Background/Aims: Blocking the complement system is a promising strategy to impede the progression of metabolic dysfunction–associated steatotic liver disease (MASLD). However, the interplay between complement and MASLD remains to be elucidated. This comprehensive approach aimed to investigate the potential association between complement dysregulation and the histological severity of MASLD. Methods: Liver biopsy specimens were procured from a cohort comprising 106 Korean individuals, which included 31 controls, 17 with isolated steatosis, and 58 with metabolic dysfunction–associated steatohepatitis (MASH). Utilizing the Infinium Methylation EPIC array, thorough analysis of methylation alterations in 61 complement genes was conducted. The expression and methylation of nine complement genes in a murine MASH model were examined using quantitative RT-PCR and pyrosequencing. Results: Methylome and transcriptome analyses of liver biopsies revealed significant (p<0.05) hypermethylation and downregulation of C1R, C1S, C3, C6, C4BPA<, and SERPING1, as well as hypomethylation (p<0.0005) and upregulation (p<0.05) of C5AR1, C7, and CD59, in association with the histological severity of MASLD. Furthermore, DNA methylation and the relative expression of nine complement genes in a MASH diet mouse model aligned with human data. Conclusions Our research provides compelling evidence that epigenetic alterations in complement genes correlate with MASLD severity, offering valuable insights into the mechanisms driving MASLD progression, and suggests that inhibiting the function of certain complement proteins may be a promising strategy for managing MASLD.

Pembrolizumab is an immune checkpoint inhibitor that selectively blocks the programmed cell death (PD)-1 receptor. Although it has a dramatic effect on the treatment of advanced malignancies, instability of immune tolerance may cause immune-related adverse events in the skin. A 62-year-old male with a history of metastatic urothelial carcinoma was referred to the dermatology department and presented with a widespread mucocutaneous rash. Itching appeared 7 days after the first administration of pembrolizumab, and on the third day after the second administration, an erythematous maculopapular rash that coalesced into large flaccid bullae on the whole body with a positive Nikolsky’s sign developed. A biopsy revealed a subepidermal bulla with basal keratinocyte necrosis. Pembrolizumab was discontinued due to the diagnosis of toxic epidermal necrolysis (TEN), and intravenous methylprednisolone was started. Herein, we report a case of TEN induced by pembrolizumab to highlight immune-related cutaneous adverse events in patients receiving anti-PD-1 therapy.

Background: Patients with stable psoriasis showing clearear-clear response can consider extending the dosing interval of biologics. However, few studies have reported the treatment outcomes following irregular dosing intervals of biologics in patients with psoriasis. Objective: We compared treatment outcomes after regular and irregular dosing intervals of biologics in patients with psoriasis. Methods: This single-center, retrospective observational study included patients who received biologics for treatment of plaque psoriasis between January 1, 2014 and December 31, 2019. We compared patient demographics, clinical characteristics, biologics administered, and treatment outcomes based on the regularity of the dosing interval. Results: Among 95 patients investigated, 63 (66.3%) received biologics at regular dosing intervals. We observed no significant intergroup differences in the final Psoriasis Area Severity Index (PASI) scores (1.2 vs. 1.8, p=0.16) and in the percentage improvement in PASI scores from baseline levels (−89.8% vs. −90.8%, p=0.68). The rate at which biologics were switched was higher in the irregular-dosing group than in the regular-dosing group; however, the difference was statistically nonsignificant (28.1% vs. 12.7%, p=0.06). We observed a significant intergroup difference in patients who were administered guselkumab at baseline (12 [21.8%] vs. 0 [0.0%], p=0.01). Conclusion This study showed that compared with regular dosing intervals, irregular dosing intervals of biologics were associated with high rates of switching of these agents, although we observed no statistically significant differences with regard to PASI scores. Therefore, it is important to adhere to the standard dosing schedule prescribed for biologics, and guselkumab may improve patient compliance.

