Expression of a skin cholesterol sulfotransferase, St2b2, is a trigger of epidermal cell differentiation

Interaction of Native- and Oxidized-Low-Density Lipoprotein with Human Estrogen Sulfotransferase

Cytosolic estrogen sulfotransferase (SULT1E) mainly catalyzes the sulfate conjugation of estrogens, which decrease atherosclerosis progression. Recently we reported that a YKEG sequence in human SULT1E1 (hSULT1E1) corresponding to residues 61-64 can bind specifically to oxidized low-density lipoprotein (Ox-LDL), which plays a major role in the pathogenesis of atherosclerosis; its major oxidative lipid component lysophosphatidylcholine (LPC), and its structurally similar lipid, platelet-activating factor (PAF). In this study, we investigated the effect of Ox-LDL on the sulfating activity of hSULT1E1. In vivo experiments using a mouse model of atherosclerosis showed that the protein expression of SULT1E1 was higher in the aorta of mice with atherosclerosis compared with that in control animals. Results from a sulfating activity assay of hSULT1E1 using 1-hydroxypyrene as the substrate demonstrated that Ox-LDL, LPC, and PAF markedly decreased the sulfating activity of hSULT1E1, whereas native LDL and 1-palmitoyl-2-(5'-oxo-valeroyl)-sn-glycero-3-phosphocholine (POVPC) as one of the oxidized phosphatidylcholines showed the opposite effect. The sulfating activity greatly changed in the presence of LPC, PAF, and POVPC in their concentration-dependen manner (especially above their critical micelle concentrations). Moreover, Ox-LDL specifically recognized dimeric hSULT1E1. These results suggest that the effects of Ox-LDL and native LDL on the sulfating activity of hSULT1E1 might be helpful in elucidating the novel mechanism underlying the pathogenesis of atherosclerosis, involving the relationship between estrogen metabolism, LDL, and Ox-LDL.

Use of Topical Glycolic Acid Plus a Lovastatin-Cholesterol Combination Cream for the Treatment of Autosomal Recessive Congenital Ichthyoses

Importance

Autosomal recessive congenital ichthyosis (ARCI) is a heterogeneous group of disorders caused by defects in signaling pathways involved in epidermal proliferation and differentiation, leading to a wide range of skin manifestations. Therapeutic options are limited and often unsatisfactory. Topical cholesterol and statin as a combined formulation has proven successful in the treatment of patients with CHILD syndrome (congenital hemidysplasia ichthyosis and limb defects).

Objective

To assess change in disease severity score after a 3-month therapeutic regimen consisting of a glycolic acid, 10% to 20%, cream and a combination cream of lovastatin, 2%, with cholesterol, 2%, in the treatment of ARCI.

Design, Setting, and Participants

This case series of 15 patients with ARCI was conducted at the American University of Beirut, a referral center in the Middle East region for genodermatoses, between May 2017 and January 2018. No age groups were excluded; all patients were from the Middle East area; and all were initially not responsive to treatment with hydrating creams in combination with urea creams, 30% to 40%, or glycolic acid, 10% to 20%. Excluded were patients who had been taking systemic retinoids within 3 months before the start of the study.

Interventions

A 3-month therapeutic regimen of glycolic acid, 10% to 20%, cream and a combination of lovastatin, 2%, with cholesterol, 2%, cream.

Main Outcomes and Measures

Percentage change in disease severity scores following 2 and 3 months of study treatment.

Results

Of the 15 patients included in the study, 10 were male (mean age, 11.2 years; age range, 2-38 years). The average percentage reduction in the disease severity score was 33.7% at 2 months (from 60.8 to 40.2) and 57.5% at 3 months (from 60.8 to 21.9). Adverse effects were mild and consisted mainly of irritation and burning.

Conclusions and Relevance

These findings suggest a benefit from a treatment regimen consisting of glycolic acid, 10% to 20%, and a combination of lovastatin, 2%, with cholesterol, 2%, in the treatment of ARCI. This combination of creams might also prove to be beneficial in other types of ichthyoses and other dermatological diseases with a defective skin barrier.

X linked recessive ichthyosis: Current concepts

In the present review, we describe the most important aspects of the X-linked ichthyosis (XLI) and make a compilation of the some historic details of the disease. The aim of the present study is an update of the XLI. Historical, clinical, epidemiological, and molecular aspects are described through the text. Recessive XLI is a relatively common genodermatosis affecting different ethnic groups. With a high spectrum of the clinical manifestations due to environmental factors, the disease has a genetic heterogeneity that goes from a point mutation to a large deletion involving several genes to produce a contiguous gene syndrome. Most XLI patients harbor complete STS gene deletion and flanked sequences; seven intragenic deletions and 14 point mutations with a complete loss of the steroid sulfatase activity have been reported worldwide. In this study, we review current knowledge about the disease.

