Intestinal epithelial cells (IECs) play a crucial role in forming a protective barrier and regulating the absorption of substances passing through the small intestine. Disrupting the epithelial barrier function can result in intestinal diseases such as inflammatory bowel disease. Glyceraldehyde (GA)-derived advanced glycation end-products (AGEs) (toxic AGEs, TAGE) are AGEs formed by the nonenzymatic Maillard reaction. Although AGEs have been implicated in intestinal barrier breakdown, the associated mechanism remains underexplored. In this study, the effects of accumulated TAGE in IECs were investigated by focusing on tight junctions using Caco-2 cells—a human colorectal epithelial adenocarcinoma cell line. While GA treatment induced the formation of intracellular TAGE in Caco-2 cells, resulting in cell death, the generated intracellular TAGE triggered increased paracellular permeability. In addition, immunofluorescence staining showed that GA treatment decreased the fluorescence intensities of ZO-1 and claudin-7, which are tight junction proteins attached to the plasma membrane. Furthermore, an evaluation of the mechanism behind intestinal barrier breakdown revealed excessive reactive oxygen species (ROS) production and increased expression of reduced nicotinamide adenine dinucleotide phosphate (NAD(P)H) oxidase subunit genes, a mechanism of ROS production, in the GA-treated group compared with the control group. Furthermore, GA treatment induced necrosis and caused cytotoxicity in this condition. Overall, these results suggest that TAGE induction can disrupt tight junctions in IECs via cell injury as a pathway.

Placental extract (PE) is employed as a skin-whitening agent in Japan, where this material is used in cosmetics and dietary supplements. However, the mechanism of PE’s anti-melanogenic activity remains poorly understood. The goal of the present study was to elucidate the mechanism of PE’s inhibitory effect on melanogenesis in B16 murine melanoma cells. Specifically, the activity of equine PE (EPE) against tyrosinase and melanogenic proteins was evaluated. The effects of EPE on tyrosinase activity and melanin content were assessed spectrophotometrically. This analysis showed that EPE inhibits melanogenesis in melanoma cells in a dose-dependent manner without affecting cell proliferation. EPE did not directly inhibit the enzymatic activity of tyrosinase. Western blot analysis demonstrated that EPE exposure also led to decreases in the protein levels of tyrosinase and tyrosinase-related protein 1 (TRP-1) in melanoma cells, without affecting the levels of the mRNAs encoding these proteins. This analysis further demonstrated that the EPE-induced depletion of tyrosinase and TRP-1 resulted from the induction, by EPE, of proteasome-mediated proteolytic degradation. Notably, the EPE-induced depletion of tyrosinase and TRP-1 was prevented by joint exposure to EPE and the proteasome inhibitor MG132. Similar experiments showed that the exposure of melanoma cells to MG132 abrogates the inhibition of melanogenesis by EPE. Immunoprecipitation analysis further revealed that EPE induces the ubiquitination of tyrosinase and TRP-1. Taken together, these results suggested that EPE induces proteasomal degradation of tyrosinase and TRP-1 by enhancing the ubiquitination of these targets, leading to the depletion of these proteins and the inhibition of melanogenesis.

The human deubiquitinating enzyme ubiquitin-specific peptidase 7 (USP7) has emerged as a promising anti-tumor target, particularly in colorectal cancer, due to its regulation of the MDM2/p53 axis. Through a combination of ubiquitin C-terminal 7-amido-4-methylcoumarin hydrolysis assay and ubiquitin-propargylamide protease profiling, we identified the natural dietary flavonoid quercetin as a potent USP7 inhibitor in both cell-free and cellular contexts. Cellular thermal shift and surface plasmon resonance analyses demonstrated that quercetin is directly bound to USP7. Consistent with USP7 target engagement in cells, quercetin decreased MDM2 levels and subsequently increased the levels of p53. Moreover, quercetin also suppressed colorectal cancer cell proliferation by inducing G2/M cell cycle arrest and inhibiting cell migration. Collectively, our study identified quercetin as a novel and effective USP7 inhibitor with potent anti-colorectal cancer activity, highlighting its therapeutic potential for targeting the USP7–MDM2–p53 axis and warranting further exploration as a promising therapeutic agent in colorectal cancer treatment.

