Small Proline-Rich Protein 2A and 2D Are Regulated by the RBM38-p73 Axis and Associated with p73-Dependent Suppression of Chronic Inflammation

Small proline-rich protein 2A and 2D (SPRR2A and SPRR2D) provide barrier function in terminally differentiated stratified squamous epithelia through the epidermal differentiation complex. However, little is known how SPRR2A/2D expression is controlled and their role in chronic inflammation. Here, we showed that that SPRR2A/2D expression is controlled by a regulatory loop formed by RNA-binding protein RBM38 and tumor suppressor p73. Specifically, we found that SPRR2A/2D expression was induced by ectopic expression of RBM38 or p73 but suppressed by knockout of Rbm38 or p73. We also found that RBM38-mediated expression of SPRR2A/2D was p73-dependent and that induction of SPRR2A/2D during keratinocyte differentiation was dependent on both p73 and Rbm38. Additionally, we found that SPRR2A/2D expression was closely associated with p73 expression in normal and cancerous tissues. To determine the biological function of the RBM38-p73 loop potentially via SPRR2A/2D, we generated a cohort of wild-type, Rbm38−/−, Trp73+/−, and Rbm38−/−;Trp73+/− mice. We found that Rbm38−/−;Trp73+/− mice had a much shorter lifespan than that for Rbm38−/−—and to a lesser extent for Trp73+/− mice—but were less prone to spontaneous tumors than Trp73+/− or Rbm38−/− mice. We also found that Rbm38−/−;Trp73+/− mice exhibited weak expression of SPRR2A/2D in multiple tissues and were susceptible to systemic chronic inflammation, suggesting that decreased SPRR2A/2D expression is likely responsible for chronic inflammation in Rbm38−/−;Trp73+/− mice, leading to a shortened lifespan. Together, our data reveal that SPRR2A/2D are novel targets of the RBM38-p73 loop and contribute to p73-dependent suppression of chronic inflammation.

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The Effect of Single CpG Demethylation on the Pattern of DNA-Protein Binding

International Journal of Molecular Sciences ◽

10.3390/ijms20040914 ◽

2019 ◽

Vol 20 (4) ◽

pp. 914 ◽

Cited By ~ 1

Author(s):

Barbara Sobiak ◽

Wiesława Leśniak

Keyword(s):

Rna Binding ◽

Rna Binding Proteins ◽

Epidermal Differentiation ◽

Keratinocyte Differentiation ◽

Splicing Factors ◽

Targeted Next Generation Sequencing ◽

Factors Analysis ◽

Epidermal Differentiation Complex ◽

Complex Process ◽

Next Generation Sequencing Ngs

Epidermal differentiation is a complex process and its regulation may involve epigenetic factors. Analysis of DNA methylation in 20 selected regions within the epidermal differentiation complex (EDC) gene cluster by targeted next-generation sequencing (NGS) detected no or only minor changes in methylation, mostly slight demethylation, occurring during the course of keratinocyte differentiation. However, a single CpG pair within the exon of the PGLYRP3 gene underwent a pronounced demethylation concomitant with an increase in PGLYRP3 expression. We have employed a DNA-affinity precipitation assay (DAPA) and mass spectrometry to examine changes in the composition of proteins that bind to DNA containing either methylated or unmethylated CpG. We found that the unmethylated probe attracted mostly RNA binding proteins, including splicing factors, which suggests that demethylation of this particular CpG may facilitate PGLYRP3 transcription and/or pre-mRNA splicing.

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Single-cell transcriptomics defines keratinocyte differentiation in avian scutate scales

Scientific Reports ◽

10.1038/s41598-021-04082-1 ◽

2022 ◽

Vol 12 (1) ◽

Author(s):

Julia Lachner ◽

Florian Ehrlich ◽

Matthias Wielscher ◽

Matthias Farlik ◽

Marcela Hermann ◽

...

Keyword(s):

Gene Expression ◽

Single Cell ◽

Terminal Differentiation ◽

Epidermal Differentiation ◽

Keratinocyte Differentiation ◽

Epidermal Keratinocytes ◽

Scale Type ◽

Epidermal Differentiation Complex ◽

Evolutionarily Conserved ◽

Beta Proteins

AbstractThe growth of skin appendages, such as hair, feathers and scales, depends on terminal differentiation of epidermal keratinocytes. Here, we investigated keratinocyte differentiation in avian scutate scales. Cells were isolated from the skin on the legs of 1-day old chicks and subjected to single-cell transcriptomics. We identified two distinct populations of differentiated keratinocytes. The first population was characterized by mRNAs encoding cysteine-rich keratins and corneous beta-proteins (CBPs), also known as beta-keratins, of the scale type, indicating that these cells form hard scales. The second population of differentiated keratinocytes contained mRNAs encoding cysteine-poor keratins and keratinocyte-type CBPs, suggesting that these cells form the soft interscale epidermis. We raised an antibody against keratin 9-like cysteine-rich 2 (KRT9LC2), which is encoded by an mRNA enriched in the first keratinocyte population. Immunostaining confirmed expression of KRT9LC2 in the suprabasal epidermal layers of scutate scales but not in interscale epidermis. Keratinocyte differentiation in chicken leg skin resembled that in human skin with regard to the transcriptional upregulation of epidermal differentiation complex genes and genes involved in lipid metabolism and transport. In conclusion, this study defines gene expression programs that build scutate scales and interscale epidermis of birds and reveals evolutionarily conserved keratinocyte differentiation genes.

