scholarly journals MiR-30a-5p alters epidermal terminal differentiation during aging by regulating BNIP3L/NIX-dependent mitophagy

2021 ◽  
Author(s):  
Fabien P CHEVALIER ◽  
Julie RORTEAU ◽  
Sandra FERRARO ◽  
Lisa S MARTIN ◽  
Alejandro GONZALEZ-TORRES ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Terminal Differentiation ◽  
Negative Regulator ◽  
Human Epidermis ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Primary Keratinocytes ◽  
Chronological Aging ◽  
Epidermal Homeostasis

Chronological aging is characterized by an alteration of the genes regulatory network. In human skin, epidermal keratinocytes fail to differentiate properly with aging, leading to the weakening of the epidermal function. MiR-30a is particularly overexpressed with epidermal aging, but the downstream molecular mechanisms are still uncovered. The aim of this study was to decipher the effects of miR-30a overexpression in the human epidermis, with a focus on keratinocyte differentiation. We formally identified the mitophagy receptor BNIP3L as a direct target of miR-30a. Using a 3D organotypic model of reconstructed human epidermis overexpressing miR-30a, we observed a strong reduction of BNIP3L expression in the granular layer. In human epidermal sections of skin biopsies from donors of different ages, we observed a similar pattern of BNIP3L decrease with aging. Moreover, human primary keratinocytes undergoing differentiation in vitro also showed a decreased expression of BNIP3L with age, together with a retention of mitochondria. Moreover, aging is associated with altered mitochondrial metabolism in primary keratinocytes, including decreased ATP-linked respiration. Thus, miR-30a is a negative regulator of programmed mitophagy during keratinocytes terminal differentiation, impairing epidermal homeostasis with aging.

scholarly journals Signal Transducer and Activator of Transcription 3 (STAT3) Suppresses STAT1/Interferon Signaling Pathway and Inflammation in Senescent Preadipocytes

Antioxidants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 334
Author(s):  
Aisha Y. Madani ◽  
Yasser Majeed ◽  
Houari B. Abdesselem ◽  
Maha V. Agha ◽  
Muneera Vakayil ◽  
...  
Keyword(s):  
Adipose Tissue ◽  
Molecular Mechanisms ◽  
Adenosine Monophosphate ◽  
Human Adipose Tissue ◽  
Premature Aging ◽  
Guanosine Monophosphate ◽  
Negative Regulator ◽  
Signal Transducer ◽  
Interferon Signaling

Obesity promotes premature aging and dysfunction of white adipose tissue (WAT) through the accumulation of cellular senescence. The senescent cells burden in WAT has been linked to inflammation, insulin-resistance (IR), and type 2 diabetes (T2D). There is limited knowledge about molecular mechanisms that sustain inflammation in obese states. Here, we describe a robust and physiologically relevant in vitro system to trigger senescence in mouse 3T3-L1 preadipocytes. By employing transcriptomics analyses, we discovered up-regulation of key pro-inflammatory molecules and activation of interferon/signal transducer and activator of transcription (STAT)1/3 signaling in senescent preadipocytes, and expression of downstream targets was induced in epididymal WAT of obese mice, and obese human adipose tissue. To test the relevance of STAT1/3 signaling to preadipocyte senescence, we used Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR associated protein 9 (CRISPR/Cas9) technology to delete STAT1/3 and discovered that STAT1 promoted growth arrest and cooperated with cyclic Guanosine Monophosphate-Adenosine Monophosphate (GMP-AMP) synthase-stimulator of interferon genes (cGAS-STING) to drive the expression of interferon β (IFNβ), C-X-C motif chemokine ligand 10 (CXCL10), and interferon signaling-related genes. In contrast, we discovered that STAT3 was a negative regulator of STAT1/cGAS-STING signaling—it suppressed senescence and inflammation. These data provide insights into how STAT1/STAT3 signaling coordinates senescence and inflammation through functional interactions with the cGAS/STING pathway.

scholarly journals CNPY4 inhibits the Hedgehog pathway by modulating membrane sterol lipids

2021 ◽  
Author(s):  
Megan Lo ◽  
Amnon Sharir ◽  
Michael D Paul ◽  
Hayarpi Torosyan ◽  
Christopher Agnew ◽  
...  
Keyword(s):  
Signal Transduction ◽  
Primary Cilia ◽  
Molecular Mechanisms ◽  
Negative Regulator ◽  
Membrane Composition ◽  
Hh Signaling ◽  
Pathway Regulation ◽  
Patched 1 ◽  
Cancer Signal Transduction

