Peripheral blood gene expression profile of infants with atopic dermatitis

To enhance the understanding of molecular mechanisms and mine previously unidentified biomarkers of pediatric atopic dermatitis, PBMC gene expression profiles were generated by RNA sequencing in infants with atopic dermatitis and age-matched controls. A total of 178 significantly differentially expressed genes (DEGs) (115 upregulations and 63 downregulations) were seen, compared with those in healthy controls. The DEGs identified included IL1β, TNF, TREM1, IL18R1, and IL18RAP. DEGs were validated by real-time RT- qPCR in a larger number of samples from PBMCs of infants with atopic dermatitis aged <12 months. Using the DAVID (Database for Annotation, Visualization and Integrated Discovery) database, functional and pathway enrichment analyses of DEGs were performed. Gene ontology enrichment analysis showed that DEGs were associated with immune responses, inflammatory responses, regulation of immune responses, and platelet activation. Pathway analysis indicated that DEGs were enriched in cytokine‒cytokine receptor interaction, immunoregulatory interactions between lymphoid and nonlymphoid cells, hematopoietic cell lineage, phosphoinositide 3-kinase‒protein kinase B signaling pathway, NK cell‒mediated cytotoxicity, and platelet activation. Furthermore, the protein‒protein interaction network was predicted using the STRING (Search Tool for the Retrieval of Interacting Genes/Proteins) database and visualized with Cytoscape software. Finally, on the basis of the protein‒protein interaction network, 18 hub genes were selected, and two significant modules were obtained. In conclusion, this study sheds light on the molecular mechanisms of pediatric atopic dermatitis and may provide diagnostic biomarkers and therapeutic targets

Insulin-Like Growth Factor-Binding Protein 7 Regulates Keratinocyte Proliferation, Differentiation and Apoptosis

Insulin-like growth factor (IGF)-binding protein 7 (IGFBP7) belongs to the IGFBP superfamily, which is involved in the regulation of IGF and insulin signaling. Recently, a global gene expression study revealed that IGFBP7 is downregulated in the psoriatic epidermis, with UVB phototherapy restoring its expression to normal. In the present study, we confirmed that IGFBP7 expression is decreased in psoriatic lesions. Given the previous data suggesting a role for IGFBP7 in the control of cancer cell growth, we investigated its involvement in the regulation of keratinocyte (KC) proliferation and differentiation, which are abnormal in psoriasis. To model IGFBP7 downregulation in vitro, we used IGFBP7-specific small interfering RNA or small hairpin RNA-expressing lentiviral vectors in HaCaT cells or primary human KCs. Downregulation of IGFBP7 was found to markedly enhance KC proliferation in both systems, was associated with a significant decrease in KC susceptibility to tumor necrosis factor-α-induced apoptosis, but did not affect senescence. Downregulation of IGFBP7 was also shown to block expression of genes associated with calcium-induced differentiation of human KCs. Finally, recombinant IGFBP7 was found to inhibit KC proliferation and enhanced their apoptosis. These data position IGFBP7 as a regulator of KC proliferation and differentiation, suggesting a potential role for this protein in the pathophysiology and treatment of hyperproliferative dermatoses such as psoriasis

Insights into molecular mechanisms of disease in Neurodegeneration with Brain Iron Accumulation; unifying theories.

Neurodegeneration with brain iron accumulation (NBIA) is a group of disorders characterised by dystonia, parkinsonism and spasticity. Iron accumulates in the basal ganglia and may be accompanied by Lewy bodies, axonal swellings and hyperphosphorylated tau depending on NBIA subtype. Mutations in 10 genes have been associated with NBIA that include Ceruloplasmin (Cp) and Ferritin Light Chain (FTL), both directly involved in iron homeostasis, as well as Pantothenate Kinase 2 (PANK2), Phospholipase A2 group 6 (PLA2G6), Fatty acid hydroxylase 2 (FA2H), Coenzyme A synthase (COASY), C19orf12, WDR45 and DCAF17 (C2orf37). These genes are involved in seemingly unrelated cellular pathways, such as lipid metabolism, Coenzyme A synthesis and autophagy. A greater understanding of the cellular pathways that link these genes and the disease mechanisms leading to iron dyshomeostasis is needed. Additionally, the major overlap seen between NBIA and more common neurodegenerative diseases may highlight conserved disease processes. In this review, we will discuss clinical and pathological findings for each NBIA-related gene, discuss proposed disease mechanisms such as mitochondrial health, oxidative damage, autophagy/mitophagy and iron homeostasis and speculate potential overlap between NBIA subtypes

