Intracellular processing of endothelial nitric oxide synthase isoforms associated with differences in severity of cardiopulmonary diseases: cleavage of proteins with aspartate vs. glutamate at position 298

An endothelial nitric oxide synthase (eNOS) polymorphism in exon 7 (894 G/T) resulting in glutamate or aspartate, respectively, at position 298 on the protein is correlated with severity of cardiopulmonary diseases. Because glutamate and aspartate are considered to be conservative replacements, the polymorphism was thought to be a marker for a functional locus elsewhere in the gene. We now show in transfected cells, primary human endothelial cells, and human hearts, that eNOS with aspartate, but not glutamate, at position 298 is cleaved, resulting in the generation of 100-kDa and 35-kDa products. Recombinant or native eNOS was examined by immunoblotting either in lysates (COS7) or after partial purification over 2',5'-ADP-Sepharose and calmodulin-Sepharose. Immunoblotting after SDS/PAGE with a carboxyl-terminal antibody showed a single major protein band in the predicted position for eNOS at 135 kDa. An additional band at approximately 100 kDa was present only in the recombinant 298Asp eNOS and in the eNOS synthesized by primary cells and heart tissue with a G/T genotype. Using an eNOS amino-terminal-specific antibody, an immunoreactive band at approximately 35 kDa, corresponding to the residual N-terminal cleavage fragment, was observed in those cells with a T genotype. Thus, eNOS with aspartate but not glutamate at position 298 is cleaved, resulting in the generation of N-terminal 35-kDa and C-terminal 100-kDa fragments. Thus, the eNOS gene with polymorphisms at nucleotide 894 generates protein products with differing susceptibility to cleavage, suggesting that, in contrast to prior predictions, this polymorphism has a functional effect on the eNOS protein.

Endothelial nitric oxide synthase as a potential susceptibility gene in the pathogenesis of emphysema in alpha1-antitrypsin deficiency

A role for endothelial nitric oxide synthase (NOS3) in the susceptibility of individuals with alpha1-antitrypsin (alpha1AT) deficiency to destructive lung disease was evaluated. Six polymorphic sites were identified within the NOS3 gene (i.e., -924A/G, -788C/T, -691C/T, 774C/T, 894G/T, and 1998C/G). The genotype distribution was determined in 339 patients and 94 control individuals. Frequency of the 774T allele in severely affected individuals was 0.417 versus 0.269 in control subjects (P = 0.018), whereas the 894T allele frequency was 0.427 versus 0.280 in control subjects (P = 0.024). Patients with less severe lung disease had the 774T and 894T allele frequencies of 0.289 and 0.344, respectively, similar to frequencies in a control group (P > 0.3). No direct correlation between pulmonary function and five other NOS3 polymorphisms was observed. Thus, functional allelic variants that are in linkage disequilibrium with the 774C/T and 894G/T may be present in the specified genomic area. These data are consistent with a modulatory role for NOS3 in destructive lung disease associated with alpha1AT deficiency.

Relationship between stress protein induction in rat kidney by mercuric chloride and nephrotoxicity

Adverse environmental stimuli increase the synthesis of a class of proteins referred to as stress proteins. The effect of mercuric chloride, a model nephrotoxin, on protein synthesis in male rat kidney has been evaluated. Renal slices from exposed rats were incubated with [35S]methionine for 1 hr and subjected to SDS-PAGE, after which 35S-labeled proteins were detected by autoradiography. Enhanced de novo synthesis of 70- and 90-kDa relative molecular mass (M(r)) proteins were detected 2 hr after exposure to 1 mg Hg/kg, with maximum activity occurring at 4-8 hr. By 16 hr postinjection, synthesis of these two proteins had decreased. Dose-related increases in synthesis of these proteins, and of a 110-kDa protein, were observed 4 hr after i.v. injection of 0.25, 0.5, and 1.0 mg Hg/kg, with concomitant inhibition of synthesis of proteins of M(r) 38 and 68 kDa. At a dose of 1 mg/kg, kidney proximal tubules exhibited progressive degenerative changes from 4 to 24 hr. A functional deficit, decreased uptake of [para-3H]aminohippurate into renal slices, was not observed until 16 hr after i.v. injection of 1 mg/kg. No significant histopathologic changes were observed in kidneys 4 hr after treatment with 0.25 or 0.5 mg Hg/kg, iv. No changes in liver protein synthesis were apparent until 16-24 hr, where an increase in the 70- and 90-kDa proteins was observed. A concomitant increase in plasma sorbitol dehydrogenase activity occurred at 16-24 hr; however, there was no histopathological evidence of liver injury. The 72-kDa inducible member of the 70-kDa stress protein family and the 88-kDa member of the 90-kDa protein family were detected by immunoblotting techniques using monoclonal antibodies. The data demonstrate that Hg induces alterations in the expression of renal gene products in vivo as evidenced by enhanced stress protein synthesis and inhibition of synthesis of constitutive proteins. These changes in renal protein synthesis preceded overt renal injury, occurring in the early stages of nephropathy. Altered patterns of stress protein synthesis appeared to be target organ specific. The data suggest that altered protein synthesis patterns may serve as biomarkers of renal injury.

