Formylpeptide receptor 1 contributes to epidermal barrier dysfunction-induced skin inflammation through NOD-like receptor C4-dependent keratinocyte activation.

BACKGROUND: Skin barrier dysfunction may both initiate and aggravate skin inflammation. However, the mechanisms involved in the inflammation process remain largely unknown. OBJECTIVES: We sought to determine how skin barrier dysfunction enhances skin inflammation and molecular mechanisms. METHODS: Skin barrier defect mice were established by tape stripping or topical use of acetone on wildtype mice, or filaggrin deficiency. RNA-Seq was employed to analyse the differentially expressed genes in mice with skin barrier defects. Primary human keratinocytes were transfected with formylpeptide receptor (FPR)1 or protein kinase R-like endoplasmic reticulum (ER) kinase (PERK) small interfering RNA to examine the effects of these gene targets. The expressions of inflammasome NOD-like receptor (NLR)C4, epidermal barrier genes and inflammatory mediators were evaluated. RESULTS: Mechanical (tape stripping), chemical (acetone) or genetic (filaggrin deficiency) barrier disruption in mice amplified the expression of proinflammatory genes, with transcriptomic profiling revealing overexpression of formylpeptide receptor (Fpr1) in the epidermis. Treatment with the FPR1 agonist fMLP in keratinocytes upregulated the expression of the NLRC4 inflammasome and increased interleukin-1ß secretion through modulation of ER stress via the PERK-eIF2α-C/EBP homologous protein pathway. The activation of the FPR1-NLRC4 axis was also observed in skin specimens from old healthy individuals with skin barrier defect or elderly mice. Conversely, topical administration with a FPR1 antagonist, or Nlrc4 silencing, led to the normalization of barrier dysfunction and alleviation of inflammatory skin responses in vivo. CONCLUSIONS: In summary, our findings show that the FPR1-NLRC4 inflammasome axis is activated upon skin barrier disruption and may explain exaggerated inflammatory responses that are observed in disease states characterized by epidermal dysfunction. Pharmacological inhibition of FPR1 or NLRC4 represents a potential therapeutic target.

Effects of media length on biofilms and nitrification in moving bed biofilm reactors.

Biofilms grown on free-floating plastic media are increasingly being used to cultivate biofilms in integrated fixed film activated sludge (IFAS) and moving bed bioreactor (MBBR) systems for wastewater treatment with the common goal of increasing nitrogen removal. Fundamental principles of fluid dynamics dictate that the length of internal media channels affects fluid velocities and shear forces across biofilm surfaces, which in turn should affect rates of mass transfer and biofilm growth and activity, but little is known about media length effects on water quality and biofilm characteristics. It was hypothesized that length affects biofilm thickness, microbial populations and their activities, and system performance. Nitrification rates and biofilm characteristics were monitored in parallel continuous flow, bench-scale MBBRs systems with media length as a controlled variable. Longer media produced biofilms with approximately twice the thickness and twice the mass per unit area than did media with one-third their length. Based on calculated head losses, the combined effects of length and constriction of internal channels led to an estimated 77% reduction in fluid velocity through the longer media relative to the shorter media. Longer media demonstrated more rapid development of nitrite oxidizing bacteria (NOB) activity than the shorter media over much of the study, as indicated by measurements of nitrite and nitrate, but AOB activity was similar in the two media. Both biomass and NOB activity were concentrated toward media ends, while ammonia oxidizing bacteria (AOB) activity was uniformly distributed across the media, based on testing of sectioned media. 16s rRNA amplicon sequencing indicated the presence of several putative heterotrophic nitrifying families, particularly Xanthomonadaceae, Comamonadadeae and Microbacteriaceae, as well as the autotrophic Bradyrhizobiacea (which includes the NOB Nitrobacter) were common on both media throughout the study. The short media enriched for Nitrosomonadaceae, which includes the AOB genus Nitrosomonas, while minimal autotrophic AOBs were found in the long media biofilm. These results provide insights to the design of media for improved performance, particularly with respect to nitrite versus nitrate production, which may be useful to improve nitrification and for energy saving processes for nitrogen removal such as deammonification. The research also provides fundamental insights regarding the effects of media geometry on biofilm structure and function, which advances our understanding of environmental factors affecting biofilm development.

