Potential of human γD-crystallin for hair damage repair : insights into the mechanical properties and biocompatibility

The objective of this work was to develop a new strategy to physically ‘repair’ chemically damaged hair. Hence the human eye γD-crystallin, a protein from the superfamily characterized structurally by the Greek key motif, was studied. The human γD-crystallin was chosen based on the ability of proteins belonging to this superfamily to be involved in the coating of specific structures. Two crystallins were used on the study, the wild type (Protein Data Bank ID: 1HK0) and the mutant protein. The mutant form was intended to induce a strong and quick protein polymerization as well to have new possible points of anchorage to hair.L'objectif de ce travail était de développer une nouvelle stratégie pour physiquement “réparer” les cheveux chimiquement endommagés. La protéine humaine γD-cristalline, une protéine de la superfamille caractérisée structurellement par le motif clé grecque, a été étudiée. Le γD-cristallin humain a été choisi en fonction de la capacité des protéines appartenant à cette superfamille d'être impliquées dans le revêtement des structures spécifiques. Deux cristallins ont été utilisés dans l'étude, le type sauvage (Protein Data Bank ID: 1HK0) et la protéine mutante. La forme mutante était destinée à induire une polymérisation de la protéine, forte et rapide ainsi d'avoir de nouveaux points d'ancrage possibles aux cheveux.This work is supported by FEDER through POFC-COMPETE and by national funds from FCT through the project PEst-C/BIA/UI4050/2011

Keratins and lipids in ethnic hair

Human hair has an important and undeniable relevance in society due to its important role in visual appearance and social communication. Hair is mainly composed of structural proteins, mainly keratin and keratin associated proteins, and lipids. Herein, we report a comprehensive study of the content and distribution of the lipids among ethnic hair, African, Asian and Caucasian hair. More interestingly, we also report the study of the interaction between those two main components of hair, specifically the influence of the hair internal lipids in the structure of the hair keratin. This was achieved by the use of a complete set of analytical tools such as thin layer chromatography-flame ionization detector, X-ray analysis, molecular dynamics simulation and confocal microscopy. The experimental results indicated different amounts of lipids on ethnic hair compositions and higher percentage of hair internal lipids in African hair. In this type of hair, the axial diffraction of keratin was not observed in X-ray analysis, but after hair lipids removal, the keratin returned to its typical packing arrangement. In molecular dynamic simulation lipids were shown to intercalate dimers of keratin, changing its structure. From those results we assume that keratin structure may be influenced by higher concentration of lipids in African hair.Margarida Fernandes held a PhD scholarship from Fundacaopara a Ciencia e Tecnologia (SFRH/BD/38 363/2007). The authors thank Vadim Volkov for the contribution with the confocal images

Effect of a peptide in cosmetic formulations for hair volume control

Objective The capacity of hair to absorb water causes changes in its physical and cosmetic properties under different environmental conditions. Hence, the control of hair volume in variable relative humidity settings is an important topic in cosmetics. The behaviour of two types of hair, Caucasian and Asian, was studied regarding their volume change in different relative humidity conditions. The ability of a peptide as a hair volume treatment was evaluated in two climate control formulations. Methods Tresses of the two types of hair were tested in two relative humidity (RH) conditions: (A) variable relative humidity (2 hours 40% RH, followed by 2 hours 90% RH and 2 hours of 40% RH), and (B) continuous high relative humidity (90% RH for 6 hours). Changes in the hair tress volume were assessed throughout time. Hair treated with two climate control formulations, with and without a peptide (KP peptide), were tested under the two relative humidity conditions. Results Caucasian hair had a higher change in volume compared to the Asian hair in variable and high relative humidity conditions. The hair volume increase when subject to high air humidity, and it was lower with the incorporation of a peptide into climate control formulations. Conclusion Caucasian hair showed higher volume than Asian hair when submitted to both relative humidity conditions. The incorporation of the peptide into the climate control formulations, a base (mostly composed of water 94%) and an ethanolic, was found to reduce the volume of Caucasian hair tresses. The presence of the peptide improved the hair volume change more than 60% in high relative humidity conditions.We thank the Industry and Processes Laboratory (LIP) from Centre of Biological Engineering (CEB) for allowing the use of the climate chamber Binder KBF 115. This work was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UID/BIO/04469/2013 unit and COMPETE 2020 (POCI01-0145-FEDER-006684) and under the Project RECI/BBB-EBI/ 0179/2012 (FCOMP-01-0124-FEDER-027462). This study was also supported by BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte2020 – Programa Operacional Regional do Norte. C elia F. Cruz and Artur Ribeiro thank FCT for SFRH/BD/ 100927/2014 and SFRH/BPD/98388/2013 grants, respectively.info:eu-repo/semantics/publishedVersio