Diversity analysis of methanogens in rumen of Bubalus bubalis by 16S riboprinting and sequence analysis

The molecular diversity of rumen methanogens was investigated by 16S rDNA gene library prepared from the rumen contents obtained from Murrah buffaloes in India. Genomic DNA was isolated from adult male fistulated buffaloes and PCR conditions were set up using specific primers. Amplified product was cloned into a suitable vector, and the positive clones were selected assuming based on blue-white screening and sequenced. Positive clones were reamplified and the resulting PCR products were further subjected to Amplified Ribosomal DNA Restriction Analysis (ARDRA) by using HaeIII enzyme. A total of 108 clones were examined, and the analysis revealed 16 phylotypes. Out of sixteen phylotypes, nine phylotypes belong to the uncultured group of methanogens, and the rest of seven phylotypes belong to the order Methanomicrobiales, Methanococcales and Methanobacteriales. Out of the 108 rDNA clones, 66 clones which constitute 61.1% of the total clone representing 9 phylotypes, show less than 97% sequence similarity with any of the cultured strain of methanogens. The second largest group of clones (24 clones) represented by four phylotypes show a sequence similarity ranging from 91% to 99% with Methanomicrobium mobile strain of methanogens. The third group of 16S rDNA clones clustered along with M. burtonii strain of methanogens. This group consists of 6 clones and constitutes about 5.5% of the total clones and represented by only single phylotype. Fourth and fifth clusters of 16S rDNA clones consist of 5 and 7 clones respectively, and these were matched with Methanobrevibacter gottschalkii and Methanobrevibacter rumanatium strain of methanogens and constitute about 4.6% and 6.4% of the total clones.

Structure modeling and inhibitor prediction ofNADP oxidoreductase enzyme from Methanobrevibacter smithii

The F420-dependent NADP oxidoreductase enzyme from Methanobrevibacter smithii catalyzes the important electron transfer step during methanogenesis. Therefore, it may act as potential target for blocking the process of methane formation. Its protein sequence is available in GenBank (accession number: ABQ86254.1) however no report has been found about its 3D protein structure. In this work, we first time claim 3D model structure of F420-dependent NADP oxidoreductase enzyme from Methanobrevibacter smithii by comparative homology modeling method. Swiss model and ESyPred3d (via Modeller 6v2) software's were generated the 3D model by detecting 1JAX (A) as template along with sequence identities of 34.272% and 35.40%. Furthermore, PROCHECK with Ramachandran plot and ProSA analysis revealed that swiss model produced better model than Modeller6v2 with 98.90% of residues in favored and additional allowed regions (RM plot) as well as with ProSA Z score of -7.26. In addition, we investigated that the substrate F420 bound at the cavity of the model. Subsequently, inhibitor prediction study revealed that Lovastatin (-22.07 Kcal/mol) and Compactin (Mevastatin) (-21.91 Kcal/mol) produced more affinity for model structure of NADP oxidoreducatse as compared to F420 (-14.40 Kcal/mol). It indicates that the Lovastatin and Compactin (Mevastatin) compounds (Negative regulator) may act as potential inhibitor of F420 dependent NADP oxidoreducatse protein.

Functional amplification and preservation of human gut microbiota

Background: The availability of fresh stool samples is a prerequisite in most gut microbiota functional studies.

Objective: Strategies for amplification and long-term gut microbiota preservation from fecal samples would favor sample sharing, help comparisons and reproducibility over time and between laboratories, and improve the safety and ethical issues surrounding fecal microbiota transplantations.