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A role for interleukin-1 in epidermal differentiation: regulation by expression of functional versus decoy receptors

Journal of Cell Science ◽

10.1242/jcs.108.8.2741 ◽

1995 ◽

Vol 108 (8) ◽

pp. 2741-2746 ◽

Cited By ~ 1

Author(s):

M.S. Eller ◽

M. Yaar ◽

K. Ostrom ◽

D.D. Harkness ◽

B.A. Gilchrest

Keyword(s):

Interleukin 1 ◽

Human Keratinocytes ◽

Cell Types ◽

Epidermal Differentiation ◽

Keratinocyte Differentiation ◽

Type I ◽

Type Ii ◽

Enhanced Expression ◽

Crabp Ii ◽

Small Proline Rich Protein

Although human epidermis contains levels of interleukin-1 (IL-1) up to 100 times higher than other tissues, the role of this cytokine in epidermal biology is unknown. Here, we show that interleukin-1 regulates the expression of mRNAs for two proteins associated with the differentiated phenotype of human keratinocytes, cellular retinoic acid-binding protein type II (CRABP II) and small, proline rich protein 1 (SPRR1). The ability of IL-1 to induce these transcripts correlates directly with keratinocyte expression of the IL-1 receptor type I (IL-1 RI) during differentiation and inversely with the expression of the type II IL-1 receptor (IL-1 RII), shown in other cell types to be a nonfunctional, decoy receptor. Furthermore, addition to keratinocyte cultures of an IL-1 RI-blocking, but not an IL-1 RII-blocking, antibody reduces the levels of CRABP II and SPRR1 mRNAs in these cells. These data suggest that epidermal IL-1 functions to promote keratinocyte differentiation and that a change in the IL-1 receptor profile of these cells initiates this IL-1 response through a relative enhanced expression of functional IL-1 receptors.

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The GEF Bcr activates RhoA/MAL signaling to promote keratinocyte differentiation via desmoglein-1

The Journal of Cell Biology ◽

10.1083/jcb.201304133 ◽

2013 ◽

Vol 202 (4) ◽

pp. 653-666 ◽

Cited By ~ 22

Author(s):

Adi D. Dubash ◽

Jennifer L. Koetsier ◽

Evangeline V. Amargo ◽

Nicole A. Najor ◽

Robert M. Harmon ◽

...

Keyword(s):

Rho Gtpases ◽

Adhesion Formation ◽

Ectopic Expression ◽

Epidermal Differentiation ◽

Keratinocyte Differentiation ◽

Nucleotide Exchange ◽

Rhoa Activity ◽

Guanine Nucleotide Exchange ◽

Nucleotide Exchange Factors ◽

Upstream Regulator

Although much is known about signaling factors downstream of Rho GTPases that contribute to epidermal differentiation, little is known about which upstream regulatory proteins (guanine nucleotide exchange factors [GEFs] or GTPase-activating proteins [GAPs]) are involved in coordinating Rho signaling in keratinocytes. Here we identify the GEF breakpoint cluster region (Bcr) as a major upstream regulator of RhoA activity, stress fibers, and focal adhesion formation in keratinocytes. Loss of Bcr reduced expression of multiple markers of differentiation (such as desmoglein-1 [Dsg1], keratin-1, and loricrin) and abrogated MAL/SRF signaling in differentiating keratinocytes. We further demonstrated that loss of Bcr or MAL reduced levels of Dsg1 mRNA in keratinocytes, and ectopic expression of Dsg1 rescued defects in differentiation seen upon loss of Bcr or MAL signaling. Taken together, these data identify the GEF Bcr as a regulator of RhoA/MAL signaling in keratinocytes, which in turn promotes differentiation through the desmosomal cadherin Dsg1.

