Mice hair follicles (HFs) are a valuable model for studying various aspects of hair biology, including morphogenesis, development, and regeneration due to their easily observable phenotype and genetic manipulability. The initiation and progression of hair follicle morphogenesis, as well as the hair follicle cycle, are regulated by various signaling pathways, of which the main role is played by the Wingless-type MMTV integration site family (Wnt) and the Bone Morphogenic Protein (BMP). During the hair follicle cycle, the BMP pathway maintains hair follicle stem cells (HFSCs) in a dormant state while the Wnt pathway activates them for hair growth. Given the pivotal role of the Wnt pathway in hair biology and HFSCs regulation, we investigated the influence of the Wnt modulator - R-spondin 3 (Rspo3), in these processes. For this purpose, we developed a transgenic mice model with the overexpression of Rspo3 (Rspo3GOF) in the whole ectoderm and its derivatives, starting from early morphogenesis. Rspo3GOF mice exhibited a distinct phenotype with sparse hair and visible bald areas, caused by reduced proliferation and increased apoptosis of hair matrix progenitor cells, which resulted in a premature anagen-to-catagen transition with a shortened growth phase and decreased overall length of all hair types. In addition, Rspo3GOF promoted induction of auchene and awl, canonical Wnt-dependent hair type during morphogenesis, but the overall hair amount remained reduced. We also discovered a delay in the pre-bulge formation during morphogenesis and prolonged immaturity of the HFSC population in the bulge region postnatally, which further impaired proper hair regeneration throughout the mice’s lifespan. Our data supported that Rspo3 function observed in our model works in HFSCs’ formation of pre-bulge during morphogenesis via enhancing activation of the canonical Wnt pathway, whereas in contrast, in the postnatal immature bulge, activation of canonical Wnt signaling was attenuated. In vitro studies on keratinocytes revealed changes in proliferation, migration, and colony formation, highlighting the inhibitory effect of constitutive overexpression of Rspo3 on these cellular processes. Our research provides novel insights into the role of Rspo3 in the regulation of hair morphogenesis and development, along with the formation and maturation of the HFSCs, which affect hair regeneration.

α-catulin, together with vinculin and the α-catenins, belongs to the vinculin family of proteins, best known for their actin-filament binding properties and crucial roles in cell-cell and cell-substrate adhesion. In the past few years, an array of binding partners for α-catulin have surfaced, which has shed new light on the possible functions of this protein. Despite all this information, the molecular basis of how α-catulin acts in cells and controls a wide variety of signals during morphogenesis, tissue homeostasis, and cancer progression remains elusive. This review aims to highlight recent discoveries on how α-catulin is involved in a broad range of diverse biological processes with an emphasis on cancer progression.

Nails are highly keratinized skin appendages that exhibit continuous growth under physiological conditions and full regeneration upon removal. These mini-organs are maintained by two autonomous populations of skin stem cells. The fast-cycling, highly proliferative stem cells of the nail matrix (nail stem cells (NSCs)) predominantly replenish the nail plate. Furthermore, the slow-cycling population of the nail proximal fold (nail proximal fold stem cells (NPFSCs)) displays bifunctional properties by contributing to the peri-nail epidermis under the normal homeostasis and the nail structure upon injury. Here, we discuss nail mini-organ stem cells' location and their role in skin and nail homeostasis and regeneration, emphasizing their importance to orchestrate the whole digit tip regeneration. Such endogenous regeneration capabilities are observed in rodents and primates. However, they are limited to the region adjacent to the nail's proximal area, indicating the crucial role of nail mini-organ stem cells in digit restoration. Further, we explore the molecular characteristics of nail mini-organ stem cells and the critical role of the bone morphogenetic protein (BMP) and Wnt signaling pathways in homeostatic nail growth and digit restoration. Finally, we investigate the latest accomplishments in stimulating regenerative responses in regeneration-incompetent injuries. These pioneer results might open up new opportunities to overcome amputated mammalian digits and limbs' regenerative failures in the future.

