Three stepwise pH progressions in stratum corneum for homeostatic maintenance of the skin.

The stratum corneum is the outermost skin layer with a vital role in skin barrier function. It is comprised of dead keratinocytes (corneocytes) and is known to maintain its thickness by shedding cells, although, the precise mechanisms that safeguard stratum corneum maturation and homeostasis remain unclear. Previous ex vivo studies have suggested a neutral-to-acidic pH gradient in the stratum corneum. Here, we use intravital pH imaging at single-corneocyte resolution to demonstrate that corneocytes actually undergo differentiation to develop three distinct zones in the stratum corneum, each with a distinct pH value. We identified a moderately acidic lower, an acidic middle, and a pH-neutral upper layer in the stratum corneum, with tight junctions playing a key role in their development. The upper pH neutral zone can adjust its pH according to the external environment and has a neutral pH under steady-state conditions owing to the influence of skin microbiota. The middle acidic pH zone provides a defensive barrier against pathogens. With mathematical modeling, we demonstrate the controlled protease activation of kallikrein-related peptidases on the stratum corneum surface that results in proper corneocyte shedding in desquamation. This work adds crucial information to our understanding of how stratum corneum homeostasis is maintained.

Genome-scale analysis of interactions between genetic perturbations and natural variation.

Interactions between genetic perturbations and segregating loci can cause perturbations to show different phenotypic effects across genetically distinct individuals. To study these interactions on a genome scale in many individuals, we used combinatorial DNA barcode sequencing to measure the fitness effects of 8046 CRISPRi perturbations targeting 1721 distinct genes in 169 yeast cross progeny (or segregants). We identified 460 genes whose perturbation has different effects across segregants. Several factors caused perturbations to show variable effects, including baseline segregant fitness, the mean effect of a perturbation across segregants, and interacting loci. We mapped 234 interacting loci and found four hub loci that interact with many different perturbations. Perturbations that interact with a given hub exhibit similar epistatic relationships with the hub and show enrichment for cellular processes that may mediate these interactions. These results suggest that an individual's response to perturbations is shaped by a network of perturbation-locus interactions that cannot be measured by approaches that examine perturbations or natural variation alone.

Summary of Research: An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: A Multicentre, Double-Blind, Placebo-Controlled Phase 2b Study.

This is a summary of the original article "An Anti-OX40 Antibody to Treat Moderate-to-Severe Atopic Dermatitis: a Multicentre, Double-blind, Placebo-Controlled Phase 2b Study". Atopic dermatitis (AD) is an inflammatory skin disease caused by a complex interplay of genetic factors, alterations to the skin microenvironment, and immune dysregulation, including T cells that have become uncontrolled. Rocatinlimab is an investigational agent that blocks OX40, a receptor on activated T cells that has an important role in inflammatory conditions such as AD. This summary of research provides an overview of a previously published article on the results of a phase 2b study of patients with moderate-to-severe AD who were treated with different doses of rocatinlimab or placebo and followed for up to 56 weeks. Rocatinlimab significantly improved the symptoms of AD and was well tolerated. The most common adverse events were fever, nasopharyngitis, and chills. This study supports rocatinlimab as a potentially safe and effective treatment for moderate-to-severe AD.

Morphological analysis of the human sperm tail during the early post-fertilization stage.

After fertilization, the human sperm tail lost its fibrous sheath at the pronuclear stage to become coiled and then attached to one of the first mitotic spindle poles. The tip of the sperm tail was branched and its degree did not change from the pronuclear stage to the second mitosis.

Genome-scale analysis of interactions between genetic perturbations and natural variation.

Interactions between genetic perturbations and segregating loci can cause perturbations to show different phenotypic effects across genetically distinct individuals. To study these interactions on a genome scale in many individuals, we used combinatorial DNA barcode sequencing to measure the fitness effects of 7,700 CRISPRi perturbations targeting 1,712 distinct genes in 169 yeast cross progeny (or segregants). We identified 460 genes whose perturbation has different effects across segregants. Several factors caused perturbations to show variable effects, including baseline segregant fitness, the mean effect of a perturbation across segregants, and interacting loci. We mapped 234 interacting loci and found four hub loci that interact with many different perturbations. Perturbations that interact with a given hub exhibit similar epistatic relationships with the hub and show enrichment for cellular processes that may mediate these interactions. These results suggest that an individual's response to perturbations is shaped by a network of perturbation-locus interactions that cannot be measured by approaches that examine perturbations or natural variation alone.

