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1.
Front Immunol ; 15: 1395288, 2024.
Article in English | MEDLINE | ID: mdl-38903518

ABSTRACT

An 8-year-old female child presented with patchy hair loss for 1 year, accompanied by eyebrow loss for 6 months. Microscopic examination of the hair confirmed the features of active stage alopecia areata, with a Severity of Alopecia Tool (SALT) score of 70%. The diagnosis was severe alopecia areata. The patient had a history of atopic dermatitis since infancy, with recurrent episodes of scattered papules and pruritus for 8 years. Initial treatment involved subcutaneous injections of dupilumab 300mg every 2 weeks for 6 months, resulting in a reduction of SALT score to 20% and improvement of atopic dermatitis symptoms. Discontinuation of Dupilumab and initiation of daily oral Baricitinib at a dose of 2mg for a duration of 5 months. According to the SALT score evaluation, the severity of hair loss was less than 10% and there was significant regrowth of hair. No significant adverse reactions were observed during the treatment period.


Subject(s)
Alopecia Areata , Antibodies, Monoclonal, Humanized , Azetidines , Dermatitis, Atopic , Purines , Pyrazoles , Sulfonamides , Humans , Alopecia Areata/drug therapy , Alopecia Areata/diagnosis , Dermatitis, Atopic/drug therapy , Female , Purines/administration & dosage , Purines/adverse effects , Child , Azetidines/administration & dosage , Azetidines/adverse effects , Azetidines/therapeutic use , Pyrazoles/administration & dosage , Pyrazoles/therapeutic use , Pyrazoles/adverse effects , Sulfonamides/administration & dosage , Sulfonamides/adverse effects , Sulfonamides/therapeutic use , Antibodies, Monoclonal, Humanized/administration & dosage , Antibodies, Monoclonal, Humanized/therapeutic use , Antibodies, Monoclonal, Humanized/adverse effects , Treatment Outcome , Severity of Illness Index , Drug Therapy, Combination
2.
J Cosmet Dermatol ; 23(7): 2490-2495, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38500297

ABSTRACT

BACKGROUND: There is a strong correlation between alopecia areata (AA) and the development of white hair. The AA presents itself in many clinical manifestations of depigmented hair as the condition advances. It is uncommon for unpigmented hair to extensively regrow for more than one hair growth cycle in AA and successful conversion to pigmented hair after treatment has not yet been reported. AIM: We report two case studies involving the persistent regrowth of white hair after AA that became pigmented through treatment. PATIENTS: In the first case study, a 47-year-old woman with AA exhibited a fully regrown head of hair, which remained unpigmented. However, after 2 years of treatment with oral methylprednisolone and compound glycopyrrolate, her hair eventually regained its normal pigmentation. In the second case study, a 7-year-old boy with diffuse AA received compound glycyrrhizin (50 mg once daily) and methylprednisolone (4 mg orally once daily) for 3 years. RESULTS: The both patients experienced regrowth of black hair on his entire head, with occasional white hairs. It is hypothesized that the aforementioned medications may regulate immunity by influencing melanocytes or melanin-associated antigens; however, the precise mechanism must be validated through additional histopathological and molecular analysis. CONCLUSION: A larger patient group, possibly in randomized controlled trials, is needed to determine how the indicated treatment affects hair repigmentation after AA. Therefore, more patients must be included for more substantial outcomes from this study.


Subject(s)
Alopecia Areata , Hair Color , Methylprednisolone , Humans , Alopecia Areata/drug therapy , Alopecia Areata/pathology , Female , Hair Color/drug effects , Middle Aged , Male , Methylprednisolone/administration & dosage , Child , Hair/growth & development , Hair/drug effects , White
3.
Chin Med J (Engl) ; 137(3): 329-337, 2024 Feb 05.
Article in English | MEDLINE | ID: mdl-37519215