BACKGROUND: Various cell-culture systems have been used to evaluate drug toxicity in vitro. However, factors that affect cytotoxicity outcomes in drug toxicity evaluation systems remain elusive. In this study, we used multilayered sheets of cardiac-mimetic cells, which were reprogrammed from human fibroblasts, to investigate the effects of the layer number on drug cytotoxicity outcomes. METHODS: Cell sheets of cardiac-mimetic cells were fabricated by reprogramming of human fibroblasts into cardiacmimetic cells via coculture with cardiac cells and electric stimulation, as previously described. Double-layered cell sheets were prepared by stacking the cell sheets. The mono- and double-layered cell sheets were treated with 5-fluorouracil (5-FU), an anticancer drug, in vitro. Subsequently, apoptosis and lipid peroxidation were analyzed. Furthermore, effects of cardiacmimetic cell density on cytotoxicity outcomes were evaluated by culturing cells in monolayer at various cell densities. RESULTS: The double-layered cell sheets exhibited lower cytotoxicity in terms of apoptosis and lipid peroxidation than the mono-layered sheets at the same 5-FU dose. In addition, the double-layered cell sheets showed better preservation of mitochondrial function and plasma membrane integrity than the monolayer sheets. The lower cytotoxicity outcomes in the double-layered cell sheets may be due to the higher intercellular interactions, as the cytotoxicity of 5-FU decreased with cell density in monolayer cultures of cardiac-mimetic cells. CONCLUSION The layer number of cardiac-mimetic cell sheets affects drug cytotoxicity outcomes in drug toxicity tests.The in vitro. cellular configuration that more closely mimics the in vivo configuration in the evaluation systems seems to exhibit lower cytotoxicity in response to drug.

BACKGROUND: Ferroptosis is an iron-dependent, non-apoptotic programmed cell death. Cellular senescence contributes to aging and various age-related diseases through the expression of a senescence-associated secretory phenotype (SASP). Senescent cells are often resistant to ferroptosis via increased ferritin and impaired ferritinophagy. In this study, we investigated whether treatment with JQ1 could remove senescent cells by inducing ferroptosis. METHODS: Senescence of human dermal fibroblasts was induced in vitro by treating the cells with bleomycin. The senolytic effects of JQ1 were evaluated using a SA-β gal assay, annexin V analysis, cell counting kit-8 assay, and qRT-PCR. Ferroptosis following JQ1 treatment was evaluated with qRT-PCR and BODIPY staining. RESULTS: At a certain range of JQ1 concentrations, JQ1 treatment reduced the viability of bleomycin-treated cells (senescent cells) but did not reduce that of untreated cells (non-senescent cells), indicating that JQ1 treatment can selectively eliminate senescent cells. JQ1 treatment also decreased SASP expression only in senescent cells. Subsequently, JQ1 treatment reduced the expression of ferroptosis-resistance genes in senescent cells. JQ1 treatment induced lipid peroxidation in senescent cells but not in non-senescent cells. CONCLUSION The data indicate that JQ1 can eliminate senescent cells via ferroptosis. This study suggests ferroptosis as a new mechanism of senolytic therapy.

Background: Patients with stable psoriasis showing clearear-clear response can consider extending the dosing interval of biologics. However, few studies have reported the treatment outcomes following irregular dosing intervals of biologics in patients with psoriasis. Objective: We compared treatment outcomes after regular and irregular dosing intervals of biologics in patients with psoriasis. Methods: This single-center, retrospective observational study included patients who received biologics for treatment of plaque psoriasis between January 1, 2014 and December 31, 2019. We compared patient demographics, clinical characteristics, biologics administered, and treatment outcomes based on the regularity of the dosing interval. Results: Among 95 patients investigated, 63 (66.3%) received biologics at regular dosing intervals. We observed no significant intergroup differences in the final Psoriasis Area Severity Index (PASI) scores (1.2 vs. 1.8, p=0.16) and in the percentage improvement in PASI scores from baseline levels (−89.8% vs. −90.8%, p=0.68). The rate at which biologics were switched was higher in the irregular-dosing group than in the regular-dosing group; however, the difference was statistically nonsignificant (28.1% vs. 12.7%, p=0.06). We observed a significant intergroup difference in patients who were administered guselkumab at baseline (12 [21.8%] vs. 0 [0.0%], p=0.01). Conclusion This study showed that compared with regular dosing intervals, irregular dosing intervals of biologics were associated with high rates of switching of these agents, although we observed no statistically significant differences with regard to PASI scores. Therefore, it is important to adhere to the standard dosing schedule prescribed for biologics, and guselkumab may improve patient compliance.