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RNA-binding proteins La and HuR cooperatively modulate translation repression of PDCD4 mRNA

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014894 ◽

2020 ◽

pp. jbc.RA120.014894

Author(s):

Ravi Kumar ◽

Dipak Kumar Poria ◽

Partho Sarothi Ray

Keyword(s):

Inflammatory Response ◽

Chronic Inflammation ◽

Rna Binding ◽

Rna Binding Proteins ◽

Critical Role ◽

Regulation Of Gene Expression ◽

Mrna Translation ◽

Suppressor Gene ◽

Cooperative Action ◽

Translation Repression

Post-transcriptional regulation of gene expression plays a critical role in controlling the inflammatory response. An uncontrolled inflammatory response results in chronic inflammation, often leading to tumorigenesis. Programmed cell death 4 (PDCD4) is a pro-inflammatory tumor-suppressor gene which helps to prevent the transition from chronic inflammation to cancer. PDCD4 mRNA translation is regulated by an interplay between the oncogenic microRNA miR-21 and the RNA-binding protein (RBP) HuR in response to LPS stimulation, but the role of other regulatory factors remain unknown. Here we report that the RBP Lupus antigen (La) interacts with the 3’UTR of PDCD4 mRNA and prevents miR-21-mediated translation repression. While LPS causes nuclear-cytoplasmic translocation of HuR, it enhances cellular La expression. Remarkably, La and HuR were found to bind cooperatively to the PDCD4 mRNA and mitigate miR-21-mediated translation repression. The cooperative action of La and HuR reduced cell proliferation and enhanced apoptosis, reversing the pro-oncogenic function of miR-21. Together, these observations demonstrate a cooperative interplay between two RBPs, triggered differentially by the same stimulus, which exerts a synergistic effect on PDCD4 expression and thereby helps maintain a balance between inflammation and tumorigenesis.

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Selective sweep for an enhancer involucrin allele identifies skin barrier adaptation out of Africa

Nature Communications ◽

10.1038/s41467-021-22821-w ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Mary Elizabeth Mathyer ◽

Erin A. Brettmann ◽

Alina D. Schmidt ◽

Zane A. Goodwin ◽

Inez Y. Oh ◽

...

Keyword(s):

Selective Sweep ◽

Skin Barrier ◽

Human Migration ◽

Epidermal Differentiation ◽

Human Populations ◽

Epidermal Differentiation Complex ◽

Regulatory Module ◽

Reporter Assays ◽

Out Of Africa

AbstractThe genetic modules that contribute to human evolution are poorly understood. Here we investigate positive selection in the Epidermal Differentiation Complex locus for skin barrier adaptation in diverse HapMap human populations (CEU, JPT/CHB, and YRI). Using Composite of Multiple Signals and iSAFE, we identify selective sweeps for LCE1A-SMCP and involucrin (IVL) haplotypes associated with human migration out-of-Africa, reaching near fixation in European populations. CEU-IVL is associated with increased IVL expression and a known epidermis-specific enhancer. CRISPR/Cas9 deletion of the orthologous mouse enhancer in vivo reveals a functional requirement for the enhancer to regulate Ivl expression in cis. Reporter assays confirm increased regulatory and additive enhancer effects of CEU-specific polymorphisms identified at predicted IRF1 and NFIC binding sites in the IVL enhancer (rs4845327) and its promoter (rs1854779). Together, our results identify a selective sweep for a cis regulatory module for CEU-IVL, highlighting human skin barrier evolution for increased IVL expression out-of-Africa.

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Involvement of transcribed lncRNA uc.291 and SWI/SNF complex in cutaneous squamous cell carcinoma

Discover Oncology ◽

10.1007/s12672-021-00409-6 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

M. Mancini ◽

A. Cappello ◽

R. Pecorari ◽

A. M. Lena ◽

M. Montanaro ◽

...

Keyword(s):

Squamous Cell Carcinoma ◽

Cell Carcinoma ◽

Squamous Cell ◽

Expression Patterns ◽

Chromatin Accessibility ◽

Cutaneous Squamous Cell Carcinoma ◽

Epidermal Differentiation ◽

Differentiation Process ◽

Clinical Biomarkers ◽

Epidermal Differentiation Complex

AbstractWhile non-melanoma skin cancers (NMSCs) are the most common tumours in humans, only the sub-type cutaneous squamous cell carcinoma (cSCC), might become metastatic with high lethality. We have recently identified a regulatory pathway involving the lncRNA transcript uc.291 in controlling the expression of epidermal differentiation complex genes via the interaction with ACTL6A, a component of the chromatin remodelling complex SWI/SNF. Since transcribed ultra-conserved regions (T-UCRs) are expressed in normal tissues and are deregulated in tumorigenesis, here we hypothesize a potential role for dysregulation of this axis in cSCC, accounting for the de-differentiation process observed in aggressive poorly differentiated cutaneous carcinomas. We therefore analysed their expression patterns in human tumour biopsies at mRNA and protein levels. The results suggest that by altering chromatin accessibility of the epidermal differentiation complex genes, down-regulation of uc.291 and BRG1 expression contribute to the de-differentiation process seen in keratinocyte malignancy. This provides future direction for the identification of clinical biomarkers in cutaneous SCC. Analysis of publicly available data sets indicates that the above may also be a general feature for SCCs of different origins.

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