Protein disulphide isomerase-mediated grafting of cysteine-containing peptides onto over-bleached hair

The ability of Protein disulphide isomerase (PDI) to promote the grafting of two cysteine-containing peptides onto hair was investigated in order to develop an alternative treatment for over-bleached hair. The studied peptides were designed based on human keratin and human lung surfactant proteins and were linked to a fluorescent dye to facilitate visualisation of the grafting process and to assess hair penetration. The ability of the peptides to restore mechanical and thermal properties lost by repeated bleaching treatments was also studied. After eight bleaching treatments, hair samples displayed 42% less mechanical resistance, coupled with a decrease in α-helix denaturation enthalpies and temperatures. Hair surface damage following bleaching was visualized by scanning electron microscopy. Addition of PDI to the treatment formulations promoted peptide attachment to the hair via disulphide bonds, facilitating their penetration into the hair cortex, as observed by fluorescence microscopy. The proposed peptide treatment resulted in an increase in α-helix denaturation enthalpy in over-bleached hair, as well as an increase in both Young's modulus and tensile strength. Thus, mechanical and thermal properties were improved after the peptide treatment in the presence of PDI; suggesting that the formulations presented in this work are promising candidates for hair-care applications

Protein disulphide isomerase-assisted functionalization of proteinaceous substrates

Protein disulphide isomerase (PDI) is an enzyme that catalyzes thiol-disulphide exchange reactions among a broad spectrum of substrates, including proteins and low-molecular thiols and disulphides. As the first protein-folding catalyst reported, the study of PDI has mainly involved the correct folding of several cysteine-containing proteins. Its application on the functionalization of protein-based materials has not been extensively reported. Herein, we review the applications of PDI on the modification of proteinaceous substrates and discuss its future potential. The mechanism involved in PDI functionalization of fibrous protein substrates is discussed in detail. These approaches allow innovative applications in textile dyeing and finishing, medical textiles, controlled drug delivery systems and hair or skin care products.We thank to FCT 'Fundacao para a Ciencia e Tecnologia' (scholarship SFRH/BD/38363/2007) for providing Margarida Fernandes the grant for PhD studies

Biology of human hair: Know your hair to control it

Hair can be engineered at different levels—its structure and surface—through modification of its constituent molecules, in particular proteins, but also the hair follicle (HF) can be genetically altered, in particular with the advent of siRNA-based applications. General aspects of hair biology are reviewed, as well as the most recent contributions to understanding hair pigmentation and the regulation of hair development. Focus will also be placed on the techniques developed specifically for delivering compounds of varying chemical nature to the HF, indicating methods for genetic/biochemical modulation of HF components for the treatment of hair diseases. Finally, hair fiber structure and chemical characteristics will be discussed as targets for keratin surface functionalization

