scholarly journals A non-canonical lysosome biogenesis pathway generates Golgi-associated lysosomes during epidermal differentiation

2018 ◽  
Author(s):  
Sarmistha Mahanty ◽  
Shruthi Shirur Dakappa ◽  
Rezwan Shariff ◽  
Saloni Patel ◽  
Mruthyunjaya Mathapathi Swamy ◽  
...  
Keyword(s):  
Cellular Differentiation ◽  
Brefeldin A ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Differentiation Markers ◽  
Human Epidermal Keratinocytes ◽  
Lysosome Biogenesis ◽  
Proteome Changes ◽  
And Function

AbstractKeratinocytes maintain epidermis integrity and function including physical and antimicrobial barrier through cellular differentiation. This process is predicted to be controlled by calcium ion gradient and nutritional stress. Keratinocytes undergo proteome changes during differentiation, which enhances the intracellular organelle digestion to sustain the stress conditions. However, the molecular mechanism between epidermal differentiation and organelle homeostasis is poorly understood. Here, we used primary neonatal human epidermal keratinocytes to study the link between cellular differentiation, signaling pathways and organelle turnover. Upon addition of calcium chloride (2 mM) to the culture medium, keratinocytes increased their cell size and the expression of differentiation markers. Moreover, differentiated keratinocytes showed enhanced lysosome biogenesis that was dependent on ATF6-arm of UPR signaling but independent of mTOR-MiT/TFE transcription factors. Furthermore, chemical inhibition of mTOR has increased keratinocyte differentiation and relocalized the MiT/TFE TFs to the lysosome membranes, indicating that autophagy activation promotes the epidermal differentiation. Interestingly, differentiation of keratinocytes resulted in dispersal of fragmented Golgi and lysosomes, and the later organelles showed colocalization with Golgi-tethering proteins, suggesting that these lysosomes possibly originated from Golgi, hence named as Golgi-associated lysosomes (GALs). Consistent to this prediction, inhibition of Golgi function using brefeldin A completely abolished the formation of GALs and the keratinocyte differentiation. Thus, ER stress regulates the biogenesis of GALs, which maintains keratinocyte differentiation and epidermal homeostasis.

scholarly journals The role of cathepsin E in terminal differentiation of keratinocytes

2011 ◽  
Vol 392 (6) ◽  
Author(s):  
Tomoyo Kawakubo ◽  
Atsushi Yasukochi ◽  
Kuniaki Okamoto ◽  
Yoshiko Okamoto ◽  
Seiji Nakamura ◽  
...  
Keyword(s):  
Hair Follicle ◽  
Primary Cultures ◽  
Terminal Differentiation ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Marker Genes ◽  
Differentiation Markers ◽  
Cathepsin E

Abstract Cathepsin E (CatE) is predominantly expressed in the rapidly regenerating gastric mucosal cells and epidermal keratinocytes, in addition to the immune system cells. However, the role of CatE in these cells remains unclear. Here we report a crucial role of CatE in keratinocyte terminal differentiation. CatE deficiency in mice induces abnormal keratinocyte differentiation in the epidermis and hair follicle, characterized by the significant expansion of corium and the reduction of subcutaneous tissue and hair follicle. In a model of skin papillomas formed in three different genotypes of syngeneic mice, CatE deficiency results in significantly reduced expression and altered localization of the keratinocyte differentiation induced proteins, keratin 1 and loricrin. Involvement of CatE in the regulation of the expression of epidermal differentiation specific proteins was corroborated by in vitro studies with primary cultures of keratinocytes from the three different genotypes of mice. In wild-type keratinocytes after differentiation inducing stimuli, the CatE expression profile was compatible to those of the terminal differentiation marker genes tested. Overexpression of CatE in mice enhances the keratinocyte terminal differentiation process, whereas CatE deficiency results in delayed differentiation accompanying the reduced expression or the ectopic localization of the differentiation markers. Our findings suggest that in keratinocytes CatE is functionally linked to the expression of terminal differentiation markers, thereby regulating epidermis formation and homeostasis.