The administration of Leu57-Leu58-His59-Lys60 (LLHK), Leu58-His59-Lys60 (LHK), and His59-Lys60 (HK) from β-lactoglobulin C variant, which is specific to Jersey cow milk, has been shown to prevent and/or restore the age-dependent atrophy and functional decline of salivary glands by affecting gene expression in elderly rats. In this study, we investigated the effect of Jersey cow defatted milk on salivary volume and composition in elderly persons. Participants (aged 85 to 98, n = 8) were administered defatted dry milk from Jersey cows twice a day for 4 weeks. Before and after 4 weeks from the start of drinking, saliva was collected and weighed. Salivary cystatin S and amylase levels were analyzed by Western blotting. To assess the effect of Jersey cow defatted milk on taste perception, questionnaires were used. Salivary volume after oral administration of 40 g of Jersey cow defatted dry milk daily for 4 weeks was 1.8 times higher than that before administration. Salivary cystatin S and amylase levels significantly increased after administration of Jersey cow defatted dry milk. Moreover, all participants who had taste impairment reported improved taste perception after administration. The administration of Jersey cow defatted dry milk increased salivary volume and changed the composition of saliva in elderly persons. Furthermore, it improved taste perception. J. Med. Invest. 68 : 280-285, August, 2021.

This article explores and summarizes recent progress in and the characterization of main players in the regulation and cyclic regeneration of hair follicles. The review discusses current views and discoveries on the molecular mechanisms that allow hair follicle stem cells (hfSCs) to synergistically integrate homeostasis during quiescence and activation. Discussion elaborates on a model that shows how different populations of skin stem cells coalesce intrinsic and extrinsic mechanisms, resulting in the maintenance of stemness and hair regenerative potential during an organism's lifespan. Primarily, we focus on the question of how the intrinsic oscillation of gene networks in hfSCs sense and respond to the surrounding niche environment. The review also investigates the existence of a cell-autonomous mechanism and the reciprocal interactions between molecular signaling axes in hfSCs and niche components, which demonstrates its critical driving force in either the activation of whole mini-organ regeneration or quiescent homeostasis maintenance. These exciting novel discoveries in skin stem cells and the surrounding niche components propose a model of the intrinsic stem cell oscillator which is potentially instructive for translational regenerative medicine. Further studies, deciphering of the distribution of molecular signals coupled with the nature of their oscillation within the stem cells and niche environments, may impact the speed and efficiency of various approaches that could stimulate the development of self-renewal and cell-based therapies for hair follicle stem cell regeneration.

Xerostomia, also known as dry mouth, is caused by a reduction in salivary secretion and by changes in the composition of saliva associated with the malfunction of salivary glands. Xerostomia decreases quality of life. In the present study, we investigated the effects of peptides derived from β-lactoglobulin C on age-dependent atrophy, gene expression profiles, and the dysfunction of salivary glands. Long-term oral administration of Leu57-Leu58-His59-Lys60 (LLHK), Leu58-His59-Lys60 (LHK) and His59-Lys60 (HK) peptides induced salivary secretion and prevented and/or reversed the age-dependent atrophy of salivary glands in older rats. The transcripts of 78 genes were upregulated and those of 81 genes were downregulated by more than 2.0-fold (p ≤ 0.05) after LHK treatment. LHK upregulated major salivary protein genes such as proline-rich proteins (Prpmp5, Prb3, Prp2, Prb1, Prp15), cystatins (Cst5, Cyss, Vegp2), amylases (Amy1a, Amy2a3), and lysozyme (Lyzl1), suggesting that LLHK, LHK, and HK restored normal salivary function. The AP-2 transcription factor gene (Tcfap2b) was also induced significantly by LHK treatment. These results suggest that LLHK, LHK, and HK-administration may prevent and/or reverse the age-dependent atrophy and functional decline of salivary glands by affecting gene expression.