Chronic kidney disease (CKD) is a serious chemotherapy-associated clinical condition. CKD complicates the pharmacokinetics of anticancer drugs, requiring personalized dosing strategies to minimize toxicity. S-1 and oxaliplatin (the SOX regimen) are widely used for gastrointestinal cancer treatment. However, the specific association between systemic drug exposure and renal biomarker levels in CKD remains unclear. This study evaluated the pharmacokinetics of S-1 and oxaliplatin in 2 CKD model rats (5/6 nephrectomy and adenine-induced) and examined their relationships with renal biomarkers. S-1 (2 mg/kg as tegafur) and oxaliplatin (5 mg/kg) were administered separately, and plasma levels of tegafur, 5-fluorouracil (5-FU), 5-chloro-2,4-dihydropyridine, oxaliplatin, and platinum were measured by LC-tandem MS. Systemic exposure to S-1 and oxaliplatin was higher in the CKD model rats than in the normal group, with 5-FU levels being particularly higher in the adenine-induced model than in the 5/6 nephrectomy model. The area under the curve values of 5-FU and platinum were strongly correlated with plasma creatinine (P_Cr) levels (r = 0.79 and 0.88, respectively). Population pharmacokinetic analysis identified P_Cr as a significant covariate of 5-FU clearance. A nomogram constructed using P_Cr-based simulations demonstrated the feasibility of individualized S-1 dosing. Overall, our findings suggest that P_Cr is a practical biomarker to guide S-1 dose optimization and highlight the importance of pharmacokinetics-based strategies for patients with cancer and CKD.

Endometriosis, a prevalent gynecological disorder marked by ectopic growth of endometrial-like tissue, demonstrates malignant tumor-like properties including aggressive adhesion and invasiveness. Emerging evidence implicates roundabout guidance receptor 3 (ROBO3) in cellular pathophysiology, yet its role in endometriosis remains unexplored. In this study, we first found abnormally high ROBO3 expression in endometriosis by bioinformatics analysis. Next, functional assays revealed that ROBO3 is a key regulator promoting the invasion and migration of endometriotic stromal cells (ESCs) in vitro. Mechanistically, ROBO3 activates the Wnt/β-catenin signaling pathway, evidenced by increased phosphorylation of glycogen synthase kinase 3β, nuclear β-catenin accumulation, and upregulated c-myc expression. Pharmacological inhibition of Wnt/β-catenin with MSAB (5 μM) reversed ROBO3-mediated pro-invasive and pro-migratory effects. Furthermore, we discovered that ROBO3 enhances the secretion of chemokines CCL2 and CCL5 in ESCs, which subsequently promote macrophage polarization toward the M2 phenotype, as indicated through elevated expression of interleukin-10 and Arg-1. Collectively, our findings elucidate a dual mechanism whereby ROBO3 drives endometriosis progression through both intrinsic activation of Wnt/β-catenin signaling and extrinsic modulation of tumor-associated macrophages, underscoring ROBO3 as a promising therapeutic target for endometriosis.

