Asymmetric Contribution of Blastomere Lineages of First Division of the Zygote to Entire Human Body Using Post-Zygotic Variants.

BACKGROUND: In humans, after fertilization, the zygote divides into two 2n diploid daughter blastomeres. During this division, DNA is replicated, and the remaining mutually exclusive genetic mutations in the genome of each cell are called post-zygotic variants. Using these somatic mutations, developmental lineages can be reconstructed. How these two blastomeres are contributing to the entire body is not yet identified. This study aims to evaluate the cellular contribution of two blastomeres of 2-cell embryos to the entire body in humans using post-zygotic variants based on whole genome sequencing. METHODS: Tissues from different anatomical areas were obtained from five donated cadavers for use in single-cell clonal expansion and bulk target sequencing. After conducting whole genome sequencing, computational analysis was applied to find the early embryonic mutations of each clone. We developed our in-house bioinformatics pipeline, and filtered variants using strict criteria, composed of mapping quality, base quality scores, depth, soft-clipped reads, and manual inspection, resulting in the construction of embryological phylogenetic cellular trees. RESULTS: Using our in-house pipeline for variant filtering, we could extract accurate true positive variants, and construct the embryological phylogenetic trees for each cadaver. We found that two daughter blastomeres, L1 and L2 (lineage 1 and 2, respectively), derived from the zygote, distribute unequally to the whole body at the clonal level. From bulk target sequencing data, we validated asymmetric contribution by means of the variant allele frequency of L1 and L2. The asymmetric contribution of L1 and L2 varied from person to person. CONCLUSION: We confirmed that there is asymmetric contribution of two daughter blastomeres from the first division of the zygote across the whole human body.

Restoration of Immune Privilege in Human Dermal Papillae Controlling Epithelial-Mesenchymal Interactions in Hair Formation.

BACKGROUND: Hair follicles are among a handful of organs that exhibit immune privilege. Dysfunction of the hair follicle immune system underlies the development of inflammatory diseases, such as alopecia areata. METHODS: Quantitative reverse transcription PCR and immunostaining was used to confirm the expression of major histocompatibility complex class I in human dermal papilla cells. Through transcriptomic analyses of human keratinocyte stem cells, major histocompatibility complex class I was identified as differentially expressed genes. Organ culture and patch assay were performed to assess the ability of WNT3a conditioned media to rescue immune privilege. Lastly, CD8+ T cells were detected near the hair bulb in alopecia areata patients through immunohistochemistry. RESULTS: Inflammatory factors such as tumor necrosis factor alpha and interferon gamma were verified to induce the expression of major histocompatibility complex class I proteins in dermal papilla cells. Additionally, loss of immune privilege of hair follicles was rescued following treatment with conditioned media from outer root sheath cells. Transcriptomic analyses found 58 up-regulated genes and 183 down-regulated genes related in MHC class I+ cells. Using newborn hair patch assay, we demonstrated that WNT3a conditioned media with epidermal growth factor can restore hair growth. In alopecia areata patients, CD8+ T cells were increased during the transition from mid-anagen to late catagen. CONCLUSION: Identification of mechanisms governing epithelial and mesenchymal interactions of the hair follicle facilitates an improved understanding of the regulation of hair follicle immune privilege.

Ectodysplasin-A2 induces dickkopf 1 expression in human balding dermal papilla cells overexpressing the ectodysplasin A2 receptor.

Androgenetic alopecia (AGA) is a common genetic disorder, and a X-chromosomal locus that contains the androgen receptor (AR) and ectodysplasin A2 receptor (EDA2R) genes represents a major susceptibility locus for AGA. In our previous study, we reported that ectodysplasin-A2 (EDA-A2) induces apoptosis in cultured human hair follicle (HF) cells and promotes the regression of HFs in mice. However, the role of the EDA-A2/EDA2R in AGA remains unknown, as the causative gene in this pathway has not yet been identified and potential functional connections between EDA-A2 signaling and the androgen pathway remain unclear. In this study, we investigated the expression of EDA2R in balding HFs and matched with non-balding HFs. The EDA2R level was upregulated in the balding dermal papilla (DP) cells compared with non-balding DP cells derived from patients with AGA. However, EDA2R was strongly expressed in both balding and non-balding outer root sheath (ORS) cells. We screened EDA-A2-regulated genes in balding DP cells and identified dickkopf 1 (DKK-1) as catagen inducer during the hair cycle. The mRNA and protein expression levels of DKK-1 were both upregulated by EDA-A2. In addition, DKK-1 expression was induced by EDA-A2 both in cultured human HFs and in mouse HFs. Moreover, the EDA-A2-induced apoptosis of DP and ORS cells was reversed by the antibody-mediated neutralization of DKK-1. Collectively, our data strongly suggest that EDA-A2 induces DKK-1 secretion and causes apoptosis in HFs by binding EDA2R, which is overexpressed in the bald scalp. EDA-A2/EDA2R signaling could inhibit hair growth through DKK-1 induction, and an inhibitor of EDA-A2/EDA2R signaling may be a promising agent for the treatment and prevention of AGA.

Particulate Matters Induce Apoptosis in Human Hair Follicular Keratinocytes.