ABSTRACT

BACKGROUND: Pathological scars are a disorder that can lead to various cosmetic, psychological, and functional problems, and no effective assessment methods are currently available. Assessment and treatment of pathological scars are based on cutaneous manifestations. A two-photon microscope (TPM) with the potential for real-time non-invasive assessment may help determine the under-surface pathophysiological conditions in vivo . This study used a portable handheld TPM to image epidermal cells and dermal collagen structures in pathological scars and normal skin in vivo to evaluate the effectiveness of treatment in scar patients. METHODS: Fifteen patients with pathological scars and three healthy controls were recruited. Imaging was performed using a portable handheld TPM. Five indexes were extracted from two dimensional (2D) and three dimensional (3D) perspectives, including collagen depth, dermo-epidermal junction (DEJ) contour ratio, thickness, orientation, and occupation (proportion of collagen fibers in the field of view) of collagen. Two depth-dependent indexes were computed through the 3D second harmonic generation image and three morphology-related indexes from the 2D images. We assessed index differences between scar and normal skin and changes before and after treatment. RESULTS: Pathological scars and normal skin differed markedly regarding the epidermal morphological structure and the spectral characteristics of collagen fibers. Five indexes were employed to distinguish between normal skin and scar tissue. Statistically significant differences were found in average depth ( t = 9.917, P <0.001), thickness ( t = 4.037, P <0.001), occupation ( t = 2.169, P <0.050), orientation of collagen ( t = 3.669, P <0.001), and the DEJ contour ratio ( t = 5.105, P <0.001). CONCLUSIONS: Use of portable handheld TPM can distinguish collagen from skin tissues; thus, it is more suitable for scar imaging than reflectance confocal microscopy. Thus, a TPM may be an auxiliary tool for scar treatment selection and assessing treatment efficacy.


Subject(s)
Cicatrix , Skin , Humans , Cicatrix/diagnostic imaging , Skin/pathology , Collagen , Imaging, Three-Dimensional/methods
4.
Phytomedicine ; 114: 154773, 2023 Jun.
Article in English | MEDLINE | ID: mdl-36990011

ABSTRACT

BACKGROUND: Diabetic wounds represent a severe clinical challenge in which impaired M2 macrophage polarization and continuous macrophage glycolysis play crucial roles. Calycosin-7-glucoside (CG) is an isoflavone component in Astragali Radix (AR), which has become a research focus for treating diabetic wounds following reports indicating that it has anti-inflammatory effects. However, the mechanism through which CG can treat diabetic wounds is yet to be deciphered. PURPOSE: This study aimed to evaluate the therapeutic effect of CG on diabetic wounds and its underlying mechanism. METHODS: The potential mechanism underlying the treatment of diabetic wounds by CG was screened using bioinformatics. The therapeutic effects of CG were then investigated using a db/db diabetic wound model. Moreover, an LPS- and IFN-γ-induced RAW264.7 cell inflammation model was used to elucidate the mechanism underlying the therapeutic effects of CG against diabetic wounds. RESULTS: Network pharmacology predicted that the AMPK pathway could be the main target through which CG treats diabetic wounds. In db/db diabetic mice, CG could accelerate wound healing and promote granulation tissue regeneration. Protein chip technology revealed that CG increased the production of M-CSF, G-CSF, GM-CSF, IL-10, IL-13, and IL-4 but not that of MCP-1, IL-1ß, IL-1α, TNF-α, and TNF-RII. Moreover, CG elevated the proportion of Ly6CLo/- anti-inflammatory monocytes in peripheral blood and M2 macrophages in the wound. The ELISA and flow cytometry analyses revealed that CG enhanced the levels of IL-10, VEGF, CD206, and Arg-1 expression whereas it considerably reduced the levels of IL-1, IL-6, IL-12, TNF-α, CD86, and iNOS expression. Meanwhile, CG increased the macrophage mitochondrial membrane potential and decreased the mitochondrial ADP/ATP ratio and glycolysis rate of M1 macrophages through the ROS/AMPK/STAT6 pathway. CONCLUSIONS: The network pharmacology and molecular dockin identified the AMPK pathway as a critical pathway for treating diabetic wounds using topical CG application. CG was found to promote anti-inflammatory monocyte recruitment and decrease the mitochondrial glycolysis rate to induce M2 macrophage polarization via the ROS/AMPK/STAT6 pathway. These results suggest that CG might be a promising therapeutic agent for diabetic wounds.