He-Wei-Decoction (HWD), a traditional Chinese medicine formula, emphasizes “strengthening the spleen and supplementing qi (Jianpi Yiqi),” and “resolving stasis and detoxifying (Huayu Jiedu).” This formula has been utilized in the treatment of chronic atrophic gastritis (CAG), however, its precise mechanisms of action remain to be elucidated. This study integrates network pharmacology with molecular dockings to identify the underlying mechanisms of HWD in the treatment of CAG. Then, immunohistochemistry assay analyzed the gastric mucosal lesions before and after treatment with HWD in CAG patients. The efficacy and mechanism of key active compounds in the treatment of CAG were validated using a 1-methyl-3-nitro-1-nitrosoguanidine (MNNG)-induced GES-1 cell in vitro model. A total of 165 active compounds from HWD were identified, along with 169 targets associated with CAG. Gene oncology (GO) analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, and Component-Target-Pathway network analysis revealed that the Toll-like receptor (TLRs) signaling pathway may play a role in HWD’s regulation of inflammation in gastric mucosa. Molecular docking identified that luteolin, quercetin, and hederagenin potentially interact with key target proteins TLR4 and nuclear factor-kappaB (NF-κB). Experimental results validated that HWD significantly improved atrophic mucosa and inhibited the expression of TLR4, NF-κB, and cyclooxygenase 2 (COX2) proteins. The active compounds, luteolin, quercetin, and hederagenin, inhibit cell viability, migration and invasion, and reduce the expression of TLR4, NF-κB, and COX2. In summary, luteolin, quercetin, and hederagenin, the primary active components of HWD, can ameliorate the CAG by regulating the TLR4/NF-κB signaling pathway.

Puerariae Radix, the root of Pueraria lobata (Willd.) Ohwi is primarily used as a traditional herbal medicine in East Asia. Although phytochemical and biological investigations of the roots have been well-reported, those of the leaves are limited. To explore the potential value of P. lobata leaves, this study aimed to evaluate their effect on melanin synthesis in B16-F1 murine melanoma cells and three-dimensional (3D) human skin equivalents and investigate the underlying molecular mechanism. The leaf extract increased the melanin content in B16-F1 cells, with stronger induction potency than that of the vine and root extracts. Among the 4 fractions prepared from the leaf extract, the hexane fraction significantly induced melanin synthesis. Both the leaf extract and hexane fraction also increased melanin content in a 3D human skin equivalent model. Of the 7 fractions separated from the hexane fraction, fraction 1 (fr. 1) strongly induces melanin synthesis and intracellular tyrosinase activity. Further analysis indicated that fr. 1 may induce melanin synthesis via cAMP-responsive element-binding protein (CREB) phosphorylation and microphthalmia-associated transcription factor (MITF) expression, leading to the expression of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2. These results suggest that P. lobata leaves may be a useful medicinal resource for treating hypopigmentation.

Enhancing cardiomyocyte mitochondrial function has been reported as a potential therapeutic approach for various diseases. However, this is technically difficult, and its practical use has not been described. Although treatments such as exon skipping for skeletal muscle have been established for Duchenne muscular dystrophy (DMD), no curative treatment has been developed for DMD cardiomyopathy, and only cardioprotective medications and symptomatic treatments are available. In this study, we attempted to activate cardiac myocyte mitochondria via direct drug delivery using lipid nanoparticles and investigated the application of this strategy to diseased cells. First, we delivered CoQ₁₀, a mitochondrial activator with cellular antioxidant capacity, into mitochondria in H9C2 cells using MITO-Porter, a mitochondria-directed nanoparticle. Cellular MITO-Porter uptake was measured using flow cytometry. Co-localization of mitochondria and MITO-Porter was confirmed using confocal laser microscopy. Mitochondrial respiratory capacity was measured using an extracellular flux analyzer. Furthermore, the concentration–response relationships of the amount of nanoparticles or CoQ₁₀ with mitochondrial energy production capacity were confirmed. Next, we examined the possibility of improving mitochondrial energy production capacity in diseased cells. Cells were isolated from the myocardium of DMD model rats generated using the CRISPR-Cas9 system. Mitochondrial energy production capacity was lower in DMD primary cardiomyocytes than in wild-type primary cardiomyocytes. CoQ₁₀ delivery to mitochondria in DMD primary cardiomyocytes using MITO-Porter improved mitochondrial energy production capacity. Thus, enhanced cardiomyocyte mitochondrial energy production might represent a potential treatment for cardiomyopathy.

