Trichloroisocyanuric Acid (TCIC), A Swimming Pool Disinfectant: New Developments and Role in UV-Induced Skin Inflammation

N-benzyl-N-methyldecane-1-amine derived from garlic ameliorates UVB-induced photoaging in HaCaT cells and SKH-1 hairless mice

Skin tissue is susceptible to oxidative stress-induced senescence provoked by ultraviolet (UV) exposure in our daily lives, resulting in photoaging. Herein, we explore whether N-benzyl-N-methyldecan-1-amine (BMDA) derived from garlic ameliorates UVB-induced photoaging. To address this issue, HaCaT keratinocytes were exposed to UVB irradiation under BMDA treatment. The presence of BMDA substantially reduced UVB-induced ROS levels in a dose-dependent manner. BMDA administration counteracted UVB-induced senescence in the β-galactosidase assay. Treatment with BMDA also rescued UVB-exposed cells (S phase; from 18.3 to 25.8%) from cell cycle arrest, similar to the level observed in untreated normal cells. These findings might support our observation that elevated levels of γ-H2AX, a DNA damage marker, under UVB exposure were reduced following BMDA administration. Additionally, BMDA treatment indirectly reduced UVB-induced melanin synthesis in melanocytes since BMDA failed to inhibit tyrosinase activity, a crucial enzyme in melanin synthesis. The topical application of BMDA on the skin of SKH-1 hairless mice also diminished wrinkle formation, supported by recovered collagen levels and the thickness of the epidermis and dermis, compared to those of UVB-control mice. Finally, the BMDA treatment diminished the expression of inflammatory cytokine transcripts such as TNF-α, IL-1β, IL-4, and IL-6 in the UVB-exposed skin tissues. This finding is further supported by Immunofluorescence microscopy, which showed a decrease in the expression of TNF-α, and IL-1β during BMDA treatment. Altogether, as BMDA mitigates UVB-induced photoaging by reducing ROS production, protecting against DNA damage, and suppressing inflammatory cytokine production, it has been proposed as an effective anti-photoaging molecule.

Exposure to chlorinated drinking water alters the murine fecal microbiota

An abundant body of scientific studies and regulatory guidelines substantiates antimicrobial efficacy of freshwater chlorination ensuring drinking water safety in large populations worldwide. In contrast to the purposeful use of chlorination ensuring antimicrobial safety of drinking water, only a limited body of research has addressed the molecular impact of chlorinated drinking water exposure on the gut microbiota. Here, for the first time, we have examined the differential effects of drinking water regimens stratified by chlorination agent [inorganic (HOCl) versus chloramine (TCIC)] on the C57BL/6J murine fecal microbiota. To this end, we exposed C57BL/6J mice to chlorinated drinking water regimens followed by fecal bacterial microbiota analysis at the end of the three-week feeding period employing 16S rRNA sequencing. α-diversity was strongly reduced when comparing chlorinated versus control drinking water groups and community dissimilarities (β-diversity) were significant between groups even when comparing HOCl and TCIC. We detected significant differences in fecal bacterial composition as a function of drinking water chlorination observable at the phylum and genus levels. Differential abundance analysis of select amplicon sequence variants (ASVs) revealed changes as a function of chlorination exposure [up: Lactobacillus ASV1; Akkermansia muciniphila ASV7; Clostridium ss1 ASV10; down: Ileibacterium valens ASV5; Desulfovibrio ASV11; Lachnospiraceae UCG-006 ASV15]. Given the established complexity of murine and human gastrointestinal microbiota and their role in health and disease, the translational relevance of the chlorination-induced changes documented by us for the first time in the fecal murine microbiota remains to be explored.

Transcriptome profiling reveals ethylene formation in rice seeds by trichloroisocyanuric acid

KEY MESSAGE

Ethylene formation via methionine reacting with trichloroisocyanuric acid under FeSO4 condition in a non-enzymatical manner provides one economically and efficiently novel ethylene-forming approach in planta. Rice seed germination can be stimulated by trichloroisocyanuric acid (TCICA). However, the molecular basis of TCICA in stimulating rice seed germination remains unclear. In this study, the molecular mechanism on how TCICA stimulated rice seed germination was examined via comparative transcriptome. Results showed that clustering of transcripts of TCICA-treated seeds, water-treated seeds, and dry seeds was clearly separated. Twenty-two and three hundred differentially expressed genes were identified as TCICA treatment responsive genes and TCICA treatment potentially responsive genes, respectively. Two and one TCICA treatment responsive genes were involved in ethylene signal transduction and iron homeostasis, respectively. Seventeen of the three hundred TCICA treatment potentially responsive genes were significantly annotated to iron ion binding. Meanwhile, level of methionine (ethylene precursor) showed a 73.9% decrease in response to TCICA treatment. Ethylene was then proved to produce via methionine reacting with TCICA under FeSO4 condition in vitro. Revealing ethylene formation by TCICA not only may bring novel insights into crosstalk between ethylene and other phytohormones during rice seed germination, but also may provide one economically and efficiently novel approach to producing ethylene in planta independently of the ethylene biosynthesis in plants and thereby may broaden its applications in investigational and applied purposes.