Effects of Methyl, Ester, and Amine Surface Groups on Microbial Activity and Communities in Nitrifying Biofilms.

The objective of this study was to determine how different attachment surface chemistries affected the initial and long-term performance and microbial populations of nitrifying biofilms under well-controlled hydrodynamic mixing conditions. While much previous research has focused on the effects of surface properties such as hydrophobicity on bacterial attachment in pure cultures, this study evaluated the effects of specific functional groups on mixed culture composition and functional behavior. Three surfaces with varying hydrophobicity and charge were evaluated for biofilm community development and performance: unmodified poly(dimethylsiloxane) (PDMS), which included terminal methyl groups and was relatively hydrophobic (P-Methyl), PDMS silanized with ester groups (P-Ester), which was uncharged and relatively hydrophilic, and PDMS modified with amine groups (P-Amine), which possessed a positive charge and was the most hydrophilic. The surface chemistries of the three attachment surfaces were characterized by contact angle goniometry, Fourier transform infrared (FTIR) spectroscopy, and X-ray photoelectron spectroscopy (XPS). These surfaces were inoculated with dilute activated sludge, and biofilms were grown in rotating annular bioreactors for 80 days, with experimental triplicates. Nitrification rates increased most rapidly in P-Amine biofilm reactors, and their biofilm communities contained significantly more Nitrosomonas (p < 0.05) than those on the other surfaces in early growth stages (days 40-50). From days 50-60, the P-Amine surface biofilm had significantly higher nitrate production rates than the P-Methyl and P-Ester biofilms. The biofilms grown on the P-Amine and P-Methyl surfaces were significantly (p < 0.05) more diverse than the P-Ester biofilms, containing higher relative abundances of the order Rhizobiales, including a significantly higher abundance of the nitrifying genus Nitrobacter (p < 0.05), which coincided with higher rates of nitrate generation. Conversely, biofilms grown on the uncharged hydrophilic P-Ester surface were consistently less productive and had lower diversity than biofilms on the other surfaces. These results indicate that surface chemistry may be a useful design parameter to improve the performance of nitrifying biofilm systems for wastewater treatment and that surface chemistry affects mixed biofilm community composition.

Symmetric drug-related intertriginous and flexural exanthema: Clinicopathologic study of 19 cases and review of literature.

BACKGROUND: Symmetric drug-related intertriginous and flexural exanthema (SDRIFE) is a cutaneous drug reaction characterized by gluteal/anogenital erythema and symmetric involvement of other intertriginous location(s) without systemic signs. Clinicopathologic characterization has been limited to case reports and small series. We describe 19 new cases and review the literature to better define the clinical and histopathologic spectrum of SDRIFE. METHODS: Pathology archives were searched for "SDRIFE" and "baboon syndrome." Cases meeting clinical criteria were included. Clinical and histopathologic features were recorded. Previous reports of SDRIFE with histopathologic descriptions were reviewed. RESULTS: Nineteen new cases were included, over half triggered by antibiotics. Six new causative medications were identified. Median onset was 7 days. Typical lesions were erythematous plaques or papules with or without scale. The most common histopathologic finding was superficial perivascular lymphocytic infiltrate followed by dermal eosinophils, spongiosis, and orthokeratosis. Basal vacuolization and apoptotic keratinocytes were less common. Interstitial histiocytes were present in almost half of our cases. Other findings included atypical lymphocytes and "flame figure." CONCLUSIONS: Appreciation of the range of inciting medications and clinicopathologic features in SDRIFE will improve recognition of this condition. Although many histopathologic features overlap with other common dermatitides, biopsy may assist in excluding key clinical mimics.

Effects of surface skewness on local shear stresses, biofilm activity, and microbial communities for wastewater treatment.