Epidermal Barrier Development via Corneoptosis: A Unique Form of Cell Death in Stratum Granulosum Cells.

Epidermal development is responsible for the formation of the outermost layer of the skin, the epidermis. The establishment of the epidermal barrier is a critical aspect of mammalian development. Proper formation of the epidermis, which is composed of stratified squamous epithelial cells, is essential for the survival of terrestrial vertebrates because it acts as a crucial protective barrier against external threats such as pathogens, toxins, and physical trauma. In mammals, epidermal development begins from the embryonic surface ectoderm, which gives rise to the basal layer of the epidermis. This layer undergoes a series of complex processes that lead to the formation of subsequent layers, including the stratum intermedium, stratum spinosum, stratum granulosum, and stratum corneum. The stratum corneum, which is the topmost layer of the epidermis, is formed by corneoptosis, a specialized form of cell death. This process involves the transformation of epidermal keratinocytes in the granular layer into flattened dead cells, which constitute the protective barrier. In this review, we focus on the intricate mechanisms that drive the development and establishment of the mammalian epidermis to gain insight into the complex processes that govern this vital biological system.

Keratinocytes of the Upper Epidermis and Isthmus of Hair Follicles Express Hemoglobin mRNA and Protein.

The epidermis, the keratinized stratified squamous epithelium surrounding the body surface, offers a valuable framework to investigate how terrestrial animals overcome environmental stresses. However, the mechanisms underlying epidermal barrier function remain nebulous. In this study, we examined genes highly expressed in the human and mouse upper epidermis, the outer frontier that induces various barrier-related genes. Transcriptome analysis revealed that the messenger RNA level of hemoglobin α (HBA), an oxygen carrier in erythroid cells, was enriched in the upper epidermis compared with that in the whole epidermis. Immunostaining analysis confirmed HBA protein expression in human and mouse keratinocytes (KCs) of the stratum spinosum and stratum granulosum. HBA was also expressed in hair follicle KCs in the isthmus region; its expression levels were more prominent than those in interfollicular KCs. HBA expression was not observed in noncutaneous keratinized stratified squamous epithelia of mice, for example, the vagina, esophagus, and forestomach. HBA expression was upregulated in human epidermal KC cultures after UV irradiation, a major cause of skin-specific oxidative stress. Furthermore, HBA knockdown increased UV-induced production of ROS in primary KCs. Our findings suggest that epidermal HBA expression is induced by oxidative stress and acts as an antioxidant, contributing to skin barrier function.

Kinetics of HBcrAg and HBsAg using highly sensitive iTACT assays in chronic hepatitis B patients with HBsAg seroclearance.

Two novel assays have been developed, iTACT-hepatitis B core-related antigen (iTACT-HBcrAg) and iTACT-hepatitis B surface antigen (iTACT-HBsAg) assays. We investigated the longitudinal profiles of iTACT-HBcrAg- and -HBsAg in patients with HBsAg seroclearance (SC) (<0.05 IU/mL). This study comprises 60 HBV-infected patients with HBsAg SC, 27 in chronic hepatitis/liver cirrhosis (CH/LC) group and 33 in inactive carrier (IC) group. Longitudinal profiles of iTACT-HBcrAg and -HBsAg were examined using stored serum samples. The median period from HBsAg SC to iTACT-HBcrAg loss or to the last observation was longer in the CH/LC group than the IC group (39 vs. -3 months, p = 0.004), but this tendency was not observed in that by iTACT-HBsAg. Comparing the times of iTACT-HBcrAg and -HBsAg loss, the rate of patients who lost HBcrAg first was significantly higher in the IC group (p = 0.008). The cumulative incidence rate of iTACT-HBcrAg loss after HBsAg SC was higher in the IC group that the CH/LC group (p = 0.002). Patients in the CH/LC group had higher rates of detectable iTACT-HBcrAg than those in the IC group after HBsAg SC, suggesting that the presence of HBcrAg possibly contribute to the progression of chronic hepatitis B.

