron chelation targeting Fe2+ in mitochondria prevented DOX-induced ferroptosis, demonstrating that DOX triggered ferroptosis in mitochondria. Furthermore, concomitant inhibition of ferroptosis and apoptosis with ferrostatin-1 and zVAD-FMK fully prevented DOX-induced cardiomyocyte death. Our findings suggest that mitochondria-dependent ferroptosis plays a key role in progression of DIC and that ferroptosis is the major form of regulated cell death in DOX cardiotoxicity.
| S-EPMC7253028 | biostudies-literature
Project description:Psoriasis, a chronic inflammatory disease affecting 2-3% of the population, is characterised by epidermal hyperplasia, a sustained pro-inflammatory immune response and is primarily a T-cell driven disease. Previous work determined that Connexin26 is upregulated in psoriatic tissue. This study extends these findings. Biopsies spanning psoriatic plaque (PP) and non-involved tissue (PN) were compared to normal controls (NN). RNA was isolated and subject to real-time PCR to determine gene expression profiles, including GJB2/CX26, GJB6/CX30 and GJA1/CX43. Protein expression was assessed by immunohistochemistry. Keratinocytes and fibroblasts were isolated and used in 3D organotypic models. The pro-inflammatory status of fibroblasts and 3D cultures was assessed via ELISA and RnD cytokine arrays in the presence or absence of the connexin channel blocker Gap27. Connexin26 expression is dramatically enhanced at both transcriptional and translational level in PP and PN tissue compared to NN (>100x). In contrast, CX43 gene expression is not affected, but the protein is post-translationally modified and accumulates in psoriatic tissue. Fibroblasts isolated from psoriatic patients had a higher inflammatory index than normal fibroblasts and drove normal keratinocytes to adopt a "psoriatic phenotype" in a 3D-organotypic model. Exposure of normal fibroblasts to the pro-inflammatory mediator peptidoglycan, isolated from Staphylococcus aureus enhanced cytokine release, an event protected by Gap27. dysregulation of the connexin26:43 expression profile in psoriatic tissue contributes to an imbalance of cellular events. Inhibition of connexin signalling reduces pro-inflammatory events and may hold therapeutic benefit.
| S-EPMC8200029 | biostudies-literature