This study's objective was to assess attachment surface skewness (asymmetric surface height variation) effects on biofilm development. 3D printed molds were used to create surfaces with 300 µm features to provide opposite skewness but identical roughness values. Surfaces with negative skewness had consistently greater nitrite oxidation and biomass growth than other surfaces during biofilm development when studied in annular bioreactor systems. CFD modelling predicted local shear stress differences that could explain experimental results. 16 s rRNA gene amplicon sequencing revealed population differences, including relatively high Acinetobacter and Terrimonas fractions on the negative skew surfaces, and PCoA analyses indicated the flat surface populations diverged from the skew surfaces by the study's end. The results suggest skewness is particularly important in systems where biofilms have not overgrown surface features, as in system startup, thin biofilms, and shorter time frame studies, which includes much previous microbial attachment research.

Folliculitis Induced by Laser Hair Removal: Proposed Mechanism and Treatment.

The neodymium:aluminum garnet laser has emerged as a generally well-tolerated tool for hair removal; however, some patients develop a folliculitis after treatment, which can limit utility. To our knowledge, the literature is currently lacking an adequate description of the etiology of laser-induced folliculitis or strategies to prevent and manage it. We present the case of a 33-year-old Caucasian male patient who developed a robust laser-induced folliculitis. We discuss management strategies and the possible mechanism of onset, as well as hypothesize that the mechanism driving laser-induced folliculitis is similar to that seen with pseudofolliculitis barbae, as the nidus for the inflammatory response appeared to be the hairs undergoing extrusion through the skin. While laser-induced folliculitis is a self-limited complication, it might discourage patients from seeking laser hair removal. In patients known to develop this adverse effect or those with hair features potentially more prone to developing folliculitis (i.e. curly, coarse hair or pili multigemini), it might be reasonable to treat with prophylactic doxycycline and topical steroids along with gentle washing techniques to assist in depilation. As demonstrated in our case, this might help to decrease the severity and duration of laser-induced folliculitis.

A Case of Adjacent, Clonally Distinct Borderline Melanocytic Tumors on the Arm.

Atypical Spitz tumor (AST) is a melanocytic proliferation that shares histopathologic features of Spitz nevus and spitzoid melanoma. Distinction of AST from spitzoid melanoma is critical because the majority of ASTs will follow an indolent course. Array-based comparative genomic hybridization (aCGH) has been suggested as a potential tool for evaluating malignant potential in spitzoid tumors. We present a case of a 52-year-old woman with an AST in which aCGH was crucial in guiding correct diagnosis and management. The patient first presented with a flesh-colored papule on her arm that was changing color. Biopsy revealed a dermal nevoid melanocytic tumor of indeterminate histopathology, favored to be a severely atypical nevus. The tumor was excised. One year later, another flesh-colored papule proximal to the excision site of the first tumor was biopsied and showed a predominantly dermal atypical spitzoid melanocytic proliferation with a differential diagnosis of AST versus spitzoid melanoma. Recurrent or metastatic melanoma was also a concern given proximity to the previous excision site. Molecular analysis of both lesions by aCGH revealed distinct molecular signatures, supporting the 2 tumors to be clonally unrelated. Furthermore, the new tumor displayed limited evidence of genomic instability, supporting classification as an AST with predicted indolent behavior. This case highlights the utility of aCGH in evaluating borderline melanocytic lesions, including assessment of malignant potential in ASTs, and clonality analysis to assist in exclusion of metastatic disease.

IFN-γ enhances cell-mediated cytotoxicity against keratinocytes via JAK2/STAT1 in lichen planus.