Design: Taking advantage of in vitro gut-simulating systems, we amplified the microbial repertoire of a fresh fecal sample and assessed the viability and resuscitation of microbes after preservation with some common intracellular and extracellular acting cryoprotective agents (CPAs), alone and in different combinations. Preservation efficiencies were determined after 3 and 6 months and compared with the fresh initial microbiota diversity and metabolic activity, using the chemostat-based Environmental Control System for Intestinal Microbiota (ECSIM) in vitro model of the gut environment. Microbial populations were tested for fermentation gas, short-chain fatty acids, and composition of amplified and resuscitated microbiota, encompassing methanogenic archaea.

Results: Amplification of the microbial repertoire from a fresh fecal sample was achieved with high fidelity. Dimethylsulfoxide, alone or mixed with other CPAs, showed the best efficiency for functional preservation, and the duration of preservation had little effect.

Conclusions: The amplification and resuscitation of fecal microbiota can be performed using specialized in vitro gut models. Correct amplification of the initial microbes should ease the sharing of clinical samples and improve the safety of fecal microbiota transplantation.

Abbreviations: CDI, Clostridium difficile infection; CPA, cryoprotective agent; D, DMSO, dimethylsulfoxide; FMT, fecal microbiota transplantation; G, glycerol; IBD, inflammatory bowel disease; P, PEG-4000, polyethylene glycol 4000 g.mol⁻¹; SCFA, short-chain fatty acid; SNR, signal-to-noise ratio

Exposure to isocyanates predicts atopic dermatitis prevalence and disrupts therapeutic pathways in commensal bacteria

Atopic dermatitis (AD) is a chronic inflammatory skin condition increasing in industrial nations at a pace that suggests environmental drivers. We hypothesize that the dysbiosis associated with AD may signal microbial adaptations to modern pollutants. Having previously modeled the benefits of health-associated Roseomonas mucosa, we now show that R. mucosa fixes nitrogen in the production of protective glycerolipids and their ceramide by-products. Screening EPA databases against the clinical visit rates identified diisocyanates as the strongest predictor of AD. Diisocyanates disrupted the production of beneficial lipids and therapeutic modeling for isolates of R. mucosa as well as commensal Staphylococcus. Last, while topical R. mucosa failed to meet commercial end points in a placebo-controlled trial, the subgroup who completed the full protocol demonstrated sustained, clinically modest, but statistically significant clinical improvements that differed by study site diisocyanate levels. Therefore, diisocyanates show temporospatial and epidemiological association with AD while also inducing eczematous dysbiosis.

Is the methanogenic community reflecting the methane emissions of river sediments?-comparison of two study sites

Studies on methanogenesis from freshwater sediments have so far primarily focused on lake sediments. To expand our knowledge on the community composition of methanogenic archaea in river sediments, we studied the abundance and diversity of methanogenic archaea at two localities along a vertical profile (top 50 cm) obtained from sediment samples from Sitka stream (the Czech Republic). In this study, we compare two sites which previously have been shown to have a 10‐fold different methane emission. Archaeal and methanogen abundance were analyzed by real‐time PCR and T‐RFLP. Our results show that the absolute numbers for the methanogenic community (qPCR) are relatively stable along a vertical profile as well as for both study sites. This was also true for the archaeal community and for the three major methanogenic orders in our samples (Methanosarcinales, Methanomicrobiales, and Methanobacteriales). However, the underlying community structure (T‐RFLP) reveals different community compositions of the methanogens for both locations as well as for different depth layers and over different sampling times. In general, our data confirm that Methanosarcinales together with Methanomicrobiales are the two dominant methanogenic orders in river sediments, while members of Methanobacteriales contribute a smaller community and Methanocellales are only rarely present in this sediment. Our results show that the previously observed 10‐fold difference in methane emission of the two sites could not be explained by molecular methods alone.

Integrative multiomics analysis reveals host-microbe-metabolite interplays associated with the aging process in Singaporeans