Role of cholesterol sulfate in epidermal structure and function: lessons from X-linked ichthyosis

X-linked ichthyosis is a relatively common syndromic form of ichthyosis most often due to deletions in the gene encoding the microsomal enzyme, steroid sulfatase, located on the short area of the X chromosome. Syndromic features are mild or unapparent unless contiguous genes are affected. In normal epidermis, cholesterol sulfate is generated by cholesterol sulfotransferase (SULT2B1b), but desulfated in the outer epidermis, together forming a 'cholesterol sulfate cycle' that potently regulates epidermal differentiation, barrier function and desquamation. In XLI, cholesterol sulfate levels my exceed 10% of total lipid mass (≈1% of total weight). Multiple cellular and biochemical processes contribute to the pathogenesis of the barrier abnormality and scaling phenotype in XLI. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.

SULT2B1: unique properties and characteristics of a hydroxysteroid sulfotransferase family

The SULT2b gene family consists of a single gene capable of generating two functional transcripts utilizing different transcriptional start sites in the first exon. This results in the translation of two separate proteins, SULT2B1a and SULT2B1b, with different amino-terminal peptides and approximately 95% identical sequences. The second distinguishing feature of the SULT2B isoforms is the proline/serine-rich carboxy-terminal sequence. To date, presence of the SULT2B gene appears limited to mammals and there is also only limited conservation of structure or sequence of the carboxy-terminal peptide. Although both SULT2B1 messages are present in human tissues, to date, only the SULT2B1b protein has been detected in the tissues investigated. In contrast, selective expression of SULT2B1a has been detected in rodent brain, whereas SULT2B1b was expressed in skin and intestine. Characterization of the SULT2B1 isoforms has been limited by the inability to isolate reliably active SULT2B1b from tissues or cells. SULT2B1 cDNAs can be expressed in Escherichia coli and the expressed active enzymes show selectivity for sulfation of 3β-hydroxysteroids. SULT2B1b due to the binding properties of the amino-terminal peptides also shows high cholesterol sulfation activity. Although human SULT2B1b displays significant substrate cross-reactivity with SULT2A1, the isoforms have different tissue expression patterns. Human SULT2B1b also shows nuclear localization in selected tissues that appears related to serine phosphorylation of the carboxy-terminal peptide. Overall, the understanding of the properties and function of the SULT2B1 isoforms is limited and the structural variability of the unique amino- and carboxy-sequences suggests significant species differences that need to be investigated.

Tumor necrosis factor-alpha-nuclear factor-kappa B-signaling enhances St2b2 expression during 12-O-tetradecanoylphorbol-13-acetate-induced epidermal hyperplasia

The mouse cholesterol sulfotransferase St2b2 contributes to epidermal differentiation by biosynthesizing cholesterol sulfate (CS) from cholesterol in the epidermis. 12-O-Tetradecanoylphorbol-13-acetate (TPA) causes epidermal hyperplasia, an abnormal increase in epidermal cell numbers resulting from aberrant cell differentiation and an increase in St2b2 protein levels. The mechanisms underlying enhanced St2b2 expression and the pathophysiologic significance of the increased expression are unclear, however. To verify whether increased St2b2 levels are necessary for TPA-induced epidermal hyperplasia, the effects of St2b2-specific small hairpin RNA (St2b2-shRNA) on hyperplasia were examined in mice. St2b2-shRNA clearly suppressed TPA-induced epidermal hyperplasia and the expression of a marker of epidermal differentiation, involucrin (INV). Interestingly, treating mouse epidermal cells with tumor necrosis factor-alpha (TNFα) increased St2b2 expression. Furthermore, treatment with TNFα-siRNA or anti-TNF receptor antibodies reduced the TPA-induced enhancement of St2b2 expression. Treatment with BAY 11-7082, a specific inhibitor of nuclear factor-kappa B (NF-κB), diminished TPA-induced St2b2 expression. These results suggested that enhancement of St2b2 expression by TPA treatment occurs mainly through the TNFα-NF-κB inflammatory signaling pathway, which in turn leads to increased CS concentrations in epidermal cells and hyperplasia.