miRNA analysis of childhood atopic dermatitis reveals a role for miR-451a

BACKGROUND: MicroRNAs (miRNAs), important regulators of gene expression, have been implicated in a variety of disorders. The expression pattern of miRNAs in pediatric atopic dermatitis (AD) has not been well studied. OBJECTIVE: We sought to investigate miRNA expression profiles in different blood compartments of infants with AD. METHODS: Small RNA and HTG-Edge sequencing were performed to identify differentially expressed miRNAs in PBMCs and plasma of AD infants versus age-matched healthy controls, with reverse transcription quantitative real-time PCR used for validation and measurement of miRNA targets. Logistic regression models with AUROC estimation was used to evaluate the diagnostic potential of chosen miRNAs for AD. RESULTS: RNA sequencing was performed to access miRNA expression profile in pediatric AD. We identified ten differentially expressed miRNAs in PBMCs and eight dysregulated miRNAs in plasma of AD infants compared to controls. Upregulated miRNAs in PBMCs included miRNAs known to be involved in inflammation: miR-223-3p, miR-126-5p and miR-143-3p. Differential expression of only one miRNA, miR-451a, was observed in both PBMCs and plasma of children with AD. Dysregulation of three miRNAs: miR-451a, miR-143-3p and miR-223-3p was validated in larger number of samples and miR-451a was identified as a predictive biomarker for the early diagnosis of the disease. Experimentally verified targets of miR-451a, IL6R and PSMB8, were increased in AD patients, negatively correlated with miR-451a levels and upregulated following inhibition of miR-451a in PBMCs. CONCLUSION: In infants with AD, a distinct peripheral blood miRNA signature is seen, highlighting the systemic effects of the disease. miR-451a is uniquely expressed in different blood compartments of AD patients and may serve as a promising novel biomarker for the early diagnosis of AD

Mutations in SMARCAD1 cause autosomal dominant adermatoglyphia and perturb the expression of epidermal differentiation-associated genes

Autosomal dominant adermatoglyphia (ADG) is characterized by lack of palmoplantar epidermal ridges. Recently, ADG was found to be caused in one family by a mutation in SMARCAD1, a member of the SNF subfamily of the helicase protein superfamily.; To investigate the genetic basis of ADG.; We used direct sequencing and global gene expression analysis.; We identified three novel heterozygous mutations in SMARCAD1 (c.378 + 2T &gt; C, c.378 + 5G &gt; C and c.378 + 1G &gt; A) in a total of six patients. Surprisingly, all four ADG-causing mutations identified to date disrupt a single conserved donor splice site adjacent to the 3' end of a noncoding exon and are predicted to result in haploinsufficiency for a skin-specific isoform of SMARCAD1. These data indicate a pivotal role for the SMARCAD1-skin specific isoform in dermatoglyph formation. In order to better understand the consequences of ADG-associated mutations, we ascertained the global transcription profiles of primary keratinocytes downregulated for SMARCAD1 and of patient-derived keratinocytes. A total of eight genes were found to be differentially expressed in both patient-derived and knocked down keratinocytes. Of interest, these differentially expressed genes have been implicated in epidermal ontogenesis and differentiation, and in psoriasis, which is characterized by abnormal finger ridge patterns.; The present data suggest that ADG is genetically homogeneous and result from perturbed expression of epidermal differentiation-associated genes