Studies on the effect of environmental chemicals on cancer has primarily focused on the early stages, while the impact on later stages, particularly cancer progression, has been less explored. Cellular senescence, a response to stress such as DNA damage and oxidative stress, has been reported to play a crucial role in cancer progression. Environmental chemicals are suspected to promote cancer progression, yet it is unclear whether this is mediated through cellular senescence. Benzo[a]pyrene (BP) is known to induce DNA damage, a key trigger of senescence, but whether it directly induces senescence in cancer cells remains uncertain. This study aims to evaluate the senescence-inducing potential of BP in breast cancer cells to better understand its role in cancer progression. We examined the effects of BP, a polycyclic aromatic hydrocarbon primarily generated via incomplete combustion of organic matter and commonly found in water, soil, automobile exhaust, and tobacco smoke, on MCF7 breast cancer cells. BP enters the human body via inhalation, ingestion, and dermal contact. Here, as indicated by multiple senescence markers, including nuclear elongation, senescence-associated β-galactosidase activity, DNA damage, and increased p21 expression, BP induced cellular senescence in MCF7 cells. As cellular senescence is associated with malignant cell transformation, our results might suggest that BP contributes to cancer progression by inducing cellular senescence.

The effect of transient receptor potential canonical-3 (TRPC3) channel inhibitor pyrazole-3 (Pyr3) on the stability of atrial fibrillation (AF) was analyzed in a rat model of chronic volume overload. Male Wistar rats underwent aorto-venocaval shunt (AVS) surgery and received Pyr3 treatment intraperitoneally for 12 weeks. Morphological and electrophysiological assessments were performed at the end of the treatment period. Longer P-wave duration, atrial conduction time, and AF duration, in addition to greater atrial tissue weight, were detected in AVS rats compared with sham rats. Chronic Pyr3 administration prevented AVS-induced prolongation of P-wave duration and atrial conduction time, partially prevented atrial weight increase, and abbreviated AVS-induced prolongation of AF duration to similar levels as those in sham rats, without affecting the atrial effective refractory period. These results suggest that the TRPC3 inhibitor Pyr3 can ameliorate sustained AF associated with chronic volume overload by improving atrial conduction defects in AVS rats. Pharmacological inhibition of TRPC3 channels by Pyr3 thus represents a promising therapeutic strategy for preventing AF development related to structural modeling.

Increased accumulation of extracellular matrix (ECM) in the trabecular meshwork (TM) causes a rise in intraocular pressure (IOP), which is a primary risk factor for glaucoma. Hyaluronan (HA) is essential for forming the ECM network, but it is unclear whether HA metabolism plays a role in IOP control. In this study, we focused on the hyaluronan-binding protein involved in hyaluronan depolymerization (HYBID, also referred to as cell migration inducing hyaluronidase 1 (CEMIP)/KIAA1199), which is an HA-degrading enzyme. Hybid knockout (KO) mice exhibited IOP elevation [IOP on average +2.14 mmHg at 7 weeks old, +1.54 mmHg at 8 weeks old vs. IOP of wildtype (WT) mice]. In addition, fibronectin and HA accumulated in the TM of Hybid KO mice. In cultured human TM cells (HTMCs), HYBID knockdown with HYBID siRNA increased HA and fibronectin protein but the expression of fibronectin mRNA was not altered. In addition, in HYBID knockdown HTMCs, matrix metalloproteinase (MMP)-1 and tissue inhibitor of metalloproteinase (TIMP) 3 were increased and MMP-9 was decreased. These results indicated that HYBID knockdown did not contribute to fibronectin production but inhibited ECM degradation through decreased MMP-9 expression and increased TIMP3 expression, leading to reduced MMP-2 and MMP-9 activity. These findings may offer new perspectives on the underlying mechanisms of glaucoma associated with fibrosis and potentially contribute to the development of novel glaucoma therapeutics.

