Th17 cytokines stimulate CCL20 expression in keratinocytes in vitro and in vivo: implications for psoriasis pathogenesis

T helper (Th) 17 cells have recently been implicated in psoriasis pathogenesis, but mechanisms of how these cells traffic into inflamed skin are unknown. By immunostaining for interleukin (IL)-17A and IL-22, we show numerous cells present in psoriasis lesions that produce these cytokines. We next found that Th17 cytokines (IL-17A, IL-22, and tumor necrosis factor (TNF)-alpha) markedly increased the expression of CC chemokine ligand (CCL) 20, a CC chemokine receptor (CCR)6 ligand, in human keratinocyte monolayer and raft cultures in a dose- and time-dependent manner. Lastly, we showed in mice that subcutaneous injection with recombinant IL-17A, IL-22, or TNF-alpha led to the upregulation of both CCL20 and CCR6 expression in skin as well as cutaneous T-cell infiltration. Taken together, these data show that Th17 cytokines stimulate CCL20 production in vitro and in vivo, and thus provide a potential explanation of how CCR6-positive Th17 cells maintain their continual presence in psoriasis through a positive chemotactic feedback loop.

Tight junction channel regulation by interclaudin interference

Tight junctions form selectively permeable seals across the paracellular space. Both barrier function and selective permeability have been attributed to members of the claudin protein family, which can be categorized as pore-forming or barrier-forming. Here, we show that claudin-4, a prototypic barrier-forming claudin, reduces paracellular permeability by a previously unrecognized mechanism. Claudin-4 knockout or overexpression has minimal effects on tight junction permeability in the absence of pore-forming claudins. However, claudin-4 selectively inhibits flux across cation channels formed by claudins 2 or 15. Claudin-4-induced loss of claudin channel function is accompanied by reduced anchoring and subsequent endocytosis of pore-forming claudins. Analyses in nonepithelial cells show that claudin-4, which is incapable of independent polymerization, disrupts polymeric strands and higher order meshworks formed by claudins 2, 7, 15, and 19. This process of interclaudin interference, in which one claudin disrupts higher order structures and channels formed by a different claudin, represents a previously unrecognized mechanism of barrier regulation.

Maternal diabetes and obesity influence the fetal epigenome in a largely Hispanic population

Background

Obesity and diabetes mellitus are directly implicated in many adverse health consequences in adults as well as in the offspring of obese and diabetic mothers. Hispanic Americans are particularly at risk for obesity, diabetes, and end-stage renal disease. Maternal obesity and/or diabetes through prenatal programming may alter the fetal epigenome increasing the risk of metabolic disease in their offspring. The aims of this study were to determine if maternal obesity or diabetes mellitus during pregnancy results in a change in infant methylation of CpG islands adjacent to targeted genes specific for obesity or diabetes disease pathways in a largely Hispanic population.

Methods

Methylation levels in the cord blood of 69 newborns were determined using the Illumina Infinium MethylationEPIC BeadChip. Over 850,000 different probe sites were analyzed to determine whether maternal obesity and/or diabetes mellitus directly attributed to differential methylation; epigenome-wide and regional analyses were performed for significant CpG sites.

Results

Following quality control, agranular leukocyte samples from 69 newborns (23 normal term (NT), 14 diabetes (DM), 23 obese (OB), 9 DM/OB) were analyzed for over 850,000 different probe sites. Contrasts between the NT, DM, OB, and DM/OB were considered. After correction for multiple testing, 15 CpGs showed differential methylation from the NT, associated with 10 differentially methylated genes between the diabetic and non-diabetic subgroups, CCDC110, KALRN, PAG1, GNRH1, SLC2A9, CSRP2BP, HIVEP1, RALGDS, DHX37, and SCNN1D. The effects of diabetes were partly mediated by the altered methylation of HOOK2, LCE3C, and TMEM63B. The effects of obesity were partly mediated by the differential methylation of LTF and DUSP22.

