Skin Cornification Proteins Provide Global Link between ROS Detoxification and Cell Migration during Wound Healing

Wound healing is a complex dynamic process characterised by a uniform flow of events in nearly all types of tissue damage, from a small skin scratch to myocardial infarction. Reactive oxygen species (ROS) are essential during the healing process at multiple stages, ranging from the initial signal that instigates the immune response, to the triggering of intracellular redox-dependent signalling pathways and the defence against invading bacteria. Excessive ROS in the wound milieu nevertheless impedes new tissue formation. Here we identify small proline-rich (SPRR) proteins as essential players in this latter process, as they directly link ROS detoxification with cell migration. A literature-based meta-analysis revealed their up-regulation in various forms of tissue injury, ranging from heart infarction and commensal-induced gut responses to nerve regeneration and burn injury. Apparently, SPRR proteins have a far more widespread role in wound healing and tissue remodelling than their established function in skin cornification. It is inferred that SPRR proteins provide injured tissue with an efficient, finely tuneable antioxidant barrier specifically adapted to the tissue involved and the damage inflicted. Their recognition as novel cell protective proteins combining ROS detoxification with cell migration will provide new venues to study and manage tissue repair and wound healing at a molecular level

Aryl amino acetamides prevent Plasmodium falciparum ring development via targeting the lipid-transfer protein PfSTART1.

With resistance to most antimalarials increasing, it is imperative that new drugs are developed. We previously identified an aryl acetamide compound, MMV006833 (M-833), that inhibited the ring-stage development of newly invaded merozoites. Here, we select parasites resistant to M-833 and identify mutations in the START lipid transfer protein (PF3D7_0104200, PfSTART1). Introducing PfSTART1 mutations into wildtype parasites reproduces resistance to M-833 as well as to more potent analogues. PfSTART1 binding to the analogues is validated using organic solvent-based Proteome Integral Solubility Alteration (Solvent PISA) assays. Imaging of invading merozoites shows the inhibitors prevent the development of ring-stage parasites potentially by inhibiting the expansion of the encasing parasitophorous vacuole membrane. The PfSTART1-targeting compounds also block transmission to mosquitoes and with multiple stages of the parasite's lifecycle being affected, PfSTART1 represents a drug target with a new mechanism of action

Developmentally regulated epitopes on a neurofilament protein visualized by monoclonal antibodies.

Two monoclonal antibodies (mabs) which recognized the 68 kDa subunit of the rat neurofilament triplet were isolated. In immunoblots with SDS-solubilized and reduced proteins, these mabs recognized their epitopes equally well in embryonic and in adult tissue. However, these epitopes were developmentally regulated in paraformaldehyde-fixed rat brain sections. They were abundant in all compartments of differentiating neurons, whereas in mature neurons their presence was markedly attenuated, with a moderate abundance in perikarya and larger dendrites and low concentrations in axons. Thus, a differential developmental modification, possibly involving the masking of an epitope, is demonstrated for the small neurofilament polypeptide in rat and monkey brain tissue

Development

Integrins are ubiquitous transmembrane receptors that play crucial roles in cell-cell and cell-matrix interactions. In this study, we have determined the effects of the loss of beta1 integrins in keratinocytes in vitro and during cutaneous wound repair. Flow cytometry of cultured beta1-deficient keratinocytes confirmed the absence of beta1 integrins and showed downregulation of alpha6beta4 but not of alphanu integrins. beta1-null keratinocytes were characterised by poor adhesion to various substrates, by a reduced proliferation rate and by a strongly impaired migratory capacity. In vivo, the loss of 01 integrins in keratinocytes caused a severe defect in wound healing. beta1-null keratinocytes showed impaired migration and were more densely packed in the hyperproliferative epithelium. Surprisingly, their proliferation rate was not reduced in early wounds and even increased in late wounds. The failure in re-epithelialisation resulted in a prolonged inflammatory response, leading to dramatic alterations in the expression of important wound- regulated genes. Ultimately, beta1-deficient epidermis did cover the wound bed, but the epithelial architecture was abnormal. These findings demonstrate a crucial role of beta1 integrins in keratinocyte migration and wound re- epithelialisation

A crucial role of beta 1 integrins for keratinocyte migration in vitro and during cutaneous wound repair

Integrins are ubiquitous transmembrane receptors that play crucial roles in cell-cell and cell-matrix interactions. In this study, we have determined the effects of the loss of beta1 integrins in keratinocytes in vitro and during cutaneous wound repair. Flow cytometry of cultured beta1-deficient keratinocytes confirmed the absence of beta1 integrins and showed downregulation of alpha6beta4 but not of alphanu integrins. beta1-null keratinocytes were characterised by poor adhesion to various substrates, by a reduced proliferation rate and by a strongly impaired migratory capacity. In vivo, the loss of 01 integrins in keratinocytes caused a severe defect in wound healing. beta1-null keratinocytes showed impaired migration and were more densely packed in the hyperproliferative epithelium. Surprisingly, their proliferation rate was not reduced in early wounds and even increased in late wounds. The failure in re-epithelialisation resulted in a prolonged inflammatory response, leading to dramatic alterations in the expression of important wound- regulated genes. Ultimately, beta1-deficient epidermis did cover the wound bed, but the epithelial architecture was abnormal. These findings demonstrate a crucial role of beta1 integrins in keratinocyte migration and wound re- epithelialisation