Lichen planus (LP) is a chronic debilitating inflammatory disease of unknown etiology affecting the skin, nails, and mucosa with no current FDA-approved treatments. It is histologically characterized by dense infiltration of T cells and epidermal keratinocyte apoptosis. Using global transcriptomic profiling of patient skin samples, we demonstrate that LP is characterized by a type II interferon (IFN) inflammatory response. The type II IFN, IFN-γ, is demonstrated to prime keratinocytes and increase their susceptibility to CD8+ T cell-mediated cytotoxic responses through MHC class I induction in a coculture model. We show that this process is dependent on Janus kinase 2 (JAK2) and signal transducer and activator of transcription 1 (STAT1), but not JAK1 or STAT2 signaling. Last, using drug prediction algorithms, we identify JAK inhibitors as promising therapeutic agents in LP and demonstrate that the JAK1/2 inhibitor baricitinib fully protects keratinocytes against cell-mediated cytotoxic responses in vitro. In summary, this work elucidates the role and mechanisms of IFN-γ in LP pathogenesis and provides evidence for the therapeutic use of JAK inhibitors to limit cell-mediated cytotoxicity in patients with LP.

Battling Neuropathic Scar Pain With Botulinum Toxin

Botulinum toxin type A (BTA) is a neurotoxic protein that prevents the release of neurotransmitters from presynaptic nerves and has shown promise in treating neuropathic pain. Recently, BTA has been used to treat painful keloids and scars. We present a patient with refractory neuropathic pain in a normotrophic spread-scar treated with the injection of BTA. A 47-year-old Caucasian female with a history of invasive melanoma of the left upper arm presented with pain in her excision scar, which she described as a "pins and needles" sensation alternating with a dull, deep ache. She had previously tried topical lidocaine, topical and intralesional steroids, and oral gabapentin without improvement. We treated the patient with 50 U of onabotulinumtoxinA intradermally at 1-1.5 cm intervals within and immediately around the perimeter of the scar. At 1-week follow-up, she reported a 10% decrease in her pain. Four weeks after the procedure, she reported a 50% decrease in pain with smoothening of the scar surface, which has been durable for over 5 months. Scar pain can significantly impair quality of life and treatment protocols have not been established for normotrophic scars. Many trials have focused on improving appearance and reducing symptoms in hypertrophic and keloid scars, but few have evaluated therapies for normotrophic scars. BTA has been studied as a treatment for painful hypertrophic and keloid scars with promising results. Our patient had a marked reduction in pain and improvement in scar texture at 1-month follow-up, which has been maintained thus far, indicating that intradermal BTA may be a simple and useful tool in treating painful normotrophic scars. J Drugs Dermatol. 2019;18(9):937-938.

Performance and diversity responses of nitrifying biofilms developed on varied materials and topographies to stepwise increases of aeration.

Nitrifying biofilms were grown on 3D-printed nylon with three different surface characteristics (flat, millimeter-scale indentations, and indentations with activated carbon (AC) coating) and were subjected to sequentially increasing aeration-based shear to determine the interplay between surface, performance, and microbial populations towards improved design of wastewater treatment media. Biofilms were evaluated for nitrification, biomass detachment, and microbial composition based on Illumina 16s rRNA sequencing. Indentations provided greater stability over flat with respect to population diversity after detachment events but did not improve ammonia removal. AC-surface biofilm had significantly higher removal than uncoated surfaces at low aeration (1.0 L/min, fine) and significantly lower at high aeration (5.0 L/min, coarse). Principal component analyses of microbial communities illustrated temporal shifts over two similar cycles of growth and shear-induced biomass loss, demonstrating that biofilms grew similar consortia across all surfaces, but tended to revert to earlier individual compositions after shear events.

Psammomatous Squamous Cell Carcinoma of the Skin.

Psammoma bodies (PBs) are concentric, lamellated calcifications commonly observed in malignancies such as papillary thyroid carcinoma and serous carcinoma of the ovary in which they may serve prognostic value. PBs are rare in cutaneous squamous cell carcinoma (cSCC), with only 1 previously reported case. Here, we present 3 cases of cSCC displaying PBs. One case occurred in the setting of end-stage renal disease, whereas the other 2 cases were in patients who did not have comorbid conditions that might predispose to hypercalcemia and dystrophic calcification. All 3 tumors demonstrated classic immunophenotypic findings of cSCC. Our findings indicate that PBs are a rare but recurrent phenomenon in cSCC, with unknown prognostic significance. The potential for PB formation in cSCC should be kept in mind, as this may represent a diagnostic pitfall in tumors with limited sampling or unusual morphologies.