The age-associated alterations in microbiomes vary across populations due to the influence of genetics and lifestyles. To the best of our knowledge, the microbial changes associated with aging have not yet been investigated in Singapore adults. We conducted shotgun metagenomic sequencing of fecal and saliva samples, as well as fecal metabolomics to characterize the gut and oral microbial communities of 62 healthy adult male Singaporeans, including 32 young subjects (age, 23.1 ± 1.4 years) and 30 elderly subjects (age, 69.0 ± 3.5 years). We identified 8 gut and 13 oral species that were differentially abundant in elderly compared to young subjects. By combining the gut and oral microbiomes, 25 age-associated oral-gut species connections were identified. Moreover, oral bacteria Acidaminococcus intestine and Flavonifractor plautii were less prevalent/abundant in elderly gut samples than in young gut samples, whereas Collinsella aerofaciens and Roseburia hominis showed the opposite trends. These results indicate the varied gut-oral communications with aging. Subsequently, we expanded the association studies on microbiome, metabolome and host phenotypic parameters. In particular, Eubacterium eligens increased in elderly compared to young subjects, and was positively correlated with triglycerides, which implies that the potential role of E. eligens in lipid metabolism is altered during the aging process. Our results demonstrated aging-associated changes in the gut and oral microbiomes, as well as the connections between metabolites and host-microbe interactions, thereby deepening the understanding of alterations in the human microbiome during the aging process in a Singapore population.

Computational finding of potential inhibitor for Cytochrome P450 Mono-oxygenases Enzyme of Mycobacterium tuberculosis

Cytochrome P450 mono-oxygenases (2UUQ) enzyme from Mycobacterium tuberculosis catalyzes oxidation of organic compounds such as lipids and steroidal hormones therefore remain as potential drug target. Currently available first line anti-tuberculosis drugs have been caused several side effects in the body as well as resistance development by mycobacterium against these drugs, necessitates the considerable need for finding new drugs. Therefore, we propose a structure based computational method to find a new potential inhibitor for cytochrome P450 mono-oxygenases enzyme. Compounds from several ligand databases were docked against the functional sites of 2UUQ (A) through the standard GEMDOCK v2.0 and AUTODOCK4.0 molecular docking tools. Commercially available chemical compound ZINC00004165 (5-[3-(2-nitroimidazol-1-yl) propyl] phenanthridine) has produced top rank with lowest interaction energy of -113.2 (via GEMDOCK) and lowest docking energy of -9.80 kcal/mol (via AUTODOCK) as compared to first line anti TB compounds. Z score and normal distribution analysis verified that the ZINC00004165 compound has more affinity towards 2UUQ in comparison to large number of random population of compounds. ZINC00004165 is also in agreement with the drug likeness properties of Lipinski rule of five without any violation. Therefore, our finding concludes that the commercial compound ZINC00004165 can act as a potential inhibitor against cytochrome P450 mono-oxygenases enzyme of Mycobacterium tuberculosis.

Shotgun metagenomic sequencing on skin microbiome indicates dysbiosis exists prior to the onset of atopic dermatitis

BACKGROUND

While the microbiome is increasingly seen as a targetable contributor to atopic dermatitis (AD), questions remain as to whether the dysbiosis is secondary to diseased skin or if it predates symptom onset. Previous work has evaluated how the skin microbiome changes with age and established the influence of factors like delivery mode and breastfeeding on global microbiome diversity. However, these studies were unable to identify taxa which predict subsequent AD.

METHODS

Skin swab samples were collected from the first week of life for 72 children in the neonatal intensive care unit (NICU) at a single site hospital. Participants were followed for 3 years to determine their health status. We applied shotgun metagenomic sequencing to assess the microbiome differences between 31 children who went on to develop AD and 41 controls.

RESULTS

We identified that subsequent development of AD was associated with differential abundance of several bacterial and fungal taxa as well as several metabolic pathways, each of which have been previously associated with active AD.

CONCLUSIONS

Our work provides evidence of reproducibility for the previously reported dysbiotic signatures predating AD onset while also expanding prior findings through the first use of metagenomic assessment prior to AD onset. While extrapolation of our findings beyond the pre-term, NICU cohort is limited, our findings add to the evidence that the dysbiosis associated with AD pre-dates disease onset rather than reflect a secondary consequence of skin inflammation.

Molecular identification of the occurrence of magnetotactic bacteria in fresh water sediments (Czech Republic)

Magnetotactic bacteria (MTB) are of considerable interest because of their importance in the manufacture of various bioinspired materials. In order to find out the status of magnetotactic bacteria at three different sediment in Czech Republic, samples collected from both standing and running freshwaters were subjected to molecular diversity analysis by using 16S rRNA gene approach. Total community DNA from sediment sample was isolated and used for PCR, cloning and sequence analysis. Of the 24 analyzed sequences, six clones are closely related to Magnetobacterium sp. affiliated with the Nitrospira phylum which showed the dominance of Magnetobacterium phylotypes in the sample. This study will provide useful insight about the community structure of MTB in this particular geographical region. However more detailed and specific studies are warranted in order to properly assess the community structure of MTB’s in fresh water sediments.