Subject(s)
Diabetes Mellitus, Experimental , Isoflavones , Mice , Animals , Interleukin-10 , Molecular Docking Simulation , Tumor Necrosis Factor-alpha , Diabetes Mellitus, Experimental/metabolism , Glycosides , Network Pharmacology , AMP-Activated Protein Kinases , Reactive Oxygen Species , Wound Healing , Anti-Inflammatory Agents
5.
Phytomedicine ; 106: 154309, 2022 Nov.
Article in English | MEDLINE | ID: mdl-35994846

ABSTRACT

BACKGROUND: Inefficient differentiation of oligodendrocyte precursor cells (OPCs) is one of the significant pathological obstacles of myelin repair and provides an essential therapeutic target against behavioral dysfunction in various neurodegenerative diseases, especially in secondary progressive multiple sclerosis (SPMS). Ginsenoside Rg1 (Rg1) has traditionally been recognized as a protector of neuronal damages, preventing its degeneration. PURPOSE: We investigated the effects of Rg1 on myelin regeneration-mediated by OPCs and its therapeutic significance in SPMS. METHODS: A cuprizone (CPZ) model was established and then administered with Rg1 specific for evaluations of functional recovery and remyelination. In vitro, the primary mouse OPCs were isolated and cultured for examining their ability of myelin repair. Furthermore, a chronic experimental autoimmune encephalomyelitis (EAE) model was utilized to assess the therapeutic value on SPMS. RESULTS: We found that Rg1 promoted functional recovery of the demyelinated mice, including spatial memory, motor function, and anxiety-like behavior. Histologically, Rg1 enhanced myelin-genesis as proven by myelin staining and microstructures of myelin observed by transmission electron microscope. Furthermore, Rg1 significantly increased Olig2+ oligodendrocyte lineage cells in callosum, implying that the pro-remyelination effect of Rg1 was closely correlated to the enhanced differentiation of OPCs. We further demonstrated that Rg1 increased the survival and proliferation of OPCs as well as induced maturation in oligodendrocytes (OLs). Molecular analysis showed that Rg1 transduced the pro-differentiation signaling programmed by the GSK3ß/ß-Catenin pathway. Notably, relying on its pro-remyelination effects, Rg1 ameliorated severity and histopathology of EAE disease. CONCLUSION: By paving the way for OPCs differentiation, Rg1 could maintain the integrity of myelin and is a promising candidate for functional recovery in demyelinating diseases.


Subject(s)
Encephalomyelitis, Autoimmune, Experimental , Oligodendrocyte Precursor Cells , Remyelination , Animals , Cell Differentiation , Cuprizone/metabolism , Cuprizone/pharmacology , Cuprizone/therapeutic use , Disease Models, Animal , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Ginsenosides , Glycogen Synthase Kinase 3 beta/metabolism , Mice , Mice, Inbred C57BL , Myelin Sheath/metabolism , Remyelination/physiology , beta Catenin/metabolism
6.
Phytomedicine ; 95: 153864, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34923236

ABSTRACT

BACKGROUND: Psoriasis is a psychosomatic immune skin disease with psychological factors contributing to the disease. Substance P (SP) is highly expressed in the psoriatic lesions of patients and is involved in pathological disease progression. Tribulus terrestris L. has been used as a Chinese herbal medicine for disease prevention for thousands of years. Terrestrosin D (TED) has been identified as the effective monomeric component of Tribulus terrestris L.. PURPOSE: We investigated whether TED could reverse imiquimod-induced psoriatic lesions, and then, investigated its potential mechanism of action both in vivo and in vitro. METHODS: 5% imiquimod cream was applied onto the backs of mice for 6 days to induce psoriasis-like skin lesions. The psoriatic area and severity index (PASI) was then used for scoring disease severity. Pathological changes and Ki-67 expression levels in skin lesions were measured using hematoxylin and eosin (H&E) and immunofluorescence staining after TED administration. The in vivo and in vitro expression levels of inflammatory cytokines, the ratio of DCs, and SP were measured using ProcartaPlex Mouse Cytokine panels, flow cytometry, and western blotting. Behavioral assessments were determined using the open field and elevated plus-maze (EPM) test. RESULTS: TED decreased PASI scores, epidermal thickness, Ki-67 expression levels, the ratio of DCs in the spleen, and secretion of IL-12p70, IL-18, and TNF-α in imiquimod-induced psoriasis-like murine models. Furthermore, TED increased IL-10 secretion levels, improved behavior, and down-regulated the expression levels of SP. Additionally, TED inhibited the in vitro maturation and activation of SP-induced CD11c+ DCs and the release of IL-12p70 and IL-23. CONCLUSION: TED reduced DCs maturation, down-regulated the expression levels of inflammatory factors, and improved skin lesions and behavior of psoriasis-like murine models by inhibiting the interaction between Substance P and Dendritic cells.


