Further characterization of ATP6V0A2-related autosomal recessive cutis laxa.

Autosomal recessive cutis laxa (ARCL) syndromes are phenotypically overlapping, but genetically heterogeneous disorders. Mutations in the ATP6V0A2 gene were found to underlie both, autosomal recessive cutis laxa type 2 (ARCL2), Debré type, and wrinkly skin syndrome (WSS). The ATP6V0A2 gene encodes the a2 subunit of the V-type H(+)-ATPase, playing a role in proton translocation, and possibly also in membrane fusion. Here, we describe a highly variable phenotype in 13 patients with ARCL2, including the oldest affected individual described so far, who showed strikingly progressive dysmorphic features and heterotopic calcifications. In these individuals we identified 17 ATP6V0A2 mutations, 14 of which are novel. Furthermore, we demonstrate a localization of ATP6V0A2 at the Golgi-apparatus and a loss of the mutated ATP6V0A2 protein in patients' dermal fibroblasts. Investigation of brefeldin A-induced Golgi collapse in dermal fibroblasts as well as in HeLa cells deficient for ATP6V0A2 revealed a delay, which was absent in cells deficient for the ARCL-associated proteins GORAB or PYCR1. Furthermore, fibroblasts from patients with ATP6V0A2 mutations displayed elevated TGF-ß signalling and increased TGF-ß1 levels in the supernatant. Our current findings expand the genetic and phenotypic spectrum and suggest that, besides the known glycosylation defect, alterations in trafficking and signalling processes are potential key events in the pathogenesis of ATP6V0A2-related ARCL.

Multiple functions of LIM domain-binding CLIM/NLI/Ldb cofactors during zebrafish development.

The crucial involvement of CLIM/NLI/Ldb cofactors for the exertion of the biological activity of LIM homeodomain transcription factors (LIM-HD) has been demonstrated. In this paper we show that CLIM cofactors are widely expressed during zebrafish development with high protein levels in specific neuronal cell types where LIM-HD proteins of the Isl class are synthesized. The overexpression of a dominant-negative CLIM molecule (DN-CLIM) that contains the LIM interaction domain (LID) during early developmental stages of zebrafish embryos results in an impairment of eye and midbrain-hindbrain boundary (MHB) development and disturbances in the formation of the anterior midline. On a cellular level we show that the outgrowth of peripheral but not central axons from Rohon Beard (RB) and trigeminal sensory neurons is inhibited by DN-CLIM overexpression. We demonstrate a further critical role of CLIM cofactors for axonal outgrowth of motor neurons. Additionally, DN-CLIM overexpression causes an increase of Isl-protein expression levels in specific neuronal cell types, likely due to a protection of the DN-CLIM/LIM-HD complex from proteasomal degradation. Our results demonstrate multiple roles of the CLIM cofactor family for the development of entire organs, axonal outgrowth of specific neurons and protein expression levels.

Topically applied L-carnitine effectively reduces sebum secretion in human skin.

BACKGROUND: Oily skin condition is caused by an excessive sebaceous gland activity, resulting in an overproduction of sebum, giving the skin an undesired shiny, oily appearance. AIMS: To identify an active substance that reduces sebum production in human sebaceous glands by regulating fat metabolism in a natural way. PATIENTS/METHODS: The effects of L-carnitine on ß-oxidation and intracellular lipid content were investigated in vitro using the human sebaceous cell line SZ95. Penetration experiments utilizing pig skin as a model system were performed with a cosmetic formulation containing radioactively labeled L-carnitine. To determine the in vivo effects, a vehicle-controlled, randomized study was carried out using a cosmetic formulation containing 2%l-carnitine for 3 weeks. Sebum production was investigated utilizing the lipid-absorbent Sebutape(®). RESULTS: SZ95 cells treated with 0.5% or 1% L-carnitine demonstrated a significant concentration-dependent increase in ß-oxidation compared to control cells. Following the treatment with L-carnitine, intracellular lipid concentrations decreased significantly in a dose-dependent manner compared with untreated control cells. In skin penetration experiments, topically applied L-carnitine reached the dermis. In addition, topical in vivo application of a formulation containing 2% L-carnitine for 3 weeks significantly decreased the sebum secretion rate compared to the treatment with vehicle. CONCLUSIONS: Our results show that the treatment of human sebocytes with L-carnitine significantly augments ß-oxidation and significantly decreases intracellular lipid content in human sebocytes. Topically applied L-carnitine is bioavailable and leads to a significant sebum reduction in vivo. In conclusion, L-carnitine represents a valuable compound, produced naturally within the body, for the topical treatment of oily skin in humans.

Dermal penetration of creatine from a face-care formulation containing creatine, guarana and glycerol is linked to effective antiwrinkle and antisagging efficacy in male subjects.

BACKGROUND: The dermal extracellular matrix provides stability and structure to the skin. With increasing age, however, its major component collagen is subject to degeneration, resulting in a gradual decline in skin elasticity and progression of wrinkle formation. Previous studies suggest that the reduction in cellular energy contributes to the diminished synthesis of cutaneous collagen during aging. AIMS: To investigate the potential of topically applied creatine to improve the clinical signs of skin aging by stimulating dermal collagen synthesis in vitro and in vivo. PATIENTS/METHODS: Penetration experiments were performed with a pig skin ex vivo model. Effects of creatine on dermal collagen gene expression and procollagen synthesis were studied in vitro using cultured fibroblast-populated collagen gels. In a single-center, controlled study, 43 male Caucasians applied a face-care formulation containing creatine, guarana extract, and glycerol to determine its influence on facial topometric features. RESULTS: Cultured human dermal fibroblasts supplemented with creatine displayed a stimulation of collagen synthesis relative to untreated control cells both on the gene expression and at the protein level. In skin penetration experiments, topically applied creatine rapidly reached the dermis. In addition, topical in vivo application of a creatine-containing formulation for 6 weeks significantly reduced the sagging cheek intensity in the jowl area as compared to baseline. This result was confirmed by clinical live scoring, which also demonstrated a significant reduction in crow's feet wrinkles and wrinkles under the eyes. CONCLUSIONS: In summary, creatine represents a beneficial active ingredient for topical use in the prevention and treatment of human skin aging.

Ubiquitination-dependent cofactor exchange on LIM homeodomain transcription factors.

The interactions of distinct cofactor complexes with transcription factors are decisive determinants for the regulation of gene expression. Depending on the bound cofactor, transcription factors can have either repressing or transactivating activities. To allow a switch between these different states, regulated cofactor exchange has been proposed; however, little is known about the molecular mechanisms that are involved in this process. LIM homeodomain (LIM-HD) transcription factors associate with RLIM (RING finger LIM domain-binding protein) and with CLIM (cofactor of LIM-HD proteins; also known as NLI, Ldb and Chip) cofactors. The co-repressor RLIM inhibits the function of LIM-HD transcription factors, whereas interaction with CLIM proteins is important for the exertion of the biological activity conferred by LIM-HD transcription-factors. Here we identify RLIM as a ubiquitin protein ligase that is able to target CLIM cofactors for degradation through the 26S proteasome pathway. Furthermore, we demonstrate a ubiquitination-dependent association of RLIM with LIM-HD proteins in the presence of CLIM cofactors. Our data provide a mechanistic basis for cofactor exchange on DNA-bound transcription factors, and probably represent a general mechanism of transcriptional regulation.