We previously reported that CD8⁺ T cell activation via drug-induced altered self-presentation increases the tumor immunogenicity and cancer immunotherapy efficacy. Although the anti-human immunodeficiency virus drug abacavir (ABC) increases the tumor immunogenicity and induces CD8⁺ T cell anti-tumor immune responses in mice inoculated with tumor cells ectopically expressing the human leukocyte antigen (HLA)-B*57:01, whether such anti-tumor immunity is also triggered in hosts with high HLA-B*57:01 expression levels remain unclear. To verify this, we investigated the anti-tumor effects of ABC on HLA-B*57:01-expressing tumor and normal host cells using HLA-B*57:01 transgenic (B*57:01-Tg) mice in this study. ABC suppressed the HLA-B*57:01-expressing B16F10 tumor growth and increased the CD8⁺ T cell tumor infiltration in B*57:01-Tg mice. ABC also activated the tumor-infiltrating CD8⁺ T cells to secrete interferon-γ but did not promote their proliferation in the tumors of B*57:01-Tg mice. Moreover, ABC did not increase the effector CD8⁺ T cell proportions in the tumor-draining lymph nodes of B*57:01-Tg mice. Overall, CD8⁺ T cells preferentially recognized the ABC-induced altered self-antigen-presenting HLA-B*57:01-expressing tumor cells, but not host cells, to elicit anti-tumor immunity.

Qin Gui Huo Luo oral liquid (QGHL) is a modern formulation derived from the Traditional Chinese Medicine (TCM) Daqinjiao Decoction. QGHL has been widely adopted in China’s clinical settings as a therapeutic agent for microcirculatory dysfunction. However, the mechanistic interplay of QGHL in animal models for ischemic stroke (IS) treatment remains unexplored. This study aimed to investigate the impact of QGHL on blood–brain barrier (BBB) disruption induced by cerebral ischemia–reperfusion (I/R) injury. HPLC analysis was employed to identify the major chemical constituents of QGHL while maintaining stringent quality standards. Male C57BL/6J mice were subjected to 1-h right middle cerebral artery occlusion, followed by 24-h reperfusion to induce I/R injury. Subsequently, QGHL was administered intragastrically at 3 different doses (7.8, 15.6, and 31.2 g kg^–1). QGHL treatment significantly attenuated cerebral I/R injury, as evidenced by reduced infarct volume, improved neurological scores, attenuated cerebral edema, and restored cerebral blood flow. Moreover, QGHL preserved BBB integrity by upregulating zonula occludens-1 (ZO-1) and occludin while suppressing matrix metalloproteinase (MMP)-2/9 expression. Network pharmacology revealed that phosphatidylinositol 3-kinase (PI3K)/AKT/FOXO3A axis served as a major signaling pathway mediating QGHL’s therapeutic effects against IS, which was further confirmed by Western blot analysis. QGHL exerts neuroprotection against cerebral I/R injury in mice via modulation of the PI3K/AKT/FOXO3A signaling pathway, suggesting its potential as a novel therapeutic strategy for IS.

Oligodendroglia encompass oligodendrocyte precursor cells (OPCs) and oligodendrocytes (OLs). In the grey matter of the cortex, nearly all OPCs divide slowly, yet they do not differentiate solely into mature OLs, leaving the exact role of these OPCs in the grey matter enigmatic. Oligodendroglia were traced using the sex-determining region Y-related high mobility group-box 10 (Sox10) Cre-ER^T2 reporter mice. We compared the effect of tamoxifen dissolved in different solvents on the fate of Sox10 cells. We also compared the effect of tamoxifen dosage on the fate of Sox10 cells. The differentiation of labeled red fluorescent protein (RFP) cells was analyzed using immunofluorescence staining. Two groups of RFP cells, type A Sox10 (Sox10-A) cells and type B Sox10 (Sox10-B) cells, were identified in the cortex, striatum, hippocampus, thalamus, and hypothalamus. Sox10-A cells differentiate into platelet-derived growth factor receptor-β+, CD13+ pericytes, and smooth muscle myosin heavy chain 11+ smooth muscle cells when the mice received ethanol or high-dose tamoxifen. Sox10-B cells transform into glutamatergic neurons when the mice received high-dose tamoxifen. Sox10-B cells include perineuronal OPCs and OLs. This investigation provides evidence that a substantial proportion of oligodendroglia in the grey matter serve as mural cell precursors and neuronal precursors. These two phenomena may contribute to our understanding of the fate of oligodendroglia.