Diisocyanates influence models of atopic dermatitis through direct activation of TRPA1

We recently used EPA databases to identify that isocyanates, most notably toluene diisocyanate (TDI), were the pollutant class with the strongest spatiotemporal and epidemiologic association with atopic dermatitis (AD). Our findings demonstrated that isocyanates like TDI disrupted lipid homeostasis and modeled benefit in commensal bacteria like Roseomonas mucosa through disrupting nitrogen fixation. However, TDI has also been established to activate transient receptor potential ankyrin 1 (TRPA1) in mice and thus could directly contribute to AD through induction of itch, rash, and psychological stress. Using cell culture and mouse models, we now demonstrate that TDI induced skin inflammation in mice as well as calcium influx in human neurons; each of these findings were dependent on TRPA1. Furthermore, TRPA1 blockade synergized with R. mucosa treatment in mice to improve TDI-independent models of AD. Finally, we show that the cellular effects of TRPA1 are related to shifting the balance of the tyrosine metabolites epinephrine and dopamine. This work provides added insight into the potential role, and therapeutic potential, or TRPA1 in the pathogenesis of AD.

Methanomethylophilus alvi gen. nov., sp. nov., a Novel Hydrogenotrophic Methyl-Reducing Methanogenic Archaea of the Order Methanomassiliicoccales Isolated from the Human Gut and Proposal of the Novel Family Methanomethylophilaceae fam. nov

The methanogenic strain Mx-05T was isolated from the human fecal microbiome. A phylogenetic analysis based on the 16S rRNA gene and protein marker genes indicated that the strain is affiliated with the order Methanomassiliicoccales. It shares 86.9% 16S rRNA gene sequence identity with Methanomassiliicoccus luminyensis, the only member of this order previously isolated. The cells of Mx-05T were non-motile cocci, with a diameter range of 0.4-0.7 μm. They grew anaerobically and reduced methanol, monomethylamine, dimethylamine, and trimethylamine into methane, using H2 as an electron donor. H2/CO2, formate, ethanol, and acetate were not used as energy sources. The growth of Mx-05T required an unknown medium factor(s) provided by Eggerthella lenta and present in rumen fluid. Mx-05T grew between 30 °C and 40 °C (optimum 37 °C), over a pH range of 6.9-8.3 (optimum pH 7.5), and between 0.02 and 0.34 mol.L-1 NaCl (optimum 0.12 mol.L-1 NaCl). The genome is 1.67 Mbp with a G+C content of 55.5 mol%. Genome sequence annotation confirmed the absence of the methyl branch of the H4MPT Wood-Ljungdahl pathway, as described for other Methanomassiliicoccales members. Based on an average nucleotide identity analysis, we propose strain Mx-05T as being a novel representative of the order Methanomassiliicoccales, within the novel family Methanomethylophilaceae, for which the name Methanomethylophilus alvi gen. nov, sp. nov. is proposed. The type strain is Mx-05T (JCM 31474T).

Prevalence of antibiotic-resistant Gram-negative bacteria having extended-spectrum β-lactamase phenotypes in polluted irrigation-purpose wastewaters from Indian agro-ecosystems

Antibiotic resistance in bacteria has emerged as a serious public health threat worldwide. Aquatic environments including irrigation-purpose wastewaters facilitate the emergence and transmission of antibiotic-resistant bacteria and antibiotic resistance genes leading to detrimental effects on human health and environment sustainability. Considering the paramount threat of ever-increasing antibiotic resistance to human health, there is an urgent need for continuous environmental monitoring of antibiotic-resistant bacteria and antibiotic resistance genes in wastewater being used for irrigation in Indian agro-ecosystems. In this study, the prevalence of antibiotic resistance in Gram-negative bacteria isolated from irrigation-purpose wastewater samples from Sirmaur and Solan districts of Himachal Pradesh was determined. Bacterial isolates of genera Escherichia, Enterobacter, Hafnia, Shigella, Citrobacter, and Klebsiella obtained from 11 different geographical locations were found to exhibit resistance against ampicillin, amoxyclav, cefotaxime, co-trimoxazole, tobramycin, cefpodoxime and ceftazidime. However, all the isolates were sensitive to aminoglycoside antibiotic gentamicin. Enterobacter spp. and Escherichia coli showed predominance among all the isolates. Multidrug-resistance phenotype was observed with isolate AUK-06 (Enterobacter sp.) which exhibited resistant to five antibiotics. Isolate AUK-02 and AUK-09, both E. coli strains showed resistant phenotypes to four antibiotics each. Phenotypic detection revealed that six isolates were positive for extended-spectrum β-lactamases which includes two isolates from Enterobacter spp. and E. coli each and one each from Shigella sp. and Citrobacter sp. Overall, the findings revealed the occurrence of antibiotic resistant and ESBL-positive bacterial isolates in wastewaters utilized for irrigation purpose in the study area and necessitate continuous monitoring and precautionary interventions. The outcomes of the study would be of significant clinical, epidemiological, and agro-environmental importance in designing effective wastewater management and environmental pollution control strategies.