Magnetic orientation in C. elegans relies on the integrity of the villi of the AFD magnetosensory neurons.

The magnetic field of the earth provides many organisms with sufficient information to successfully navigate through their environments. While evidence suggests the widespread use of this sensory modality across many taxa, it remains an understudied sensory modality. We have recently showed that the nematode C. elegans orients to earth-strength magnetic fields using the first pair of described magnetosensory neurons, AFDs. The AFD cells are a pair of ciliated sensory neurons crowned by fifty villi known to be implicated in temperature sensation. We investigated the potential importance of these subcellular structures for the performance of magnetic orientation. We show that ciliary integrity and villi number are essential for magnetic orientation. Mutants with impairments AFD cilia or villi structure failed to orient to magnetic fields. Similarly, C. elegans larvae possessing immature AFD neurons with fewer villi were also unable to orient to magnetic fields. Larvae of every stage however retained the ability to orient to thermal gradients. To our knowledge, this is the first behavioral separation of magnetic and thermal orientation in C. elegans. We conclude that magnetic orientation relies on the function of both cilia and villi in the AFD neurons. The role of villi in multiple sensory transduction pathways involved in the sensory transduction of vectorial stimuli further supports the likely role of the villi of the AFD neurons as the site for magnetic field transduction. The genetic and behavioral tractability of C. elegans make it a promising system for uncovering potentially conserved molecular mechanisms by which animals across taxa detect and orient to magnetic fields.

Methods for increasing the rate of anammox attachment in a sidestream deammonification MBBR.

Deammonification (partial nitritation-anammox) is a proven process for the treatment of high-nitrogen waste streams, but long startup time is a known drawback of this technology. In a deammonification moving bed biofilm reactor (MBBR), startup time could potentially be decreased by increasing the attachment rate of anammox bacteria (AMX) on virgin plastic media. Previous studies have shown that bacterial adhesion rates can be increased by surface modification or by the development of a preliminary biofilm. This is the first study on increasing AMX attachment rates in a deammonification MBBR using these methods. Experimental media consisted of three different wet-chemical surface treatments, and also media transferred from a full-scale mainstream fully nitrifying integrated fixed-film activated sludge (IFAS) reactor. Following startup of a full-scale deammonification reactor, the experimental media were placed in the full-scale reactor and removed for activity rate measurements and biomass testing after 1 and 2 months. The media transferred from the IFAS process exhibited a rapid increase in AMX activity rates (1.1 g/m(2)/day NH(4)(+) removal and 1.4 g/m(2)/day NO(2)(-) removal) as compared to the control (0.2 g/m(2)/day NH(4)(+) removal and 0.1 g/m(2)/day NO(2)(-) removal) after 1 month. Two out of three of the surface modifications resulted in significantly higher AMX activity than the control at 1 and 2 months. No nitrite oxidizing bacteria activity was detected in either the surface modified media or IFAS media batch tests. The results indicate that startup time of a deammonification MBBR could potentially be decreased through surface modification of the plastic media or through the transfer of media from a mature IFAS process.

Conjugated gold nanoparticles as a tool for probing the bacterial cell envelope: The case of Shewanella oneidensis MR-1.

The bacterial cell envelope forms the interface between the interior of the cell and the outer world and is, thus, the means of communication with the environment. In particular, the outer cell surface mediates the adhesion of bacteria to the surface, the first step in biofilm formation. While a number of ligand-based interactions are known for the attachment process in commensal organisms and, as a result, opportunistic pathogens, the process of nonspecific attachment is thought to be mediated by colloidal, physiochemical, interactions. It is becoming clear, however, that colloidal models ignore the heterogeneity of the bacterial surface, and that the so-called nonspecific attachment may be mediated by specific regions of the cell surface, whether or not the relevant interaction is ligand-mediate. The authors introduce surface functionalized gold nanoparticles to probe the surface chemistry of Shewanella oneidensis MR-1 as it relates to surface attachment to ω-substituted alkanethiolates self-assembled monolayers (SAMs). A linear relationship between the attachment of S. oneidensis to SAM modified planar substrates and the number of similarly modified nanoparticles attached to the bacterial surfaces was demonstrated. In addition, the authors demonstrate that carboxylic acid-terminated nanoparticles attach preferentially to the subpolar region of the S. oneidensis and obliteration of that binding preference corresponds in loss of attachment to carboxylic acid terminated SAMs. Moreover, this region corresponds to suspected functional regions of the S. oneidensis surface. Because this method can be employed over large numbers of cells, this method is expected to be generally applicable for understanding cell surface organization across populations.