scholarly journals Identification of Axl as a downstream effector of TGF-β1 during Langerhans cell differentiation and epidermal homeostasis

2012 ◽  
Vol 209 (11) ◽  
pp. 2033-2047 ◽  
Author(s):  
Thomas Bauer ◽  
Anna Zagórska ◽  
Jennifer Jurkin ◽  
Nighat Yasmin ◽  
René Köffel ◽  
...  
Keyword(s):  
Transforming Growth Factor ◽  
Immune Cell ◽  
Inflammatory Responses ◽  
Apoptotic Cell ◽  
Skin Inflammation ◽  
Transforming Growth Factor Β1 ◽  
Epidermal Keratinocytes ◽  
Human Epidermal Keratinocytes ◽  
And Function ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1) is a fundamental regulator of immune cell development and function. In this study, we investigated the effects of TGF-β1 on the differentiation of human Langerhans cells (LCs) and identified Axl as a key TGF-β1 effector. Axl belongs to the TAM (Tyro3, Axl, and Mer) receptor tyrosine kinase family, whose members function as inhibitors of innate inflammatory responses in dendritic cells and are essential to the prevention of lupus-like autoimmunity. We found that Axl expression is induced by TGF-β1 during LC differentiation and that LC precursors acquire Axl early during differentiation. We also describe prominent steady-state expression as well as inflammation-induced activation of Axl in human epidermal keratinocytes and LCs. TGF-β1–induced Axl enhances apoptotic cell (AC) uptake and blocks proinflammatory cytokine production. The antiinflammatory role of Axl in the skin is reflected in a marked impairment of the LC network preceding spontaneous skin inflammation in mutant mice that lack all three TAM receptors. Our findings highlight the importance of constitutive Axl expression to tolerogenic barrier immunity in the epidermis and define a mechanism by which TGF-β1 enables silent homeostatic clearing of ACs to maintain long-term self-tolerance.

scholarly journals Pyridoxine Stimulates Filaggrin Production in Human Epidermal Keratinocytes

2021 ◽  
Author(s):  
Miyuki Fujishiro ◽  
Shoichi Yahagi ◽  
Shota Takemi ◽  
Takafumi Sakai ◽  
ichiro sakata
Keyword(s):  
Pyridoxal Phosphate ◽  
Seborrheic Dermatitis ◽  
Epidermal Differentiation ◽  
Disulfonic Acid ◽  
Epidermal Keratinocytes ◽  
Marker Genes ◽  
Dependent Manner ◽  
Human Epidermal Keratinocytes ◽  
Concentration Dependent Manner ◽  
Protein Levels

Abstract Pyridoxine (PN), one of the vitamers of vitamin B6, plays an important role in the maintenance of epidermal function and is used to treat acne and rough skin. Clinical studies have revealed that PN deficiency causes skin problems such as seborrheic dermatitis and stomatitis. However, the detailed effects of PN and its mechanism of action in epidermal function are poorly understood. In this study, we examined the effects of PN on epidermal function in normal human epidermal keratinocytes and found that PN specifically causes an increase in the expression of profilaggrin mRNA, among marker genes of terminal epidermal differentiation. In addition, PN treatment caused an increase in the production of filaggrin protein in a concentration-dependent manner. Treatment with P2x purinoceptor antagonists, namely, pyridoxal phosphate-6-azo (benzene-2,4-disulfonic acid) tetrasodium salt hydrate and TNP-ATP hydrate, induced an increase in the filaggrin protein levels. Moreover, we showed that elevated filaggrin production induced upon PN treatment was suppressed by ATP (known as P2x purinoceptor agonist). This study is the first to report that PN causes an increase in filaggrin transcription and production, and these results suggest that PN-induced filaggrin production may be a useful target as a daily care component in atopic dermatitis, wherein filaggrin levels are specifically reduced.