Conclusions

The presented data highlights the associated altered methylation patterns potentially mediated by maternal diabetes and/or obesity. Larger studies are warranted to investigate the role of both the identified differentially methylated loci and the effects on newborn body composition and future health risk factors for metabolic disease. Additional future consideration should be targeted to the role of Hispanic inheritance. Potential future targeting of transgenerational propagation and developmental programming may reduce population obesity and diabetes risk.

Electrophysiologic Analysis of Tight Junction Size and Charge Selectivity

Tight junctions form selectively permeable barriers that limit paracellular flux across epithelial-lined surfaces. Rather than being absolute barriers, tight junctions in many tissues allow ions, water, and other small molecules to cross on the basis of size and charge selectivity via the high-capacity pore pathway. Most probes currently used to assess tight junction permeability exceed the maximum size capacity of the pore pathway. As a result, available analytical tools have generally been limited to measurement of transepithelial electrical resistances. These provide no information regarding size selectivity and, therefore, cannot be used to distinguish between the pore pathway and the leak pathway, a low-capacity route that accommodates larger macromolecules. This article describes use of dilution potential and bi-ionic potential measurements for analysis of tight junction size and charge selectivity within monolayers of cultured epithelial cells. © 2021 Wiley Periodicals LLC. Basic Protocol 1: Culture of MDCK monolayers on semipermeable supports and induction of claudin-2 expression Basic Protocol 2: Configuring voltage/current clamp and other equipment Basic Protocol 3: Measuring dilution and bi-ionic potentials Basic Protocol 4: Calculating ion permeabilities and pore diameter Support Protocol: Preparation of agar bridges and electrophysiology rig setup.

Exploring nurse suicide by firearms: A mixed-method longitudinal (2003-2017) analysis of death investigations

BACKGROUND

Previously it was noted that firearm use by nurses in suicide was changing. The Center for Disease Control and Prevention suicide dataset contains investigation narratives that no researcher has analyzed and may provide context to inform suicide prevention.

OBJECTIVE

Explore firearm deaths in nurse suicide. Second, test topic modeling techniques to analyze investigation narratives.

METHODS/STATISTICAL ANALYSIS

Mixed-method retrospective analysis of 739 nurse versus 94,838 nonnurse suicides. Odds ratios (OR) were calculated to determine relative incidence. After tokenization and stop word removal, Latent Dirichlet Analysis and Latent Semantic Indexing topic modeling techniques were applied. Topics were evaluated for clinical significance and content analysis performed.

RESULTS

Aim 1: Female nurses used firearms significantly less often than other females between 2003 and 2013 (OR: 0.71; p < .001; 95% confidence interval [CI]: 4.23%-9.83%). A rise in nurse firearm use occurred between 2014 and 2017; with rates now similar to nonnurse females (OR: 0.98; p = .7574; 95% CI: -2.68 to 3.49). Clinically relevant topics identified by topic modeling: preventable deaths, chronic pain, and job loss before suicide.

CONCLUSIONS

From this research we know that work-related issues in nurse suicides by firearms center around chronic pain, substance use, and job loss. The codes tied to suicidal ideation, previous attempt and/or depression, represented preventable deaths because it is known that if a weapon is removed from the home in these situations a suicide can be aborted. The change in firearm use warrants nurse education regarding firearm safety and suicide prevention. Topic modeling holds promise in focusing analyses of suicide investigations.

Mechanochemical control systems regulating animal cell size

Cell size regulation arises from physical manifestations of cell proliferation and metabolic pathways. On one hand, coordination between these systems yields a constant cell size over generations to maintain cell size homeostasis. However, active regulation of cell size is crucial to physiology and to establish broad variation of cell sizes within an individual organism, and is accomplished via physical and biochemical pathways modulated by myriad intrinsic and extrinsic cues. In this review, we explore recent data elucidating the mechanobiological regulation of the volume of animal cells and its coordination with metabolic and proliferative pathways.