Bilirubin oxidase based enzymatic air-breathing cathode: Operation under pristine and contaminated conditions.

The performance of bilirubin oxidase (BOx) based air breathing cathode was constantly monitored over 45 days. The effect of electrolyte composition on the cathode oxygen reduction reaction (ORR) output was investigated. Particularly, deactivation of the electrocatalytic activity of the enzyme in phosphate buffer saline (PBS) solution and in activated sludge (AS) was evaluated. The greatest drop in current density was observed during the first 3 days of constant operation with a decrease of ~60 µA cm(-2) day(-1). The rate of decrease slowed to ~10 µA cm(-2) day(-1) (day 3 to 9) and then to ~1.5 µA cm(-2)day(-1) thereafter (day 9 to 45). Despite the constant decrease in output, the BOx cathode generated residual current after 45 days operations with an open circuit potential (OCP) of 475 mV vs. Ag/AgCl. Enzyme deactivation was also studied in AS to simulate an environment close to the real waste operation with pollutants, solid particles and bacteria. The presence of low-molecular weight soluble contaminants was identified as the main reason for an immediate enzymatic deactivation within few hours of cathode operation. The presence of solid particles and bacteria does not affect the natural degradation of the enzyme.

High catalytic activity and pollutants resistivity using Fe-AAPyr cathode catalyst for microbial fuel cell application.

For the first time, a new generation of innovative non-platinum group metal catalysts based on iron and aminoantipyrine as precursor (Fe-AAPyr) has been utilized in a membraneless single-chamber microbial fuel cell (SCMFC) running on wastewater. Fe-AAPyr was used as an oxygen reduction catalyst in a passive gas-diffusion cathode and implemented in SCMFC design. This catalyst demonstrated better performance than platinum (Pt) during screening in "clean" conditions (PBS), and no degradation in performance during the operation in wastewater. The maximum power density generated by the SCMFC with Fe-AAPyr was 167 ± 6 µW cm(-2) and remained stable over 16 days, while SCMFC with Pt decreased to 113 ± 4 µW cm(-2) by day 13, achieving similar values of an activated carbon based cathode. The presence of S(2-) and showed insignificant decrease of ORR activity for the Fe-AAPyr. The reported results clearly demonstrate that Fe-AAPyr can be utilized in MFCs under the harsh conditions of wastewater.

Influence of anode surface chemistry on microbial fuel cell operation.

Self-assembled monolayers (SAMs) modified gold anodes are used in single chamber microbial fuel cells for organic removal and electricity generation. Hydrophilic (N(CH3)3(+), OH, COOH) and hydrophobic (CH3) SAMs are examined for their effect on bacterial attachment, current and power output. The different substratum chemistry affects the community composition of the electrochemically active biofilm formed and thus the current and power output. Of the four SAM-modified anodes tested, N(CH3)3(+) results in the shortest start up time (15 days), highest current achieved (225 µA cm(-2)) and highest MFC power density (40 µW cm(-2)), followed by COOH (150 µA cm(-2) and 37 µW cm(-2)) and OH (83 µA cm(-2) and 27 µW cm(-2)) SAMs. Hydrophobic SAM decreases electrochemically active bacteria attachment and anode performance in comparison to hydrophilic SAMs (CH3 modified anodes 7 µA cm(-2) anodic current and 1.2 µW cm(-2) MFC's power density). A consortium of Clostridia and δ-Proteobacteria is found on all the anode surfaces, suggesting a synergistic cooperation under anodic conditions.