Subject(s)
Psoriasis , Substance P , Animals , Cell Proliferation , Cytokines , Dendritic Cells , Disease Models, Animal , Imiquimod , Mice , Mice, Inbred BALB C , Psoriasis/chemically induced , Psoriasis/drug therapy , Saponins , Skin
7.
Chin Med ; 16(1): 111, 2021 Nov 02.
Article in English | MEDLINE | ID: mdl-34727961

ABSTRACT

BACKGROUND: Common chronic wounds include diabetic ulcers, venous ulcers, and pressure ulcers. The traditional Chinese medicine Huiyang Shengji decoction (HYSJD) has been shown to promote the healing of diabetic chronic wounds, however, its pharmacological mechanism is still unclear. PURPOSE: This study aimed to determine the mechanism of HYSJD in promoting the healing of diabetic chronic skin ulcers. METHODS: Ultra-performance liquid chromatography was combined with tandem mass spectrometry (UPLC-MS/MS) to analyze the main components of HYSJD and the absorbed components in mouse serum at 30 min after oral administration of HYSJD. db/db mouse models for chronic skin ulcers were constructed by full-thickness skin resection. Wound tissues at day 7 post wound formation were used to perform microarray analysis of growth factors and chemokine expression. GO and KEGG enrichment analysis was performed on differentially expressed proteins. ELISA assays were used to measure differential expressed cytokines in the serum and Western blot analysis was used to determine the expression levels of related pathway proteins in the skin wounds. RESULTS: UPLC-MS/MS analysis showed that the main chemical components of HYSJD were flavonoids, terpenes, alkaloids, phenylpropanoids, and carbohydrates. At 30 min after oral administration of HYSJD, five absorbed components were detected in the serum, these included formononetin, calycosin, hypaconitine, calycosin-7-glucoside, and sinapic acid. HYSJD was found to increase the wound healing rate in chronic skin ulcers in db/db mice at days 3, 7, and 14 post wound formation, and promote the proliferation of epidermal cells. Two proteins that were differentially expressed between the different groups, i.e., IGF-1 and EGFR, were further validated. Serum ELISA assays showed that serum EGFR in the HYSJD treatment group was significantly increased. KEGG pathway analysis suggested that the PI3K/AKT pathway involved in HYSJD promoting the proliferation of epidermal cells in chronic wounds in db/db mice. Experimental verification showed that HYSJD activated the PI3K/AKT signaling pathway in mouse wound skin. CONCLUSION: HYSJD promotes the proliferation of epidermal cells in chronic diabetic wounds by increasing EGFR expression in the wounds and activating the PI3K/AKT signaling pathway. Our study provides an experimental basis for the pharmacological mechanism of HYSJD.

8.
Nat Commun ; 12(1): 4853, 2021 08 11.
Article in English | MEDLINE | ID: mdl-34381046

ABSTRACT

SMAD4 is mutated in human lung cancer, but the underlying mechanism by which Smad4 loss-of-function (LOF) accelerates lung cancer metastasis is yet to be elucidated. Here, we generate a highly aggressive lung cancer mouse model bearing conditional KrasG12D, p53fl/fl LOF and Smad4fl/fl LOF mutations (SPK), showing a much higher incidence of tumor metastases than the KrasG12D, p53fl/fl (PK) mice. Molecularly, PAK3 is identified as a downstream effector of Smad4, mediating metastatic signal transduction via the PAK3-JNK-Jun pathway. Upregulation of PAK3 by Smad4 LOF in SPK mice is achieved by attenuating Smad4-dependent transcription of miR-495 and miR-543. These microRNAs (miRNAs) directly bind to the PAK3 3'UTR for blockade of PAK3 production, ultimately regulating lung cancer metastasis. An inverse correlation between Smad4 and PAK3 pathway components is observed in human lung cancer. Our study highlights the Smad4-PAK3 regulation as a point of potential therapy in metastatic lung cancer.