Fine bubbles (FBs), which are microscopic bubbles with a particle size less than 100 μm, have been increasingly utilized in industrial fields. They have been widely adopted across various industries including agriculture, fisheries, and cleaning. Furthermore, FBs are negatively charged colloids that can encapsulate various gases, leading to their potential use in the medical field. However, information on the biological safety of ultrafine bubbles (UFBs) remains limited. In particular, no safety evaluations of UFBs have been reported using internationally standardized protocols. Therefore, this study comprehensively evaluated the biological safety of air-UFB water that was measured, transported, and stored according to International Organization for Standardization (ISO) standards. To this end, in vitro skin irritation and eye irritation tests, as well as an in vivo 28-d repeated-dose oral toxicity test, were conducted in accordance with international protocols. The results of both in vitro tests showed that UFB water was classified as “Not classified” under the United Nations Globally Harmonized System of Classification and Labelling of Chemicals and was considered non-irritating and not seriously damaging to the skin or the eyes. Similarly, the abnormal changes attributable to the administration of UFB water were not observed in blood biochemistry and hematology tests, organ weights and histopathological evaluations on the in vivo test. These results, in which no toxicity attributable to UFBs was observed in dermal, ocular, or oral tests, support the fundamental safety of ISO-certified air-UFB water.

This study aimed to determine whether currently available medications for detrusor overactivity (DO) can inhibit the platelet-activating factor (PAF)-induced increase in the mechanical activity of the urinary bladder smooth muscle (UBSM) in guinea pigs. Ten clinically used DO drugs—oxybutynin, tolterodine, fesoterodine, propiverine, propantheline, solifenacin, imidafenacin, flavoxate, urapidil, and clenbuterol—were tested at a concentration of 10 μM, exceeding typical therapeutic plasma levels. Among these, oxybutynin exerted the most pronounced inhibitory effect, reducing the PAF (1 μM)-induced increase in basal tone by approximately 60%. Furthermore, oxybutynin (10 μM) also decreased 60 mM KCl-induced contractions by a similar extent and nearly abolished acetylcholine (ACh, 10 μM)-induced contractions. These findings suggest that oxybutynin suppresses PAF-induced UBSM hyperactivity through a mechanism distinct from its anticholinergic effect, likely mediated by blockade of voltage-dependent Ca²⁺ channels (VDCCs).

The extracellular matrix (ECM) is a noncellular component in all tissues and organs. Collagen, a component of the ECM, is the most abundant protein in the body. The amount of collagen decreases with aging, leading to wrinkles and skin sagging. Accelerated aging caused by UV radiation is known as photoaging. Skin fibroblasts exposed to UVB have reduced total collagen content due to accelerated production of collagen-degrading enzymes, matrix metalloproteinases (MMPs), and suppression of collagen production. However, the effects of UVB on the ECM surrounding the cell and its interaction with the cell have not been well reported. This study sought to elucidate the effects of UVB-induced changes in the extracellular environment on cells. UVB-irradiated collagen exhibited irradiation-dependent degradation and accelerated carbonylation, resulting in qualitative changes. UVB-induced changes in collagen led to reduced cell-collagen interactions, such as adhesion, proliferation, and contraction. Moreover, UVB-irradiated collagen was more susceptible to collagen degradation by MMP-1. UVB-induced changes in collagen were analyzed using mass spectrometry (LC-MS/MS). Although alternation of post-translational modification was not detected in the cell-bound regions of collagen, multiple sites of carbonylative modification were detected on proline (Pro), arginine (Arg), and lysine (Lys). The numerous carbonylative modifications to Pro, Arg, and Lys in collagen may cause changes in the overall structure of collagen and affect cellular functions that are regulated by the interaction with collagen. Overall, our findings highlight a photoaging mechanism that focuses on the effects of ECM changes on cells.