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 potency of the fs260 connexin43 mutant to impair keratinocyte differentiation is distinct from other disease-linked connexin43 mutants

2010 ◽  
Vol 429 (3) ◽  
pp. 473-483 ◽  
Author(s):  
Jared M. Churko ◽  
Stephanie Langlois ◽  
Xinyue Pan ◽  
Qing Shao ◽  
Dale W. Laird
Keyword(s):  
Endoplasmic Reticulum ◽  
Skin Disease ◽  
Disease Burden ◽  
Epidermal Differentiation ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Additive Effects ◽  
Wild Type ◽  
Organotypic Cultures ◽  
Oculodentodigital Dysplasia

Although there are currently 62 mutants of Cx43 (connexin43) that can cause ODDD (oculodentodigital dysplasia), only two mutants have also been reported to cause palmar plantar hyperkeratosis. To determine how mutants of Cx43 can lead to this skin disease, REKs (rat epidermal keratinocytes) were engineered to express an ODDD-associated Cx43 mutant always linked to skin disease (fs260), an ODDD-linked Cx43 mutant which has been reported to sometimes cause skin disease (fs230), Cx43 mutants which cause ODDD only (G21R, G138R), a mouse Cx43 mutant linked to ODDD (G60S), a non-disease-linked truncated Cx43 mutant that is trapped in the endoplasmic reticulum (Δ244*) or full-length Cx43. When grown in organotypic cultures, of all the mutants investigated, only the fs260-expressing REKs consistently developed a thinner stratum corneum and expressed lower levels of Cx43, Cx26 and loricrin in comparison with REKs overexpressing wild-type Cx43. REKs expressing the fs260 mutant also developed a larger organotypic vital layer after acetone-induced injury and exhibited characteristics of parakeratosis. Collectively, our results suggest that the increased skin disease burden exhibited in ODDD patients harbouring the fs260 mutant is probably due to multiple additive effects cause by the mutant during epidermal differentiation.

scholarly journals Differentiation-dependent changes in the solubility of a 195-kD protein in human epidermal keratinocytes.

1986 ◽  
Vol 103 (1) ◽  
pp. 41-48 ◽  
Author(s):  
A S Ma ◽  
T T Sun
Keyword(s):  
Human Keratinocytes ◽  
Epidermal Differentiation ◽  
Immunofluorescent Staining ◽  
Soluble Form ◽  
Epidermal Keratinocytes ◽  
Cell Periphery ◽  
Human Epidermal Keratinocytes ◽  
Intracellular Location ◽  
Differentiated Cells ◽  
Insoluble Form

We have prepared a monoclonal antibody, AE11, that recognizes specifically a 195-kD protein (pI 5.4) of human keratinocytes. This antigen constitutes approximately 0.01-0.1% of total protein in keratinocytes of skin, esophagus, and cornea, and is readily detectable in these cells by immunofluorescent staining and immunoblotting. However, it is barely detectable in MCF mammary carcinoma cells and HeLa cells, and is undetectable in nonepithelial cell types. Results from serial extraction experiments have shown that this protein exists in two distinct pools: a Tris-soluble, and a Tris-insoluble but urea- or SDS-soluble one. The distribution of the 195-kD protein between these two pools appears to be differentiation-related, since relatively undifferentiated cells selected by a low-calcium medium contain primarily the soluble form, while highly differentiated cells contain mainly the insoluble form. Data from immunofluorescent staining and trypsin-sensitivity experiments suggest that the soluble form is cytoplasmic, whereas the insoluble form is submembranously located at the cell periphery of upper, differentiated cells. The insoluble, cell peripheral form of the 195-kD antigen increases progressively during epidermal differentiation; its insolubility appears to be related to the formation of disulfide-bond(s). These results indicate that the 195-kD protein, which has recently been suggested to be involved in cornified envelope formation (Simon, M., and H. Green, 1985, Cell, 36:827-834), undergoes significant changes in its solubility characteristics and intracellular location during keratinocyte maturation.