Subject(s)
Lung Neoplasms/pathology , MicroRNAs/genetics , Smad4 Protein/metabolism , p21-Activated Kinases/metabolism , 3' Untranslated Regions , Animals , Cell Movement , Gene Expression Regulation, Neoplastic , Humans , JNK Mitogen-Activated Protein Kinases/metabolism , Loss of Function Mutation , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Mice , MicroRNAs/metabolism , Neoplasm Metastasis , Proto-Oncogene Proteins c-jun/metabolism , Signal Transduction , Smad4 Protein/genetics , Transcriptional Activation , p21-Activated Kinases/genetics
9.
Article in English | MEDLINE | ID: mdl-34211577

ABSTRACT

Chronic nonhealing cutaneous wounds are a thorny problem in the field of surgery because of their prolonged and unhealed characteristics. Huiyang Shengji extract (HSE) is an extract of traditional Chinese medicine prescription for treating chronic wounds. This study aims to investigate the regulation of M1 macrophages on fibroblast proliferation and secretion and the intervention mechanism of Huiyang Shengji extract. We found that the effects of HSFs stimulated with paracrine factors from M1 macrophages were as follows: the proliferation of HSFs was reduced, the expression of MKI-67 was downregulated, and the content and gene expression of the inflammation factors and fibroblast MMPs were increased, while the content and gene expression of TIMP-1 are decreased, the content of human fibroblasts secreting type I collagen (COL1A1) and type III collagen (COL3A1) was decreased, and the TGF-ß1/Smad3 signaling pathway was inhibited. Interestingly, HSE inhibited these effects of M1 macrophages on human fibroblasts after the intervention, and the inhibitory effect was related to the concentration. In conclusion, M1 macrophages caused changes in HSFs and secretion, while HSE has a specific regulatory effect on the proliferation and secretion of fibroblasts caused by M1 macrophages.

10.
J Cosmet Dermatol ; 20(8): 2538-2541, 2021 Aug.
Article in English | MEDLINE | ID: mdl-33356005

ABSTRACT

Alopecia for patients with discoid lupus erythematosus can sometimes be a refractory condition, where mixed infiltrates of T lymphocytes and histiocytes leads to destruction of hair follicles, which might cause permanent scarring. Early diagnosis and timely treatment can achieve hair regeneration and prevent further disease progression. Concentrated growth factor, a novel autologous plasma extract, contains various growth factors that could promote tissue regeneration. In this article, we report a case of cell growth factor combined with corticosteroids for the treatment of discoid lupus erythematosus alopecia. This case study concludes with satisfactory clinical effect.


Subject(s)
Lupus Erythematosus, Discoid , Adrenal Cortex Hormones/therapeutic use , Alopecia/drug therapy , Alopecia/etiology , Cicatrix/pathology , Humans , Intercellular Signaling Peptides and Proteins , Lupus Erythematosus, Discoid/complications , Lupus Erythematosus, Discoid/drug therapy
11.
Medicine (Baltimore) ; 99(41): e21913, 2020 Oct 09.
Article in English | MEDLINE | ID: mdl-33031257

ABSTRACT

INTRODUCTION: The incidence of psoriasis vulgaris is increasing worldwide. Chronic recurrence of the disease, as well as accompanying cardiovascular disease, metabolic syndrome, and depression has affected the physical and mental health of these patients. Psoriasis vulgaris is a difficult and major disease in the dermatology field. Short-term curative effects using conventional therapy for psoriasis vulgaris has made major strides. However, traditional Chinese medicine (TCM) treatment has long-term curative advantages for psoriasis vulgaris but lacks the scientific and clinical evidence for its use. This study intends to demonstrate and provide scientific and clinical evidence for the use of TCM to delay the recurrence of psoriasis vulgaris. METHODS AND ANALYSIS: This will be a prospective, multicenter cohort study. We intend to recruit 1521 psoriasis vulgaris patients from 14 hospitals in Beijing, Tianjin, and Hebei. Treatment will be based on the diagnosis specifications and clinical practice guidelines of TCM and conventional therapy. During inclusion and the subsequent follow-up period, doctors through electronic case reports will collect different therapeutic TCM regimens and conventional therapy that were administered. Information on life condition, skin lesions at each visit, World Health Organization Quality of Life Instruments, Zung Self-rating Anxiety Scale, Zung Self-assessment of Depression, laboratory examinations, incidence of new rash and recurrence during the remission and recurrence stages will be recorded. ETHICS AND DISSEMINATION: The clinical trial protocol for this study was approved by the ethics committee of the Beijing hospital of TCM affiliated to capital medical university (Ethics number: 2019BL02-010-02). We will publish and present our results at national and international conferences and in peer-reviewed journals specialized in dermatology. TRIAL REGISTRATION: This protocol has been registered in clinicaltrials. gov (ChiCTR1900021629).