Resistance to thyroid hormone-β (RTHβ) is caused by mutations in thyroid hormone receptors (TRs), with palpitations, tachycardia, and/or goiter being the most frequently reported clinical features. In recent years, several synthetic thyromimetics have been developed to target mutations associated with RTHβ. Resmetirom, which was granted an accelerated approval by the U.S. Food and Drug Administration, is a TRβ-agonist for the first line therapy for metabolic dysfunction-associated steatohepatitis. This study aimed to evaluate the potential mechanisms of action of resmetirom on RTHβ through co-factors and association with clinical manifestations. We selected cases from 13 clinical records based on recently reported domestic cases in Japan. Based on these clinical reports, we conducted screenings using clinical symptoms, laboratory findings, and mutation data. We attempted to unveil the interaction between 26 RTHβ mutants and resmetirom focusing on recruitment of co-factors. Among the 26 probands, dominant-negative effects (DNE) were identified in 12 mutant TRs (48.5 ± 11.8%). Resmetirom was involved in the recruitment of the co-activators, steroid receptor coactivator-1 and glucocorticoid receptor-interacting protein-1, as well as the co-repressors (CoRs), nuclear-CoR and silencing mediator of retinoic acid and TR. Co-factor recruitment by resmetirom was detected in all mutants. In eight patients with DNE, an association between transcriptional activity and clinical symptoms was observed, which were the reasons for clinical investigation. Notably, in the helix-12 mutant-P453, mild induction of DNE was associated with the recruitment of CoRs, suggesting that resmetirom may be effective in alleviating subjective symptoms in mutants with attenuated DNE located in helix-12.

An elderly woman taking lacosamide (LCM) for epilepsy was diagnosed with tuberculous pleurisy. In the hospital, she received a four-drug combination therapy with rifampicin (RFP), isoniazid, pyrazinamide, and ethambutol for tuberculous pleurisy, in addition to medications for symptomatic epilepsy. At admission, her renal function was mildly impaired but remained stable throughout hospitalization. Serum albumin levels were slightly below the normal range. C-reactive protein was markedly elevated on day 4 but returned to normal by the time of discharge. On day 4, therapeutic drug monitoring (TDM) was initiated for LCM, a substrate for CYP2C19 and P-glycoprotein, because RFP can induce multiple cytochrome P450s (CYPs) and P-glycoprotein. Initially, the doses of RFP and LCM were 450 and 100 mg/d, respectively, and the serum concentration of LCM was 9.5 μg/mL (day 4). On day 12, the serum concentration of LCM decreased to 4.1 μg/mL, and the dose of LCM was increased to 200 mg/d. The dose of LCM was further increased to 300 mg/d on day 60 to maintain the serum concentration of LCM at approximately 10 μg/mL. The estimated serum concentration (C) of LCM normalized by the dose (D) ratio, or C/D ratio, was 0.095 on day 4 and decreased to 0.03–0.04 after day 12. The LCM concentration during RFP co-administration may have been affected by the combined effects of RFP-mediated CYP2C19 and P-glycoprotein induction, the patient’s inflammatory status, and concomitant anti-tuberculosis drugs. TDM is necessary to attain clinically effective serum concentrations of LCM when RFP is used concomitantly.