Hair resistance to mechanical wear

Hair mechanical properties are primary indicators of hair integrity. Here we describe a methodology based on hair's resistance to mechanical wear to evaluate cosmetic treatments. Using a vibrational vortex cycle, we developed a protocol that relies on the plastic deformation and degradation of hair, due to frictional forces between hardened steel balls and hair fragments. We demonstrate that the balls when in contact with the hair fragments promoted extended hair degradation. The degree of degradation was related to hair's resistance to mechanical wear. Lower degradation rates reflect high resistance to mechanical wear. We found differences according to hair ethnicity and type of treatment. This methodology shows great potential for the screening and evaluation of the effect of cosmetic treatments on hair.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER000004) funded by the European Regional Development Fund under the scope of Norte 2020 - Programa Operacional Regional do Norte. AT thanks FTC for funding the scholarship with the reference SFRH/BD/114035/2015.info:eu-repo/semantics/publishedVersio

Different level of population differentiation among human genes

<p>Abstract</p> <p>Background</p> <p>During the colonization of the world, after dispersal out of African, modern humans encountered changeable environments and substantial phenotypic variations that involve diverse behaviors, lifestyles and cultures, were generated among the different modern human populations.</p> <p>Results</p> <p>Here, we study the level of population differentiation among different populations of human genes. Intriguingly, genes involved in osteoblast development were identified as being enriched with higher <it>F</it>_STSNPs, a result consistent with the proposed role of the skeletal system in accounting for variation among human populations. Genes involved in the development of hair follicles, where hair is produced, were also found to have higher levels of population differentiation, consistent with hair morphology being a distinctive trait among human populations. Other genes that showed higher levels of population differentiation include those involved in pigmentation, spermatid, nervous system and organ development, and some metabolic pathways, but few involved with the immune system. Disease-related genes demonstrate excessive SNPs with lower levels of population differentiation, probably due to purifying selection. Surprisingly, we find that Mendelian-disease genes appear to have a significant excessive of SNPs with high levels of population differentiation, possibly because the incidence and susceptibility of these diseases show differences among populations. As expected, microRNA regulated genes show lower levels of population differentiation due to purifying selection.</p> <p>Conclusion</p> <p>Our analysis demonstrates different level of population differentiation among human populations for different gene groups.</p

Mechanical analysis of infant carrying in hominoids

In all higher nonhuman primates, species survival depends upon safe carrying of infants clinging to body hair of adults. In this work, measurements of mechanical properties of ape hair (gibbon, orangutan, and gorilla) are presented, focusing on constraints for safe infant carrying. Results of hair tensile properties are shown to be species-dependent. Analysis of the mechanics of the mounting position, typical of heavier infant carrying among African apes, shows that both clinging and friction are necessary to carry heavy infants. As a consequence, a required relationship between infant weight, hair–hair friction coefficient, and body angle exists. The hair–hair friction coefficient is measured using natural ape skin samples, and dependence on load and humidity is analyzed. Numerical evaluation of the equilibrium constraint is in agreement with the knuckle-walking quadruped position of African apes. Bipedality is clearly incompatible with the usual clinging and mounting pattern of infant carrying, requiring a revision of models of hominization in relation to the divergence between apes and hominins. These results suggest that safe carrying of heavy infants justify the emergence of biped form of locomotion. Ways to test this possibility are foreseen here

Positive Selection in East Asians for an EDAR Allele that Enhances NF-κB Activation

Genome-wide scans for positive selection in humans provide a promising approach to establish links between genetic variants and adaptive phenotypes. From this approach, lists of hundreds of candidate genomic regions for positive selection have been assembled. These candidate regions are expected to contain variants that contribute to adaptive phenotypes, but few of these regions have been associated with phenotypic effects. Here we present evidence that a derived nonsynonymous substitution (370A) in EDAR, a gene involved in ectodermal development, was driven to high frequency in East Asia by positive selection prior to 10,000 years ago. With an in vitro transfection assay, we demonstrate that 370A enhances NF-κB activity. Our results suggest that 370A is a positively selected functional genetic variant that underlies an adaptive human phenotype