Subject(s)
Medicine, Chinese Traditional , Psoriasis/therapy , Humans , Multicenter Studies as Topic , Prospective Studies
12.
Medicine (Baltimore) ; 99(4): e18886, 2020 Jan.
Article in English | MEDLINE | ID: mdl-31977896

ABSTRACT

RATIONALE: Giant keloids often have indications for surgical resection, but postoperative reconstruction of the skin and high recurrence of keloids are a challenge for clinical treatment. This article reports a rare successful treatment of a giant keloid in the anterior chest wall by multistage surgery combined with radiotherapy, which is why this case is meaningful. PATIENT CONCERNS: A 66-year-old woman presented a giant keloid with ulcerations and severe itching on the anterior chest wall. She had a history of keloid disease for more than 10 years, and had been treated by multiple operations, with no success. DIAGNOSES: The patient was diagnosed as keloid based on her history and symptoms. Histopathology findings supported our diagnosis. INTERVENTIONS: We successfully excised the keloid after 5 operations and 2 rounds of electron-beam radiotherapy, which was applied at 24 hours after the 4th and 5th operation. OUTCOMES: There was no sign of recurrence over the follow-up period of 24 months. LESSONS: The combination of multistage surgery and radiotherapy presents as a good choice for the treatment of giant keloids.


Subject(s)
Dermatologic Surgical Procedures/methods , Keloid/surgery , Thoracic Wall/surgery , Aged , Female , Humans , Keloid/pathology , Keloid/radiotherapy , Postoperative Period , Radiotherapy, Adjuvant , Skin/pathology , Thoracic Wall/pathology
13.
Cell Death Differ ; 27(6): 1795-1806, 2020 06.
Article in English | MEDLINE | ID: mdl-31767934

ABSTRACT

Lung cancer is one of the cancers with highest morbidity and mortality rates and the metastasis of lung cancer is a leading cause of death. Mechanisms of lung cancer metastasis are yet to be fully understood. Herein, we demonstrate that mice deficient for REGγ, a proteasome activator, exhibited a significant reduction in tumor size, numbers, and metastatic rate with prolonged survival in a conditional Kras/p53 mutant lung cancer model. REGγ enhanced the TGFß-Smad signaling pathway by ubiquitin-ATP-independent degradation of Smad7, an inhibitor of the TGFß pathway. Activated TGFß signaling in REGγ-positive lung cancer cells led to diminished expression of E-cadherin, a biomarker of epithelial-mesenchymal transitions (EMT), and elevated mesenchymal markers compared with REGγ-deficient lung cancer cells. REGγ overexpression was found in lung cancer patients with metastasis, correlating with the reduction of E-Cadherin/Smad7 and a poor prognosis. Overall, our study indicates that REGγ promotes lung cancer metastasis by activating TGF-ß signaling via degradation of Smad7. Thus, REGγ may serve as a novel therapeutic target for lung cancers with poor prognosis.


Subject(s)
Antigens, CD/metabolism , Cadherins/metabolism , Lung Neoplasms/metabolism , Pancreatitis-Associated Proteins/metabolism , Smad7 Protein/metabolism , A549 Cells , Animals , Epithelial-Mesenchymal Transition , Humans , Mice , Mice, Inbred C57BL , Mice, Knockout , Transforming Growth Factor beta/antagonists & inhibitors
14.
EMBO J ; 38(20): e101430, 2019 10 15.
Article in English | MEDLINE | ID: mdl-31475738

ABSTRACT

E2F7 and E2F8 act as tumor suppressors via transcriptional repression of genes involved in S-phase entry and progression. Previously, we demonstrated that these atypical E2Fs are degraded by APC/CCdh1 during G1 phase of the cell cycle. However, the mechanism driving the downregulation of atypical E2Fs during G2 phase is unknown. Here, we show that E2F7 is targeted for degradation by the E3 ubiquitin ligase SCFcyclin F during G2. Cyclin F binds via its cyclin domain to a conserved C-terminal CY motif on E2F7. An E2F7 mutant unable to interact with SCFcyclin F remains stable during G2. Furthermore, SCFcyclin F can also interact and induce degradation of E2F8. However, this does not require the cyclin domain of SCFcyclin F nor the CY motifs in the C-terminus of E2F8, implying a different regulatory mechanism than for E2F7. Importantly, depletion of cyclin F causes an atypical-E2F-dependent delay of the G2/M transition, accompanied by reduced expression of E2F target genes involved in DNA repair. Live cell imaging of DNA damage revealed that cyclin F-dependent regulation of atypical E2Fs is critical for efficient DNA repair and cell cycle progression.