TRPA1 Influences Staphylococcus aureus Skin Infection in Mice and Associates with HIF-1a and MAPK Pathway Modulation

Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a major public health burden. Emerging antibiotic resistance has heightened the need for new treatment approaches for MRSA infection such as developing novel antimicrobial agents and enhancing the host's defense response. The thermo-ion channels Transient Receptor Potential (TRP-) A1 and V1 have been identified as modulators of S. aureus quorum sensing in cell culture models. However, their effects on in vivo infection control are unknown. In this study, we investigated the therapeutic effect of natural TRP ion channel inhibitors on MRSA skin infection in mice. While deletion of TRPV1 did not affect lesion size or inflammatory markers, TRPA1-/- mice demonstrated significantly reduced infection severity and abscess size. Treatment with natural inhibitors of TRPA1 with or without blockade of TRPV1 also reduced abscess size. Tissue transcriptomic data coupled with immunohistochemistry revealed that TRPA1 inhibition impacted heat shock protein expression (HSP), modulated the HIF-1a and MAPK pathways, and reduced IL4 expression. Additionally, metabolomics data showed an impact on purine and glycosaminoglycan pathways. Multi-omic integration of transcriptomic and metabolic data revealed that diacylglycerol metabolism was the likely bridge between metabolic and immunological impacts. Our findings suggest that TRPA1 antagonism could provide a promising and cost-effective therapeutic approach for reducing the severity of MRSA infection, and presents a novel underlying molecular mechanism.

Topical Steroid Withdrawal is a Targetable Excess of Mitochondrial NAD

Background

Topical corticosteroids (TCS) are first-line therapies for numerous skin conditions. Topical Steroid Withdrawal (TSW) is a controversial diagnosis advocated by patients with prolonged TCS exposure who report severe systemic reactions upon treatment cessation. However, to date there have been no systematic clinical or mechanistic studies to distinguish TSW from other eczematous disorders.

Methods

A re-analysis of a previous survey with eczematous skin disease was performed to evaluate potential TSW distinguishing symptoms. We subsequently conducted a pilot study of 16 patients fitting the proposed diagnostic criteria. We then performed: tissue metabolomics, transcriptomics, and immunostaining on skin biopsies; serum metabolomics and cytokine assessments; shotgun metagenomics on microbiome skin swabs; genome sequencing; followed by functional, mechanistic studies using human skin cell lines and mice.

Results

Clinically distinct TSW symptoms included burning, flushing, and thermodysregulation. Metabolomics and transcriptomics both implicated elevated NAD+ oxidation stemming from increased expression of mitochondrial complex I and conversion of tryptophan into kynurenine metabolites. These abnormalities were induced by glucocorticoid exposure both in vitro and in a cohort of healthy controls (N=19) exposed to TCS. Targeting complex I via either metformin or the herbal compound berberine improved outcomes in both cell culture and in an open-label case series for patients with TSW.

Conclusion

Taken together, our results suggest that TSW has a distinct dermatopathology. While future studies are needed to validate these results in larger cohorts, this work provides the first mechanistic evaluation into TSW pathology, and offers insights into clinical identification, pharmacogenomic candidates, and directed therapeutic strategies.