Involvement of skin TRPV3 in temperature detection regulated by TMEM79 in mice.

TRPV3, a non-selective cation transient receptor potential (TRP) ion channel, is activated by warm temperatures. It is predominantly expressed in skin keratinocytes, and participates in various somatic processes. Previous studies have reported that thermosensation in mice lacking TRPV3 was impaired. Here, we identified a transmembrane protein, TMEM79, that acts as a negative regulator of TRPV3. Heterologous expression of TMEM79 was capable of suppressing TRPV3-mediated currents in HEK293T cells. In addition, TMEM79 modulated TRPV3 translocalization and promoted its degradation in the lysosomes. TRPV3-mediated currents and Ca2+ influx were potentiated in primary mouse keratinocytes lacking TMEM79. Furthermore, TMEM79-deficient male mice preferred a higher temperature than did wild-type mice due to elevated TRPV3 function. Our study revealed unique interactions between TRPV3 and TMEM79, both in vitro and in vivo. These findings support roles for TMEM79 and TRPV3 in thermosensation.

An anti-OX40 antibody to treat moderate-to-severe atopic dermatitis: a multicentre, double-blind, placebo-controlled phase 2b study.

BACKGROUND: OX40 is crucial for T-cell differentiation and memory induction. The anti-OX40 antibody, rocatinlimab inhibits the OX40 pathway. We evaluated the efficacy and safety of rocatinlimab in adults with moderate-to-severe atopic dermatitis. METHODS: This multicentre, double-blind, placebo-controlled phase 2b study was done at 65 secondary and tertiary sites in the USA, Canada, Japan, and Germany. Eligible patients were adults (aged 18 years or older) with confirmed atopic dermatitis (American Academy of Dermatology Consensus Criteria or local diagnostic criteria) with moderate-to-severe disease activity, as defined by an Eczema Area and Severity Index (EASI) score of 16 or more, validated Investigator's Global Assessment for Atopic Dermatitis score of 3 (moderate) or 4 (severe), and affected body surface area 10% or higher at both screening and baseline, with documented history (within 1 year) of inadequate response to topical medications or if topical treatments were medically inadvisable. Patients were randomly assigned (1:1:1:1:1) to receive subcutaneous rocatinlimab every 4 weeks (150 mg or 600 mg) or every 2 weeks (300 mg or 600 mg) or subcutaneous placebo up to week 18, with an 18-week active-treatment extension and 20-week follow-up. Percentage change from baseline in EASI score was assessed as the primary endpoint at week 16 and during the active extension and follow-up in all randomly assigned patients exposed to study drug with a post-baseline EASI score at week 16 or earlier according to the group they were randomly assigned to. Safety was assessed in all randomly assigned patients exposed to study drug; patients were analysed according to the group they were randomly assigned to. The study is registered with ClinicalTrials.gov, NCT03703102. FINDINGS: Between Oct 22, 2018, and Oct 21, 2019, 274 patients (114 [42%] women, 160 [58%] men; mean age 38·0 years [SD 14·5]) were randomly assigned to one of the rocatinlimab groups (217 [79%] patients) or to the placebo group (57 [21%] patients). Compared with placebo (-15·0 [95% CI -28·6 to -1·4]), significant least-squares mean percent reductions in EASI score at week 16 were observed in all rocatinlimab groups (rocatinlimab 150 mg every 4 weeks -48·3 [-62·2 to -34·0], p=0·0003; rocatinlimab 600 mg every 4 weeks -49·7 [-64·3 to -35·2], p=0·0002; rocatinlimab 300 mg every 2 weeks -61·1 [-75·2 to -47·0], p<0·0001; and rocatinlimab 600 mg every 2 weeks -57·4 [-71·3 to -43·4], p<0·0001). The most common adverse events during the double-blind period in patients receiving rocatinlimab (adverse events ≥5% of patients in the total rocatinlimab group and more common than the placebo group) were pyrexia (36 [17%] patients), nasopharyngitis (30 [14%] patients), chills (24 [11%] patients), headache (19 [9%] patients), aphthous ulcer (15 [7%] patients), and nausea (13 [6%] patients). There were no deaths. INTERPRETATION: Patients treated with rocatinlimab had progressive improvements in atopic dermatitis, which was maintained in most patients after treatment discontinuation. Treatment was well tolerated. FUNDING: Kyowa Kirin.