The Hedgehog (HH) pathway is critical for development and adult tissue homeostasis. Aberrant HH signaling can cause congenital malformations, such as digit anomalies and holoprosencephaly, and other diseases, including cancer. Signal transduction is initiated by HH ligand binding to the Patched 1 (PTCH1) receptor on primary cilia, thereby releasing inhibition of Smoothened (SMO), a HH pathway activator. Although cholesterol and several oxysterol lipids, which are enriched in the ciliary membrane, play a crucial role in HH activation, the molecular mechanisms governing the regulation of these lipid molecules remain unresolved. Here, we identify Canopy 4 (CNPY4), a Saposin-like protein, as a regulator of the HH pathway that controls membrane sterol lipid levels. Cnpy4—/— embryos exhibit multiple defects consistent with HH signaling perturbations, most notably changes in digit number. Knockdown of Cnpy4 hyperactivates the HH pathway at the level of SMO in vitro, and elevates membrane levels of accessible sterol lipids such as cholesterol, an endogenous ligand involved in SMO activation. Thus, our data demonstrate that CNPY4 is a negative regulator that fine-tunes the initial steps of HH signal transduction, revealing a previously undescribed facet of HH pathway regulation that operates through control of membrane composition.

Targeting MDM2-dependent serine metabolism as a therapeutic strategy for liposarcoma

2020 ◽  
Vol 12 (547) ◽  
pp. eaay2163
Author(s):  
Madi Y. Cissé ◽  
Samuel Pyrdziak ◽  
Nelly Firmin ◽  
Laurie Gayte ◽  
Maud Heuillet ◽  
...  
Keyword(s):  
Therapeutic Strategy ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Negative Regulator ◽  
Nucleotide Synthesis ◽  
Metabolic Functions ◽  
Xenograft Models ◽  
Well Differentiated ◽  
Serine Metabolism

Well-differentiated and dedifferentiated liposarcomas (LPSs) are characterized by a systematic amplification of the MDM2 oncogene, which encodes a key negative regulator of the p53 pathway. The molecular mechanisms underlying MDM2 overexpression while sparing wild-type p53 in LPS remain poorly understood. Here, we show that the p53-independent metabolic functions of chromatin-bound MDM2 are exacerbated in LPS and mediate an addiction to serine metabolism that sustains nucleotide synthesis and tumor growth. Treatment of LPS cells with Nutlin-3A, a pharmacological inhibitor of the MDM2-p53 interaction, stabilized p53 but unexpectedly enhanced MDM2-mediated control of serine metabolism by increasing its recruitment to chromatin, likely explaining the poor clinical efficacy of this class of MDM2 inhibitors. In contrast, genetic or pharmacological inhibition of chromatin-bound MDM2 by SP141, a distinct MDM2 inhibitor triggering its degradation, or interfering with de novo serine synthesis, impaired LPS growth both in vitro and in clinically relevant patient-derived xenograft models. Our data indicate that targeting MDM2 functions in serine metabolism represents a potential therapeutic strategy for LPS.

scholarly journals Antiphotoaging Effect of 3,5-Dicaffeoyl-epi-quinic Acid against UVA-Induced Skin Damage by Protecting Human Dermal Fibroblasts In Vitro

2020 ◽  
Vol 21 (20) ◽  
pp. 7756
Author(s):  
Jung Hwan Oh ◽  
Fatih Karadeniz ◽  
Chang-Suk Kong ◽  
Youngwan Seo
Keyword(s):  
Molecular Mechanisms ◽  
Type I Collagen ◽  
Nuclear Translocation ◽  
Quinic Acid ◽  
Dermal Fibroblasts ◽  
Type I ◽  
Human Dermal Fibroblasts ◽  
Skin Damage ◽  
Chronological Aging