Antimony Compounds Associate with Atopic Dermatitis and Influence Models of Itch and Dysbiosis

Compared to the myriad of known triggers for rhinitis and asthma, environmental exposure research for atopic dermatitis (AD) is not well established. We recently reported that an untargeted search of U.S. Environmental Protection Agency (EPA) databases versus AD rates by United States (U.S.) postal codes revealed that isocyanates, such as toluene diisocyanate (TDI), are the pollutant class with the strongest spatiotemporal and epidemiologic association with AD. We further demonstrated that (di)isocyanates disrupt ceramide-family lipid production in commensal bacteria and activate the thermo-itch host receptor TRPA1. In this report, we reanalyzed regions of the U.S. with low levels of diisocyanate pollution to assess if a different chemical class may contribute. We identified antimony compounds as the top associated pollutant in such regions. Exposure to antimony compounds would be expected from brake dust in high-traffic areas, smelting plants, bottled water, and dust from aerosolized soil. Like TDI, antimony inhibited ceramide-family lipid production in Roseomonas mucosa and activated TRPA1 in human neurons. While further epidemiologic research will be needed to directly evaluate antimony exposure with surrounding AD prevalence and severity, these data suggest that compounds which are epidemiologically associated with AD, inhibit commensal lipid production, and activate TRPA1 may be causally related to AD pathogenesis.

De novo assembly of Roseomonas mucosa isolates from healthy human volunteers used to treat atopic dermatitis

Roseomonas mucosa is a bacterium that is found in the natural microbiota of human skin. Here, we present de novo sequence assemblies from R. mucosa isolated from the skin microflora of three healthy human volunteers that were used to treat atopic dermatitis patients.

Spatial modeling connecting childhood atopic dermatitis prevalence with household exposure to pollutants

BACKGROUND

Atopic dermatitis (AD) is a chronic, inflammatory disease characterized by dry, pruritic skin. In the U.S., the prevalence of AD has increased over three-fold since the 1970s. We previously reported a geographic association between isocyanate-containing air pollution and AD as well as mechanistic data demonstrating that isocyanates induce skin dysbiosis and activate the host itch receptor TRPA1. However, non-spatial models are susceptible to spatial confounding and may overlook other meaningful associations.

METHODS

We added spatial analysis to our prior model, contrasting pollution data with clinical visits. In addition, we conducted a retrospective case-control survey of childhood exposure to BTEX-related products. Finally, we assessed implicated compounds, in pure form and as part of synthetic fabric, for their effect on the growth and metabolism of skin commensal bacteria.

RESULTS

Spatial analysis implicate benzene, toluene, ethylbenzene, and, most significantly, xylene (BTEX) compounds. Survey odds ratios for AD were significant for xylene-derived polyester bed sheets (OR = 9.5; CI 2.2-40.1) and diisocyanate-containing wallpaper adhesive (OR = 6.5; CI 1.5-27.8). Staphylococcus aureus lives longer on synthetic textiles compared to natural textiles. Meanwhile, synthetic fabric exposure shifts the lipid metabolism of health-associated commensals (Roseomonas mucosa and S. epidermidis) away from therapeutic pathways.

CONCLUSIONS

We propose that BTEX chemicals in their raw forms and in synthetic products represent a unifying hypothesis for environmentally induced AD flares through their ability to create dysbiosis in the skin microbiota and directly activate TRPA1. Unequal distribution of these pollutants may also influence racial disparities in AD rates.

The circadian metabolome of atopic dermatitis

BACKGROUND

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by dry, pruritic skin. Several studies have described nocturnal increases in itching behavior, suggesting a role for the circadian rhythm in modulating symptom severity. However, the circadian rhythm of metabolites in the skin and serum of patients with AD is yet to be described.

OBJECTIVE

We sought to assess circadian patterns of skin and serum metabolism in patients with AD.

METHODS

Twelve patients with moderate to severe AD and 5 healthy volunteers were monitored for 28 hours in a controlled environment. Serum was collected every 2 hours and tape strips every 4 hours from both lesional and nonlesional skin in participants with AD and location-, sex-, and age-matched healthy skin of controls. We then performed an untargeted metabolomics analysis, examining the circadian peaks of metabolism in patients with AD.

RESULTS

Distinct metabolic profiles were observed in AD versus control samples. When accounting for time of collection, the greatest differences in serum metabolic pathways were observed in arachidonic acid, steroid biosynthesis, and terpenoid backbone biosynthesis. We identified 42 circadian peaks in AD or control serum and 17 in the skin. Pathway enrichment and serum-skin metabolite correlation varied throughout the day. Differences were most evident in the late morning and immediately after sleep onset.

CONCLUSIONS

Although limited by a small sample size and observational design, our findings suggest that accounting for sample collection time could improve biomarker detection studies in AD and highlight that metabolic changes may be associated with nocturnal differences in symptom severity.