BACKGROUND: Various cell-culture systems have been used to evaluate drug toxicity in vitro. However, factors that affect cytotoxicity outcomes in drug toxicity evaluation systems remain elusive. In this study, we used multilayered sheets of cardiac-mimetic cells, which were reprogrammed from human fibroblasts, to investigate the effects of the layer number on drug cytotoxicity outcomes. METHODS: Cell sheets of cardiac-mimetic cells were fabricated by reprogramming of human fibroblasts into cardiacmimetic cells via coculture with cardiac cells and electric stimulation, as previously described. Double-layered cell sheets were prepared by stacking the cell sheets. The mono- and double-layered cell sheets were treated with 5-fluorouracil (5-FU), an anticancer drug, in vitro. Subsequently, apoptosis and lipid peroxidation were analyzed. Furthermore, effects of cardiacmimetic cell density on cytotoxicity outcomes were evaluated by culturing cells in monolayer at various cell densities. RESULTS: The double-layered cell sheets exhibited lower cytotoxicity in terms of apoptosis and lipid peroxidation than the mono-layered sheets at the same 5-FU dose. In addition, the double-layered cell sheets showed better preservation of mitochondrial function and plasma membrane integrity than the monolayer sheets. The lower cytotoxicity outcomes in the double-layered cell sheets may be due to the higher intercellular interactions, as the cytotoxicity of 5-FU decreased with cell density in monolayer cultures of cardiac-mimetic cells. CONCLUSION The layer number of cardiac-mimetic cell sheets affects drug cytotoxicity outcomes in drug toxicity tests.The in vitro. cellular configuration that more closely mimics the in vivo configuration in the evaluation systems seems to exhibit lower cytotoxicity in response to drug.

BACKGROUND: Ferroptosis is an iron-dependent, non-apoptotic programmed cell death. Cellular senescence contributes to aging and various age-related diseases through the expression of a senescence-associated secretory phenotype (SASP). Senescent cells are often resistant to ferroptosis via increased ferritin and impaired ferritinophagy. In this study, we investigated whether treatment with JQ1 could remove senescent cells by inducing ferroptosis. METHODS: Senescence of human dermal fibroblasts was induced in vitro by treating the cells with bleomycin. The senolytic effects of JQ1 were evaluated using a SA-β gal assay, annexin V analysis, cell counting kit-8 assay, and qRT-PCR. Ferroptosis following JQ1 treatment was evaluated with qRT-PCR and BODIPY staining. RESULTS: At a certain range of JQ1 concentrations, JQ1 treatment reduced the viability of bleomycin-treated cells (senescent cells) but did not reduce that of untreated cells (non-senescent cells), indicating that JQ1 treatment can selectively eliminate senescent cells. JQ1 treatment also decreased SASP expression only in senescent cells. Subsequently, JQ1 treatment reduced the expression of ferroptosis-resistance genes in senescent cells. JQ1 treatment induced lipid peroxidation in senescent cells but not in non-senescent cells. CONCLUSION The data indicate that JQ1 can eliminate senescent cells via ferroptosis. This study suggests ferroptosis as a new mechanism of senolytic therapy.

Background: A healthy microbiome helps maintain the gut barrier and mucosal immune tolerance. Previously, we demonstrated that acute kidney injury (AKI) provoked dysbiosis, gut inflammation, and increased permeability. Here, we investigated the renoprotective effects of the probiotic Bifidobacterium bifidum BGN4 and the underlying mechanisms thereof. Methods: C57BL/6 mice were subjected to bilateral renal ischemia-reperfusion injury (IRI) or sham operation. In the probiotic-treated group, BGN4 was administered by gavage once daily, starting 2 weeks before injury. Results: Administration of BGN4 significantly increased gut microbiome diversity and prevented expansion of the Enterobacteriaceae and Bacteroidetes that were the hallmarks of AKI-induced dysbiosis. Further, BGN4 administration also significantly reduced other IRI-induced changes in the colon microenvironment, including effects on permeability, apoptosis of colon epithelial cells, and neutrophil and proinflammatory macrophage infiltration. Mononuclear cells co-cultured with BGN4 expressed significantly increased proportions of CD103+/CD11c+ and CD4+ CD25+ Treg cells, suggesting a direct immunomodulatory effect. BGN4 induced Treg expansion in colon, mesenteric lymph nodes (MNL), and kidney. BGN4 also reduced CX3CR1intermediateLy6Chigh monocyte infiltration and interleukin (IL)-17A suppression in the small intestine, which may have attenuated AKI severity, kidney IL-6 messenger RNA expression, and AKI-induced liver injury. Conclusion Prior supplementation with BGN4 significantly attenuated the severity of IRI and secondary liver injury. This renoprotective effect was associated with increased Foxp3 and reduced IL-17A expression in the colon, MNL, and kidney, suggesting that BGN4-induced immunomodulation might contribute to its renoprotective effects. Probiotics may therefore be a promising strategy to reduce AKI severity and/or remote organ injury.