Cutaneous aging is divided into intrinsic and exogenous aging correspondingly contributing to the complex biological phenomenon in skin. Intrinsic aging is also termed chronological aging, which is the accumulation of inevitable changes over time and is largely genetically determined. Superimposed on this intrinsic process, exogenous aging is associated with environmental exposure, mainly to ultraviolet (UV) radiation and more commonly termed as photoaging. UV-induced skin aging induces increased expression of matrix metalloproteinases (MMPs) which in turn causes the collagen degradation. Therefore, MMP inhibitors of natural origin are regarded as a primary approach to prevent or treat photoaging. This study investigated the effects of 3,5-dicaffeoyl-epi-quinic acid (DEQA) on photoaging and elucidated its molecular mechanisms in UVA-irradiated human dermal fibroblasts (HDFs). The results show that treatment with DEQA decreases MMP-1 production and increases type I collagen production in UVA-damaged HDFs. In addition, treatment of UVA-irradiated HDFs with DEQA downregulates MMP-1, MMP-3 and MMP-9 expression via blocking MAPK-cascade-regulated AP-1 transcriptional activity in UVA-irradiated HDFs. Furthermore, DEQA relieves the UVA-mediated suppression of type I procollagen and collagen expression through stimulating TGF-β/Smad signaling, leading to activation of the Smad 2/3 and Smad 4 nuclear translocation. These results suggest that DEQA could be a potential cosmetic agent for prevention and treatment of skin photoaging.

scholarly journals A protein phosphatase network controls the temporal and spatial dynamics of differentiation commitment in human epidermis

2017 ◽  
Author(s):  
Ajay Mishra ◽  
Angela Oliveira Pisco ◽  
Benedicte Oules ◽  
Tony Ly ◽  
Kifayathullah Liakath-Ali ◽  
...  
Keyword(s):  
Stem Cell ◽  
Terminal Differentiation ◽  
Human Keratinocytes ◽  
Cell Renewal ◽  
Stable States ◽  
Primary Human Keratinocytes ◽  
Network Modelling ◽  
Epidermal Homeostasis

AbstractEpidermal homeostasis depends on a balance between stem cell renewal and terminal differentiation1,2. While progress has been made in characterising the stem and differentiated cell compartments3, the transition between the two cell states, termed commitment4, is poorly understood. Here we characterise commitment by integrating transcriptomic and proteomic data from disaggregated primary human keratinocytes held in suspension for up to 12h. We have previously shown that commitment begins at approximately 4h and differentiation is initiated by 8h5. We find that cell detachment induces a network of protein phosphatases. The pro-commitment phosphatases – including DUSP6, PPTC7, PTPN1, PTPN13 and PPP3CA – promote terminal differentiation by negatively regulating ERK MAPK and positively regulating key API transcription factors. Their activity is antagonised by concomitant upregulation of the anti-commitment phosphatase DUSP10. The phosphatases form a dynamic network of transient positive and negative interactions, with DUSP6 predominating at commitment. Boolean network modelling identifies a mandatory switch between two stable states (stem cell and differentiated cell) via an unstable (committed) state. In addition phosphatase expression is spatially regulated relative to the location of stem cells, both in vivo and in response to topographical cues in vitro. We conclude that an auto-regulatory phosphatase network maintains epidermal homeostasis by controlling the onset and duration of commitment.

scholarly journals MiR-128-3p Post-Transcriptionally Inhibits WISP1 to Suppress Apoptosis and Inflammation in Human Articular Chondrocytes via the PI3K/AKT/NF-κB Signaling Pathway

2020 ◽  
Vol 29 ◽  
pp. 096368972093913
Author(s):  
Shujun Chen ◽  
Bo Li
Keyword(s):  
Signaling Pathway ◽  
Proinflammatory Cytokines ◽  
Molecular Mechanisms ◽  
Articular Chondrocytes ◽  
Negative Regulator ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Gene Assay ◽  
Induced Apoptosis

