Polymer Materials for Oral and Craniofacial Tissue Engineering
Vincenzo Guarino, Marco Antonio Alvarez-Pérez in Current Advances in Oral and Craniofacial Tissue Engineering, 2020
Keratin is a fibrous protein, found in hair, wool, feathers, nails and horns of mammals, reptiles and birds. Keratin proteins can be classified in intermediate filament proteins and the matrix proteins. The characteristic secondary structure of intermediate filaments is a-helix, also known as α-keratins and are low in sulfur content. The matrix proteins are globular, have high sulfur content and are surrounding the intermediate filament proteins interacting through disulfide bonds (Magin et al. 2007). Keratin is characterized by the presence of sequences as RGD (Arg-Gly-Asp) and LDV (Leu-Asp-Val) found in several ECM proteins for cell adhesion. Thus, keratin has been proposed as an alternative to collagen for developing biomaterials for tissue regeneration (Srinivasan et al. 2010). Besides, several studies have shown that the addition of keratin and adjusting its concentration, improved the mechanical properties of biomaterials (Zhang et al. 2014; Wang et al. 2015).
Cellular and Molecular Basis of Human Biology
Lawrence S. Chan, William C. Tang in Engineering-Medicine, 2019
Structural proteins are responsible for creating a functional frameworks of human structure and function, like muscles, tendon, bone, cartilage, skin, hair, nail, etc. Although the major skeletal muscle proteins include common contractile proteins of slow type 1 and fast types 2A and 2X myosins, actins, tropomyosins, troponin complexes, and metabolic proteins, there is a high variability in terms of relative composition since muscle protein types vary with age, activity type and level, and gender (Gelfi et al. 2011). In bone, about 90% of protein is in the form of type I collagen (Lammi et al. 2006). In cartilage, type II collagen and aggrecans (large aggregating chondroitin sulfate proteoglycan) predominate (Lammi et al. 2006). In tendon, the major proteins are type I (most abundant), II, and III collagens (Buckley et al. 2013). For the skin, collagen is one of the major protein components. Hair and nail proteins are primarily keratins.
Components of Nutrition
Christopher Cumo in Ancestral Diets and Nutrition, 2020
Proteins perform crucial functions. For example, insulin, mentioned earlier and having fifty-one amino acids, is the hormone that tells cells to admit glucose.69 In this way, insulin regulates the amounts of glucose inside and outside cells. Insulin also regulates glucose by telling the liver to store excess for release when the sugar becomes scarce in blood. Heme proteins, defined by the presence of iron (Fe), shuttle molecules and electrons throughout the body. Hemoglobin, a component of red blood cells, brings oxygen to cells and removes carbon dioxide for transport to the lungs. Carbon dioxide is a greenhouse gas, though human respiration emits little compared to factories and automobiles. The protein keratin helps form hair and skin. Proteins known as enzymes catalyze the body’s reactions. For example, enzymes pepsin and trypsin aid protein digestion by catalyzing cleavage of amino acid peptide bonds, mentioned earlier. Integral to the immune system, proteins that combat pathogens are known as antibodies. Attention has focused on the protein interferon, which targets viruses.
A review on proteomics analysis to reveal biological pathways and predictive proteins in sulfur mustard exposed patients: roles of inflammation and oxidative stress
Published in Inhalation Toxicology, 2019
Hojat Borna, Seyed Hojjat Hosseini Qale Noe, Asghar Beigi Harchegani, Nima Rahmani Talatappe, Mahdi Ghatrehsamani, Mostafa Ghanei, Alireza Shahriary
Keratins are the intermediate filaments-forming proteins which protect epithelial cell integrity against mechanical and non-mechanical stress (Coulombe & Omary, 2002). Previous studies showed the relationship between cytokeratins (CKs) expression and the regenerative or pathological status of the tracheobronchial epithelium in the lung (Iyonaga et al., 1997). Overexpression of CKs was found in lung biopsies of patients with idiopathic pulmonary fibrosis (Iyonaga et al., 1997). CKs are also highly expressed in different cancer types (Karantza, 2011). The effect of SM on keratin proteins within keratinocytes has also been studied. A proteomic based study on serum of SM exposed patients with chronic lung injury showed higher expression of CKs-1, -9 and -10 (Pashandi et al., 2015) (Table 1). In a proteome analysis study, increased breakdown of K14, K16 and K17 was observed in SM-exposed human keratinocyte cells at acute phase (Mol et al., 2008) (Table 1). Hess & FitzGerald (2007) revealed that SM can result in keratin filament destruction, leading to lysis of epidermal basal cells and skin blistering. Therefore, keratin overexpression may be a reason for altering tissues organization and injuries in SM exposed patients.
Berberine modulates Keratin 17 to inhibit cervical cancer cell viability and metastasis
Published in Journal of Receptors and Signal Transduction, 2021
Luping Liu, Li Sun, Jing Zheng, Li Cui
Keratin (KRT) is a protein family that is critical for hair formation and is the essential cellular structural material in forming the cornified layer which protects cells against damage or physical stress [10]. Keratin 17 (KRT17) is a kind of type I KRT [10], and upregulation of KRT17 expression is associated with lesion progression as well as poor prognosis in a number of epithelial cancers [11]. For example, overexpression of KRT17 was related to poor prognosis in epithelial ovarian cancer [12]. KRT17 performs an immunomodulatory function in skin by polarizing the immune response through up-regulating epithelial proliferation and tumor growth [13]. In addition, it is worth noting that an up-regulated KRT17 expression level was found in advanced cervical cancer tissue, and is closely associated with the poor survival of patients with this disease [14]. However, whether KRT17 could be regulated by BBR in cervical cancer cells remains elusive.
A novel technique to evaluate nail softening effects of different urea formulations
Published in Pharmaceutical Development and Technology, 2021
Hiep X. Nguyen, Yujin Kim, Tejas D. Kekatpure, Emily Lesica, Ajay K. Banga
Despite being a rigid and impermeable barrier, human nails could become soft and flexible after soaking in water. Hydration of nails was found to change the keratin structure and alter the physical properties of nails (Jemec et al. 1989). Nail hydration has been extensively studied using various techniques to provide valuable insights into the properties and behaviors of nails (Jemec et al. 1989; Nogueiras-Nieto et al. 2011; Chouhan and Saini 2012). In this study, after the hydration experiment, we observed swelling of the permeated area (0.2 sq.cm) of the membrane, which was absent from the untreated group. This study provided a qualitative comparison between different formulation groups regarding the appearance and color of the treated area. The swelling of the membrane could be attributed to the urea formulations in the donor chamber as well as its contact with the aqueous receptor fluid (10 mM PBS, pH 7.4) in the receptor compartment. We could identify a slight difference in the surface morphology and color of the treated area, however, failed to deliver reliable evidence to markedly distinguish a group from the other.
Related Knowledge Centers
- Epithelium
- Fibrous Protein
- Skin
- Alpha-Keratin
- Scale
- Hair
- Nail
- Horn
- Claw
- Hoof