Muscle damage in Duchenne muscular dystrophy (DMD), the incurable diseases caused by the lack of dystrophin, is strongly linked to inflammatory reactions. Accordingly, modulation of inflammation can ameliorate the disease progression. In our recent studies we have generated the double knockout (dKO) mdx mice lacking additionally either the active heme oxygenase-1 gene (HO-1, Hmox1) or miR-378a coding sequence. The HO-1 is the crucial anti-inflammatory protein affecting also muscle stem (satellite) cells differentiation, while miR-378a is involved in regulation of muscle differentiation and cellular metabolism. Lack of HO-1 aggravates the severity of DMD in a mdx mice and Hmox1-/-mdx dKO animals demonstrate strongly impaired exercise capacity. Interestingly, mdx satellite cells (SCs) show disturbed and enhanced differentiation, which is further aggravated by Hmox1 deficiency. Interestingly, mdx SCs expressed lower level of Hmox1, and RNA sequencing demonstrated the significant changes in mdx SCs transcriptome. Importantly, restoration of Hmox1 expression normalized the SCs differentiation. Surprisingly, mice lacking miR-378a were able to run longer distance than their wild-type (WT) in a treadmill test. Lack of miR-378a ameliorated the impairment characteristic for mdx mice, as 3-months old dKO animals were stronger than mdx mice and ran similar distance to WT. The muscles of dKO animals showed less infiltration of inflammatory cells. RNA-sequencing revealed the fibroblast growth factor 1 (Fgf1) among the most downregulated genes in animals lacking miR-378-/and in dKO mice, what might be of relevance to lower fibrosis observed in dKO than mdx mice In summary, HO-1 and miR-378a can be considered as targets to alleviate muscle injury and DMD severity.

Defective cellular trafficking of aquaporin-5 (AQP5) to the apical plasma membrane (APM) in salivary glands is associated with the loss of salivary fluid secretion. To examine mechanisms of α1-adrenoceptor (AR)-induced trafficking of AQP5, immunoconfocal microscopy and Western blot analysis were used to analyze AQP5 localization in parotid tissues stimulated with phenylephrine under different osmolality. Phenylephrine-induced trafficking of AQP5 to the APM and lateral plasma membrane (LPM) was mediated via the α1A-AR subtype, but not the α1B- and α1D-AR subtypes. Phenylephrine-induced trafficking of AQP5 was inhibited by ODQ and KT5823, inhibitors of nitric oxide (NO)-stimulated guanylcyclase (GC) and protein kinase (PK) G, respectively, indicating the involvement of the NO/ soluble (c) GC/PKG signaling pathway. Under isotonic conditions, phenylephrine-induced trafficking was inhibited by La3+, implying the participation of store-operated Ca2+ channel. Under hypotonic conditions, phenylephrine-induced trafficking of AQP5 to the APM was higher than that under isotonic conditions. Under non-stimulated conditions, hypotonicity-induced trafficking of AQP5 to the APM was inhibited by ruthenium red and La3+, suggesting the involvement of extracellular Ca2+ entry. Thus, α1A-AR activation induced the trafficking of AQP5 to the APM and LPM via the Ca2+/ cyclic guanosine monophosphate (cGMP)/PKG signaling pathway, which is associated with store-operated Ca2+ entry.

Salivary glands in elderly individuals commonly exhibit morphological changes and dysfunction resulting in xerostomia. Long-term (4-week) drinking of whey prevented and/or restored age-dependent decline of salivary volume and protein concentration, and atrophy of sublingual glands (SLGs) significantly in 88-week-old rats. The transcripts of 42 genes were up-regulated and 7 genes were down-regulated by more than 1.5-fold change with FDR ≤0.1 after whey-drinking. The expression levels of genes associated with salivary proteins and tissue repair were significantly increased, while those associated with lipid metabolism were decreased. Venn diagram analysis revealed that expressions of 13 genes, including Tcfap2b and Abpa, were induced significantly by whey-drinking. Furthermore, secretory protein levels in SLGs and saliva were revealed by immunoblot analysis. This is the first study to report that whey-administration can prevent and/or restore age-dependent atrophy and functional decline of SLGs in relation to gene expression and thus may serve as a functional food ingredient.

Background: saliva is useful to assess health or disease states. Recently, proteomic technologies have allowed rapid progress in saliva analysis.Highlight: (1) saliva contains three main types of extracellular vesicles; (2) the vesicles are exosomes, microvesicles, and apoptotic bodies; (3) proteome is analyzed in saliva, salivary exosomes, and salivary microvesicles; (4) membrane transporters are in saliva, and salivary exosomes and/or microvesicles; (5) biomarker discovery in exosomes and microvesicles of saliva is progressing.Conclusion: membrane transporters such as aquaporin, ion channels, carriers in saliva, and salivary exosomes or microvesicles, might be valuable biomarkers of systemic or oral health. (C) 2014 Japanese Association for Oral Biology. Published by Elsevier B.V.