In osteoarthritis (OA), the synthesis and decomposition of the extracellular matrix (ECM) are imbalanced. High expression levels of Wnt1-inducible signaling pathway protein 1 (WISP1) promote the synthesis of matrix metalloproteinases and induce the degradation of cartilage, which aggravates the OA. The aim of this study was to explore the role of miR-128-3p in the development of OA. In the present study, the expression of WISP1 and miR-128-3p in osteoarthritic tissues and chondrocytes was detected using quantitative reverse transcription PCR (RT-qPCR) and Western blotting. Then we predicted that WISP1 might be a potential target gene of miR-128-3p by TargetScan and verified using luciferase reporter gene assay. The effect of miR-128-3p or WISP1 on chondrocytes was evaluated by cell proliferation assay, apoptosis, and caspase-3 activity assay. To further reveal the molecular mechanisms of miR-128-3p in osteoarthritic development, the degradation of chondrocyte matrix and production of proinflammatory cytokines in osteoarthritic chondrocyte model were detected by ELISA. To mimic the osteoarthritic microenvironment in vitro studies, chondrocytes were stimulated with interleukin (IL)-1β, and then we found that the expression of miR-128-3p was downregulated. Overexpression of WISP1 inhibited the proliferation of chondrocytes, which induced apoptosis, degradation of chondrocyte matrix, production of proinflammatory cytokines, and activated the phosphatidylinositol-3-kinase (PI3K)/protein kinase B (Akt)/nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) pathway. Then, we identified that miR-128-3p was a negative regulator of WISP1 by directly targeting its 3′-untranslated region (UTR). Moreover, the PI3K allosteric activator 740 Y-P abolished the inhibition of miR-128-3p in apoptosis, degradation of chondrocyte matrix, and inflammation. Our results showed that miR-128-3p targets WISP1 to regulate chondrocyte proliferation, apoptosis, degradation of chondrocyte matrix, and production of proinflammatory cytokines via the PI3K/Akt/NF-κB pathway, which plays a suppressed role in OA.

Protein composition of cornified cell envelopes of epidermal keratinocytes

1994 ◽  
Vol 107 (2) ◽  
pp. 693-700 ◽  
Author(s):  
A.C. Steven ◽  
P.M. Steinert
Keyword(s):  
Disulfide Bonds ◽  
Cell Envelope ◽  
Terminal Differentiation ◽  
Thick Layer ◽  
Protein Composition ◽  
Direct Methods ◽  
Epidermal Keratinocytes ◽  
Cystatin A ◽  
Cell Envelopes

Terminally differentiated mammalian epidermal cells are lined with a 15 nm thick layer of proteins cross-linked by isodipeptide and disulfide bonds, called the cornified cell envelope (CE). A number of proteins, including involucrin, loricrin, cystatin A, filaggrin, a cysteine-rich protein (CRP) and the ‘small proline-rich’ proteins (SPRRs) have been reported to be components of this complex, but little information has been obtained as to their relative abundances because the acute insolubility of the CEs has precluded direct methods of analysis. To address this question, we have determined the amino acid compositions of isolated CEs, and then modelled them in terms of linear combinations of the candidate proteins. The results show that stratum corneum CEs have a loricrin content of 65–70% (w/w) in human, and 80–85% in mouse. In human epidermal CEs, the secondary contributors are filaggrin and CRP (each approximately 10%), with smaller amounts of involucrin, SPRR and cystatin A (2-5% each) also present. Mouse epidermal CEs have about the same amount of filaggrin and somewhat more SPRR, but only trace amounts of the other proteins. In marked contrast, the major constituents of the CEs of cultured keratinocytes induced to terminal differentiation in vitro are cystatin A, involucrin and CRP (each approximately 30%). No significant amount of loricrin was detected except in sloughed mouse cells, which represent a more advanced state of terminal differentiation than attached cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Terminal differentiation in keratinocytes involves positive as well as negative regulation by retinoic acid receptors and retinoid X receptors at retinoid response elements

1992 ◽  
Vol 12 (11) ◽  
pp. 4862-4871
Author(s):  
B J Aneskievich ◽  
E Fuchs
Keyword(s):  
Retinoic Acid ◽  
Terminal Differentiation ◽  
Cell Types ◽  
Epidermal Differentiation ◽  
Retinoic Acid Receptors ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Retinoid X Receptors ◽  
Response Elements ◽  
X Receptors

Terminal differentiation of epidermal keratinocytes is inhibited by 1 microM retinoic acid, a concentration which induces differentiation in a number of cell types, including F9 teratocarcinoma cells. The molecular basis for these opposing retinoid responses is unknown, although retinoic acid receptors (RARs) and retinoid X receptors (RXRs) have been detected in both cell types. When F9 cells are stably transfected with a truncated RAR alpha lacking the E/F domain necessary for ligand binding and RAR/RXR dimerization, action at retinoid response elements is suppressed and cells produce a retinoic acid-resistant phenotype; i.e., they are blocked in differentiation (A. S. Espeseth, S. P. Murphy, and E. Linney, Genes Dev. 3:1647-1656, 1989). If retinoid receptors influence epidermal differentiation only in a negative fashion, then suppression of transactivation at retinoid response elements would be expected to enhance, rather than block, keratinocyte differentiation. In this study, we show that surprisingly, even though constitutive expression of an analogous truncated RAR gamma in keratinocytes specifically suppressed transactivation at retinoid response elements, keratinocytes were blocked, rather than enhanced, in their ability to undergo morphological and biochemical features of differentiation. These findings demonstrate a direct and hitherto unrecognized role for RARs and RXRs in positively as well as negatively regulating epidermal differentiation. Additionally, our studies extend those of Espeseth et al. (Genes Dev. 3:1647-1656, 1989), indicating a novel RAR function independent of the E/F domain.