N-WASP-Arp2/3 signaling controls multiple steps of dendrite maturation in Purkinje cells in vivo.

During neural development, the actin filament network must be precisely regulated to form elaborate neurite structures. N-WASP tightly controls actin polymerization dynamics by activating an actin nucleator Arp2/3. However, the importance of N-WASP-Arp2/3 signaling in the assembly of neurite architecture in vivo has not been clarified. Here, we demonstrate that N-WASP-Arp2/3 signaling plays a crucial role in the maturation of cerebellar Purkinje cell (PC) dendrites in vivo in mice. N-WASP was expressed and activated in developing PCs. Inhibition of Arp2/3 and N-WASP from the beginning of dendrite formation severely disrupted the establishment of a single stem dendrite, which is a characteristic basic structure of PC dendrites. Inhibition of Arp2/3 after stem dendrite formation resulted in hypoplasia of the PC dendritic tree. Cdc42, an upstream activator of N-WASP, is required for N-WASP-Arp2/3 signaling-mediated PC dendrite maturation. In addition, overactivation of N-WASP is also detrimental to dendrite formation in PCs. These findings reveal that proper activation of N-WASP-Arp2/3 signaling is crucial for multiple steps of PC dendrite maturation in vivo.

Serum IL-1ß predicts de novo hepatitis B virus reactivation during direct-acting antiviral therapy for hepatitis C, not during anti-cancer/immunosuppressive therapy.

De novo hepatitis B virus (HBV) reactivation occurs during direct-acting antiviral (DAA) treatment in hepatitis C virus (HCV)-infected patients with resolved HBV infection. We evaluated the predictive factors, mechanical insight, and differences of cytokine levels during anti-cancer/immunosuppressive and DAA. Eleven, 35, and 19 HCV-infected patients with previous HBV infection with HBV reactivation during DAA treatment, previous HBV infection without HBV reactivation during DAA treatment, and without HBV infection resolution receiving DAA treatment, respectively, were enrolled. Clinical data and baseline cytokine levels were analyzed. Low baseline serum interleukin (IL)-1ß levels predicted de novo HBV reactivation during DAA treatment (odds ratio: 47.6, 95% confidence interval: 6.94-333.3). HCV-infected patients with the IL-1ß gene single nucleotide polymorphism rs16944 AA allele had significantly higher IL-1ß levels; no HCV-infected patient with the IL-1ß AA allele experienced HBV reactivation during DAA treatment. Compared to HCV-infected patients with HBV infection resolution, non-HCV infected patients with or without HBV reactivation during anti-cancer/immunosuppressive therapy or bone marrow transplantation had remarkably lower baseline IL-1ß levels. Low IL-1ß levels were not associated with HBV reactivation. IL-1ß levels before DAA for HCV-infected patients with resolved HBV infection could predict HBV reactivation during DAA treatment.

Energy-efficient production of vaccine protein against porcine edema disease from transgenic lettuce (Lactuca sativa L.).

The development of functional protein production systems using transgenic plants as hosts has been rapidly progressing in recent years. Lettuce (Lactuca sativa L.) has been studied as one such host, and it has been reported that the biomass of lettuce per area and target protein expression level can be increased by optimizing the cultivation conditions. Therefore, we investigated methods to minimize the input light energy per target protein to reduce production costs. Herein, we examined the yield of a nontoxic B subunit of Stx2e (Stx2eB) from transgenic lettuce under various cultivation conditions. Stx2eB acts as a vaccine against swine edema disease. The effects of photon flux densities (PPFDs), photoperiod, and light source on Stx2eB production were examined and the findings suggested that 400 µmol m-2 s-1, 24 h, and white LED lamps, respectively, contributed to energy-efficient Stx2eB production. In addition, Stx2eB was produced 1.4 times more efficiently per unit area time using a high plant density (228.5 plants m-2) than a common density (30.4 plants m-2). The findings of the present study can facilitate the development of energy-efficient and low-cost production processes for vaccine protein production, considering temporal and spatial perspectives.

Complex genetics cause and constrain fungal persistence in different parts of the mammalian body.