Subject(s)
Cyclins/metabolism , DNA Repair , E2F7 Transcription Factor/metabolism , G2 Phase/physiology , Proteolysis , Repressor Proteins/metabolism , Cell Cycle Checkpoints , Cyclins/genetics , DNA Damage , DNA Replication , E2F7 Transcription Factor/genetics , HeLa Cells , Humans , Protein Binding , Repressor Proteins/genetics , Ubiquitin-Protein Ligases/genetics , Ubiquitin-Protein Ligases/metabolism , Ubiquitination
15.
Nat Commun ; 7: 10761, 2016 Feb 22.
Article in English | MEDLINE | ID: mdl-26899380

ABSTRACT

Increasing incidence of inflammatory bowel disorders demands a better understanding of the molecular mechanisms underlying its multifactorial aetiology. Here we demonstrate that mice deficient for REGγ, a proteasome activator, show significantly attenuated intestinal inflammation and colitis-associated cancer in dextran sodium sulfate model. Bone marrow transplantation experiments suggest that REGγ's function in non-haematopoietic cells primarily contributes to the phenotype. Elevated expression of REGγ exacerbates local inflammation and promotes a reciprocal regulatory loop with NFκB involving ubiquitin-independent degradation of IκBɛ. Additional deletion of IκBɛ restored colitis phenotypes and inflammatory gene expression in REGγ-deficient mice. In sum, this study identifies REGγ-mediated control of IκBɛ as a molecular mechanism that contributes to NFκB activation and promotes bowel inflammation and associated tumour formation in response to chronic injury.


Subject(s)
Autoantigens/metabolism , Colitis/enzymology , I-kappa B Kinase/metabolism , NF-kappa B/metabolism , Proteasome Endopeptidase Complex/metabolism , Animals , Colitis/chemically induced , Colitis/complications , Colonic Neoplasms/etiology , Dextran Sulfate , HCT116 Cells , HEK293 Cells , Humans , Intestinal Mucosa/metabolism , Mice, Inbred C57BL , Mice, Knockout
16.
J Biol Chem ; 290(18): 11729-40, 2015 May 01.
Article in English | MEDLINE | ID: mdl-25767119

ABSTRACT

Specific p53 mutations abrogate tumor-suppressive functions by gaining new abilities to promote tumorigenesis. Inactivation of p53 is known to distort TGF-ß signaling, which paradoxically displays both tumor-suppressive and pro-oncogenic functions. The molecular mechanisms of how mutant p53 simultaneously antagonizes the tumor-suppressive and synergizes the tumor-promoting function of the TGF-ß pathway remain elusive. Here we demonstrate that mutant p53 differentially regulates subsets of TGF-ß target genes by enhanced binding to the MH2 domain in Smad3 upon the integration of ERK signaling, therefore disrupting Smad3/Smad4 complex formation. Silencing Smad2, inhibition of ERK, or introducing a phosphorylation-defective mutation at Ser-392 in p53 abrogates the R175H mutant p53-dependent regulation of these TGF-ß target genes. Our study shows a mechanism to reconcile the seemingly contradictory observations that mutant p53 can both attenuate and cooperate with the TGF-ß pathway to promote cancer cell malignancy in the same cell type.


Subject(s)
Mutant Proteins/genetics , Mutant Proteins/metabolism , Mutation , Signal Transduction , Transforming Growth Factor beta/metabolism , Tumor Suppressor Protein p53/genetics , Tumor Suppressor Protein p53/metabolism , Animals , Cell Line, Tumor , Cell Movement , Extracellular Signal-Regulated MAP Kinases/metabolism , Gene Expression Regulation, Neoplastic , Humans , Lung Neoplasms/pathology , Mice , Smad2 Protein/metabolism , Smad3 Protein/metabolism , Snail Family Transcription Factors , Transcription Factors/metabolism , Transcription, Genetic
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