RNA sequencing and lipidomics uncovers novel pathomechanisms in recessive X-linked ichthyosis

Recessive X-linked ichthyosis (RXLI), a genetic disorder caused by deletion or point mutations of the steroid sulfatase (STS) gene, is the second most common form of ichthyosis. It is a disorder of keratinocyte cholesterol sulfate retention and the mechanism of extracutaneous phenotypes such as corneal opacities and attention deficit hyperactivity disorder are poorly understood. To understand the pathomechanisms of RXLI, the transcriptome of differentiated primary keratinocytes with STS knockdown was sequenced. The results were validated in a stable knockdown model of STS, to confirm STS specificity, and in RXLI skin. The results show that there was significantly reduced expression of genes related to epidermal differentiation and lipid metabolism, including ceramide and sphingolipid synthesis. In addition, there was significant downregulation of aldehyde dehydrogenase family members and the oxytocin receptor which have been linked to corneal transparency and behavioural disorders respectively, both of which are extracutaneous phenotypes of RXLI. These data provide a greater understanding of the causative mechanisms of RXLI’s cutaneous phenotype, and show that the keratinocyte transcriptome and lipidomics can give novel insights into the phenotype of patients with RXLI

Loss of the laminin subunit alpha-3 induces cell invasion and macrophage infiltration in cutaneous squamous cell carcinoma

Background Cutaneous squamous cell carcinoma (cSCC) is a common cancer that invades the dermis through the basement membrane. The role of the basement membrane in poorly differentiated cSCC is not well understood.Objectives To study the effect that loss of the laminin subunit alpha-3 (alpha 3) chain from the tumour microenvironment has on tumour invasion and inflammatory cell recruitment.Methods We examined the role of the basement membrane proteins laminin subunits alpha 3, beta 3 and gamma 2 in SCC invasion and inflammatory cell recruitment using immunohistochemistry, short hairpin RNA knockdown, RNA-Seq, mouse xenograft models and patient tumour samples.Results Analysis of SCC tumours and cell lines using antibodies specific to laminin chains alpha 3, beta 3 and gamma 2 identified a link between poorly differentiated SCC and reduced expression of laminin alpha 3 but not the other laminin subunits investigated. Knockdown of laminin alpha 3 increased tumour invasion both in vitro and in vivo. Western blot and immunohistochemical staining identified increased phosphorylated myosin light chain with loss of laminin alpha 3. Inhibition of ROCK (rho-associated protein kinase) but not Rac1 significantly reduced the invasive potential of laminin alpha 3 knockdown cells. Knockdown of laminin subunits alpha 3 and gamma 2 increased monocyte recruitment to the tumour microenvironment. However, only the loss of laminin alpha 3 correlated with increased tumour-associated macrophages both in xenografted tumours and in patient tumour samples.Conclusions These data provide evidence that loss of the laminin alpha 3 chain in cSCC has an effect on both the epithelial and immune components of cSCC, resulting in an aggressive tumour microenvironment

A Human TREK-1/HEK Cell Line: A Highly Efficient Screening Tool for Drug Development in Neurological Diseases

TREK-1 potassium channels are involved in a number of physiopathological processes such as neuroprotection, pain and depression. Molecules able to open or to block these channels can be clinically important. Having a cell model for screening such molecules is of particular interest. Here, we describe the development of the first available cell line that constituvely expresses the TREK-1 channel. The TREK-1 channel expressed by the h-TREK-1/HEK cell line has conserved all its modulation properties. It is opened by stretch, pH, polyunsaturated fatty acids and by the neuroprotective molecule, riluzole and it is blocked by spadin or fluoxetine. We also demonstrate that the h-TREK-1/HEK cell line is protected against ischemia by using the oxygen-glucose deprivation model

Endo180 modulation by bisphosphonates and diagnostic accuracy in metastatic breast cancer

We thank the patients who participated in this study; Professor Gerry Thomas and the Imperial College Healthcare NHS Trust, Human Biomaterials Resource Centre (Tissue Bank); Professor Clare M Isacke (Institute of Cancer Research, London) for Endo180 antibodies; Dr Richard Harvey (Department of Medical Oncology, Imperial College Healthcare NHS Trust) for CA 15-3 antigen measurement. The Division of Cancer at Imperial College London, Imperial College Healthcare NHS Trust is an Experimental Cancer Medicine Centre (ECMC) supported by funds from Cancer Research UK and the Department of Health (C37/A7283) and forms part of Imperial Cancer Research UK Centre (C42671/A12196). CP is recipient of a CRUK Clinician Scientist award. JW is The Flow Foundation Professor of Oncology at Imperial College London. MPC and GK were supported by donations from Tony and Rita Gallagher and Imperial College NHS Healthcare Trust Special Trustees (to JW and JS). MPC was funded by The Rosetrees Trust (Grant JS16/M59; to JW and JS). A-VF was funded by Fundação para a Ciência e Tecnologia fellowship (project supervisor: JS) and Imperial College NHS Healthcare Special Trustees (to JW and JS). MR-T was funded by the Association of International Cancer Research (Grant 08-0803 to JS)

Shedding Light on The Role of Keratinocyte-Derived Extracellular Vesicles on Skin-Homing Cells

Extracellular vesicles (EVs) are secretory lipid membranes with the ability to regulate cellular functions by exchanging biological components between different cells. Resident skin cells such as keratinocytes, fibroblasts, melanocytes, and inflammatory cells can secrete different types of EVs depending on their biological state. These vesicles can influence the physiological properties and pathological processes of skin, such as pigmentation, cutaneous immunity, and wound healing. Since keratinocytes constitute the majority of skin cells, secreted EVs from these cells may alter the pathophysiological behavior of other skin cells. This paper reviews the contents of keratinocyte-derived EVs and their impact on fibroblasts, melanocytes, and immune cells to provide an insight for better understanding of the pathophysiological mechanisms of skin disorders and their use in related therapeutic approaches

Tumor-associated Endo180 requires stromal-derived LOX to promote metastatic prostate cancer cell migration on human ECM surfaces

The diverse composition and structure of extracellular matrix (ECM) interfaces encountered by tumor cells at secondary tissue sites can influence metastatic progression. Extensive in vitro and in vivo data has confirmed that metastasizing tumor cells can adopt different migratory modes in response to their microenvironment. Here we present a model that uses human stromal cell-derived matrices to demonstrate that plasticity in tumor cell movement is controlled by the tumor-associated collagen receptor Endo180 (CD280, CLEC13E, KIAA0709, MRC2, TEM9, uPARAP) and the crosslinking of collagen fibers by stromal-derived lysyl oxidase (LOX). Human osteoblast-derived and fibroblast-derived ECM supported a rounded ‘amoeboid-like’ mode of cell migration and enhanced Endo180 expression in three prostate cancer cell lines (PC3, VCaP, DU145). Genetic silencing of Endo180 reverted PC3 cells from their rounded mode of migration towards a bipolar ‘mesenchymal-like’ mode of migration and blocked their translocation on human fibroblast-derived and osteoblast-derived matrices. The concomitant decrease in PC3 cell migration and increase in Endo180 expression induced by stromal LOX inhibition indicates that the Endo180-dependent rounded mode of prostate cancer cell migration requires ECM crosslinking. In conclusion, this study introduces a realistic in vitro model for the study of metastatic prostate cancer cell plasticity and pinpoints the cooperation between tumor-associated Endo180 and the stiff microenvironment imposed by stromal-derived LOX as a potential target for limiting metastatic progression in prostate cancer