BACKGROUND: Particulate matters (PM) comprise a heterogeneous mixture of particles suspended in air. A recent study found that urban PMs may penetrate into hair follicles via transfollicular and transdermal routes in dorsal skin. OBJECTIVE: To investigate the effects of PM on ex vivo cultured human scalp hair follicles and hair follicular keratinocytes in vitro. METHODS: TUNEL staining was employed to check cells undergoing apoptosis in cultured hair follicles after PM treatment. MTT assay was employed to check cell viability after PM treatment. Quantitative real-time PCR analysis was employed to quantitate the expression of inflammatory genes, matrix metalloproteinases (MMPs), and Duox1. Inflammatory cytokine levels were measured by ELISA after PM treatment. The level of reactive oxygen species (ROS) production was measured using a chemical fluorescent probe by a fluorescence plate reader. RESULTS: Abundant TUNEL-positive cells were observed in the keratinocyte region of hair including the epidermis, sebaceous gland, outer root sheath (ORS), inner root sheath (IRS), and bulb region. The viability of follicular cells, including the ORS, was found to be decreased upon PM exposure. mRNA expression and protein levels of inflammatory response genes and MMPs were upregulated in a dose-dependent manner by PM treatment. ROS levels were also increased by PM. CONCLUSION: These data strongly suggest that penetrated PMs from air pollution may cause apoptotic cell death to follicular keratinocytes by increased production of ROS and inflammatory cytokines, which could impair hair growth.

Expression pattern and intensity of protoporphyrin IX induced by liposomal 5-aminolevulinic acid in rat pilosebaceous unit throughout hair cycle.

We have developed liposomal formulation of 5-aminolevulinic acid (ALA) to enhance topical delivery and examined ALA-induced protoporpyrin (PpIX) expression in rat pilosebaceous unit throughout hair cycle. Two types of liposomes--glycerol dilaulate (GDL) and phosphatidylcholine (PC)--were formulated and both liposomal ALA increased PpIX expression in rat dorsal skin and pilosebaceous units when compared with free ALA. However, iontophoresis combined with liposomal ALA reduced the expression intensity of PpIX in hair bulbs although it achieved deeper and wider expression of PpIX through transfollicular pathway. After topical application in intact or depilated rat skin, liposomal ALA produced excellent PpIX expression in pilosebaceous units. The expression pattern and intensity of PpIX changed in hair cycle-dependent manner: specific expression only in sebaceous glands was observed at telogen; strong expression in whole pilosebaceous units was shown at anagen with intense expressions in hair bulbs and sebaceous glands; and a pattern similar to anagen but reduced intensity in the hair bulbs was seen at catagen. Throughout hair cycle, the expression pattern and intensity were dramatically changed in hair follicular epithelial cells depending on the cell density and proliferation activity of those cells, whereas those were consistent in sebaceous glands regardless of hair cycle. Little expression was shown in dermis. Photoactivation effect of 20% liposomal ALA-PDT using a red filtered-halogen lamp damaged sebaceous glands, hair follicles and epidermal layers. Formation of a thicker epidermal layer was observed, and hair induction after depilation was inhibited along with damage in sebaceous glands.

Liposome formulations for effective administration of lipophilic malonatoplatinum(II) complexes.

For effective administration of lipophilic trans(+/-)-1,2-diaminocyclohexaneplatinum(II) complexes of malonate derivatives [(dach)PtL, L=allylmalonate (AM), diallylmalonate (DAM), allylbenzylmalonate (ABM), or dibenzylmalonate (DBM)] in aqueous solution, we have applied three different liposome formulations and evaluated their physical and chemical properties, along with their in vitro cytotoxicity. The liposome formulations were composed of DMPC / DMPG [DMPC=1,2-dimyristoyl-sn-glycero-3-phosphocholine, DMPG=1,2-dimyristoyl-sn-glycero-3-(phospho-rac-1-glycerol) (sodium salt)] in different molar ratios (7/3 or 3/7) or an equimolar DOTAP/DOPE formulation (DOTAP=1,2-dioleoyl-3-trimethylammonium propane, DOPE=1,2-dioleoyl-sn-glycero-3-phosphoethanolamine). Preliposomal powders of the platinum complexes were prepared by lyophilization, and reconstituted in aqueous solution to obtain the final liposomal platinum complexes. Due to the lipophilicity of the malonatoplatinum complexes, the entrapment efficiency of drugs within the liposomes was over 90% except for the AM complex, and platinum drug stability was also satisfactory (>90%) in these liposomal systems. In vitro cytotoxicity was tested in human ovarian carcinoma cells sensitive (A2780) and resistant to cisplatin (A2780/PDD). In both cell lines, the liposomal DBM complex was much more cytotoxic than the corresponding DAM and ABM complexes, which means that the more hydrophobic benzyl substituent affords higher cytotoxicity than the allyl substituent in the malonato leaving group. Furthermore, the DBM complex in DMPC/DMPG formulations was effective against both sensitive and resistant A2780 cells (resistance indexes (RI)=1.10-1.49), showing lack of cross-resistance to cisplatin. Therefore, the liposomal DBM complex in the DMPC/DMPG formulations is a promising candidate for stable pharmaceutical liposomal platinum complexes.