scholarly journals Comparative Analysis of Cx31 and Cx43 in Differentiation-Competent Rodent Keratinocytes

Biomolecules ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1443
Author(s):  
Akina Au ◽  
Qing Shao ◽  
Kyra K. White ◽  
Sergiu A. Lucaciu ◽  
Jessica L. Esseltine ◽  
...  
Keyword(s):  
Gap Junctions ◽  
Protein Trafficking ◽  
Mrna Level ◽  
Brefeldin A ◽  
Time Lapse ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Single Cell Type ◽  
And Migration ◽  
Time Lapse Imaging

When considering connexin expression and regulation, the epidermis of the skin is one of the most complex tissues found in mammals even though it largely contains a single cell type, the keratinocyte. In the rodent epidermis, up to 9 connexin family members have been detected at the mRNA level. Many of these connexins are temporally and spatially regulated in coordination with keratinocyte progenitor cell differentiation and migration from the stratum basale to form the stratum spinosum and stratum granulosum layers before finally forming the stratum corneum. Cx43 is the principal connexin found in basal keratinocytes and to a lesser degree found in keratinocytes that have begun to differentiate where Cx26, Cx30 and Cx31 become prevalent. Here we show that the CRISPR-Cas9 ablation of Cx43 reduces overall gap junction coupling in monolayer cultures of rat epidermal keratinocytes (REKs) and dysregulates the differentiation of REKs when grown in organotypic cultures. Natively found in differentiated keratinocytes, Cx31 readily assembles into gap junctions when expressed in REKs where it can extensively co-assemble into the same gap junctions with co-expressed Cx30. Time-lapse imaging indicated that many Cx31 gap junctions are mobile within the plasma membrane undergoing both fusion and fission events. Finally, the persistence of pre-existing Cx31 gap junctions in the presence of the protein trafficking blocker, brefeldin A, is longer than that found for Cx43 gap junctions indicating that it has a distinctly different life expectancy in REKs. Collectively, this study highlights the importance of Cx43 in rodent keratinocyte differentiation and suggests that Cx31 acquires life-cycle properties that are distinct from Cx43.

scholarly journals Promoting effect of lactoferrin on barrier function and epithelial differentiation of human keratinocytes

2017 ◽  
Vol 95 (1) ◽  
pp. 64-68 ◽  
Author(s):  
Ryo Uchida ◽  
Reiji Aoki ◽  
Ayako Aoki-Yoshida ◽  
Atsushi Tajima ◽  
Yoshiharu Takayama
Keyword(s):  
P38 Mapk ◽  
Barrier Function ◽  
Regulatory Element ◽  
Human Keratinocytes ◽  
Epithelial Differentiation ◽  
Mitogen Activated Protein Kinase ◽  
Keratinocyte Differentiation ◽  
Epidermal Keratinocytes ◽  
Bovine Lactoferrin ◽  
Human Epidermal Keratinocytes

The purpose of this study was to elucidate the effects of bovine lactoferrin on keratinocyte differentiation and barrier function. Addition of bovine lactoferrin to differentiating HaCaT human keratinocytes led to increased transepithelial electrical resistance (TER), a marker of epithelial barrier function. This elevation was followed by upregulation of two differentiation markers, involucrin and filaggrin. The expression level of sterol regulatory element-binding protein-1 was also enhanced by bovine lactoferrin. The lactoferrin-induced upregulation of involucrin and filaggrin expression were confirmed in normal human epidermal keratinocytes (NHEK). Treatment with SB203580, a p38 mitogen-activated protein kinase (MAPK) α inhibitor, impaired the upregulation of involucrin and filaggrin expression in response to lactoferrin. The elevation of p38 MAPK phosphorylation was further enhanced by lactoferrin in the initial stage of differentiation of HaCaT keratinocytes. The findings suggest that bovine lactoferrin promotes epithelial differentiation by a p38-MAPK-dependent mechanism.

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