scholarly journals Identification of Novel Keratinocyte Differentiation Modulating Compounds by High-Throughput Screening

2006 ◽  
Vol 11 (8) ◽  
pp. 977-984 ◽  
Author(s):  
Masaru Honma ◽  
Mark Stubbs ◽  
Ian Collins ◽  
Paul Workman ◽  
Wynne Aherne ◽  
...  
Keyword(s):  
Protein Kinase ◽  
High Throughput ◽  
High Throughput Screening ◽  
Histone Deacetylase Inhibitors ◽  
Terminal Differentiation ◽  
Mek Inhibitor ◽  
Keratinocyte Differentiation ◽  
Immunofluorescent Staining ◽  
Epidermal Keratinocytes ◽  
Human Epidermal Keratinocytes

The authors have designed high-throughput screens to identify compounds that promote or inhibit terminal differentiation of primary human epidermal keratinocytes. Eleven known inhibitors of signaling pathways and approximately 4000 compounds of diverse structure were screened using an In-Cell Western system based on immunofluorescent staining of the terminal differentiation marker, involucrin. Staurosporine, a nonspecific protein kinase C inhibitor, and H89, a protein kinase A inhibitor, promoted expression of involucrin. Conversely, U0126, a MEK inhibitor, and SAHA or SBHA, 2 histone deacetylase inhibitors, reduced the expression of involucrin during calcium-induced stratification. In addition, the authors found 1 novel compound that induced keratinocyte differentiation and 2 novel compounds that were inhibitory to calcium-induced differentiation. The differentiation-inducing compound also inhibited growth of a human squamous cell carcinoma line by stimulating both differentiation and apoptosis. Because the compound affected the tumor cells at a lower concentration than primary keratinocytes, it may have potential as an antitumor therapy.

scholarly journals The Phosphotransfer Protein CD1492 Represses Sporulation Initiation in Clostridium difficile

2016 ◽  
Vol 84 (12) ◽  
pp. 3434-3444 ◽  
Author(s):  
Kevin O. Childress ◽  
Adrianne N. Edwards ◽  
Kathryn L. Nawrocki ◽  
Sarah E. Anderson ◽  
Emily C. Woods ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Clostridium Difficile ◽  
Molecular Mechanisms ◽  
Toxin Production ◽  
Negative Regulator ◽  
Hamster Model ◽  
Content Type ◽  
Sporulation Initiation

The formation of spores is critical for the survival ofClostridium difficileoutside the host gastrointestinal tract. Persistence ofC. difficilespores greatly contributes to the spread ofC. difficileinfection (CDI), and the resistance of spores to antimicrobials facilitates the relapse of infection. Despite the importance of sporulation toC. difficilepathogenesis, the molecular mechanisms controlling spore formation are not well understood. The initiation of sporulation is known to be regulated through activation of the conserved transcription factor Spo0A. Multiple regulators influence Spo0A activation in other species; however, many of these factors are not conserved inC. difficileand few novel factors have been identified. Here, we investigated the function of a protein, CD1492, that is annotated as a kinase and was originally proposed to promote sporulation by directly phosphorylating Spo0A. We found that deletion ofCD1492resulted in increased sporulation, indicating that CD1492 is a negative regulator of sporulation. Accordingly, we observed increased transcription of Spo0A-dependent genes in theCD1492mutant. Deletion of CD1492 also resulted in decreased toxin productionin vitroand in decreased virulence in the hamster model of CDI. Further, theCD1492mutant demonstrated effects on gene expression that are not associated with Spo0A activation, including lowersigDandrstAtranscription, suggesting that this protein interacts with factors other than Spo0A. Altogether, the data indicate that CD1492 negatively affects sporulation and positively influences motility and virulence. These results provide further evidence thatC. difficilesporulation is regulated differently from that of other endospore-forming species.

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