Determining how genetic polymorphisms enable certain fungi to persist in mammalian hosts can improve understanding of opportunistic fungal pathogenesis, a source of substantial human morbidity and mortality. We examined the genetic basis of fungal persistence in mice using a cross between a clinical isolate and the lab reference strain of the budding yeast Saccharomyces cerevisiae. Employing chromosomally encoded DNA barcodes, we tracked the relative abundances of 822 genotyped, haploid segregants in multiple organs over time and performed linkage mapping of their persistence in hosts. Detected loci showed a mix of general and antagonistically pleiotropic effects across organs. General loci showed similar effects across all organs, while antagonistically pleiotropic loci showed contrasting effects in the brain vs the kidneys, liver, and spleen. Persistence in an organ required both generally beneficial alleles and organ-appropriate pleiotropic alleles. This genetic architecture resulted in many segregants persisting in the brain or in nonbrain organs, but few segregants persisting in all organs. These results show complex combinations of genetic polymorphisms collectively cause and constrain fungal persistence in different parts of the mammalian body.

Microbiota-Independent Spontaneous Dermatitis Associated with Increased Sebaceous Lipid Production in Tmem79-Deficient Mice.

TMEM79 is a predisposing gene for atopic dermatitis. Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The first-phase dermatitis is unique because it occurs independent of microbiota status, whereas the second-phase dermatitis is microbiota dependent. In this study, we sought to identify the key factors mediating the development of first-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from first-phase dermatitis. Longitudinal RNA sequencing analysis revealed significant activation of fatty acid lipid metabolism pathways in first-phase dermatitis, whereas T helper 17‒based immune response genes were highly expressed in second-phase dermatitis. Quantitative RT-PCR analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in first-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 monounsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.

Increase in the Intracellular Bulk Water Content in the Early Phase of Cell Death of Keratinocytes, Corneoptosis, as Revealed by 65 GHz Near-Field CMOS Dielectric Sensor.

While bulk water and hydration water coexist in cells to support the expression of biological macromolecules, how the dynamics of water molecules, which have long been only a minor role in molecular biology research, relate to changes in cellular states such as cell death has hardly been explored so far due to the lack of evaluation techniques. In this study, we developed a high-precision measurement system that can discriminate bulk water content changes of ±0.02% (0.2 mg/cm3) with single-cell-level spatial resolution based on a near-field CMOS dielectric sensor operating at 65 GHz. We applied this system to evaluate the temporal changes in the bulk water content during the cell death process of keratinocytes, called corneoptosis, using isolated SG1 (first layer of stratum granulosum) cells in vitro. A significant irreversible increase in the bulk water content was observed approximately 1 h before membrane disruption during corneoptosis, which starts with cytoplasmic high Ca2+ signal. These findings suggest that the calcium flux may have a role in triggering the increase in the bulk water content in SG1 cells. Thus, our near-field CMOS dielectric sensor provides a valuable tool to dissect the involvement of water molecules in the various events that occur in the cell.

Novel electron microscopic staining method using traditional dye, hematoxylin.

Uranyl acetate (UA) has been routinely used as a staining solution for ultrathin sections used in biological electron microscopy. As a radioactive nuclear material, UA is subject to strict international regulations. To develop an alternative and easy-to-use staining method for ultrathin sections, we examined various commercial light microscopic dyes. We found that Mayer's hematoxylin followed by Reynold's lead citrate solution showed staining results comparable to UA and Reynold's lead citrate solution, and this method is therefore suggested as a reliable and promising alternative to UA staining.

The interplay of additivity, dominance, and epistasis on fitness in a diploid yeast cross.

In diploid species, genetic loci can show additive, dominance, and epistatic effects. To characterize the contributions of these different types of genetic effects to heritable traits, we use a double barcoding system to generate and phenotype a panel of ~200,000 diploid yeast strains that can be partitioned into hundreds of interrelated families. This experiment enables the detection of thousands of epistatic loci, many whose effects vary across families. Here, we show traits are largely specified by a small number of hub loci with major additive and dominance effects, and pervasive epistasis. Genetic background commonly influences both the additive and dominance effects of loci, with multiple modifiers typically involved. The most prominent dominance modifier in our data is the mating locus, which has no effect on its own. Our findings show that the interplay between additivity, dominance, and epistasis underlies a complex genotype-to-phenotype map in diploids.