The role of histological subtype and chemotherapy on prognosis of ureteral cancer.

OBJECTIVE: To date, there have been few studies examining the prognostic implications of histological subtypes in ureteral cancer. And chemotherapy plays a crucial role in the treatment of ureteral cancer, while many factors influence the efficacy of chemotherapy. This study aimed to utilize the Surveillance, Epidemiology and End Results database to assess the impact of histological type on ureteral cancer prognostic outcomes and discovered how histological type and T-stage influence the efficacy of chemotherapy. METHODS: Based on Surveillance, Epidemiology, and End Results Program, we reviewed 8915 records of patients with primary ureteral cancer from 18 centers between 2000 and 2018. We focused on the overall survival and cancer-specific survival of the records and used Kaplan‒Meier method to calculate survival curves. RESULTS: In the comparison of prognostic outcomes, atypical subtypes exhibited a less favorable prognosis compared to typical ureteral carcinoma. Notably, patients diagnosed with papillary urothelial carcinoma demonstrated the most favorable overall survival (p = 0.005). Statistically significant benefits were observed in the prognosis of patients with non-papillary urothelial carcinoma who received chemotherapy (HR = 0.860, 95% CI 0.764-0.966, p = 0.011), while chemotherapy did not yield a statistically significant effect on the prognosis of patients with papillary urothelial carcinoma (HR = 1.055, 95% CI 0.906-1.228, p = 0.493). Chemotherapy had an adverse impact on the prognosis of patients with T1 ureteral cancer (HR = 1.235, 95% CI 1.016-1.502, p = 0.034), whereas it exhibited a positive prognostic effect for T3/T4 cases (HR = 0.739, 95% CI 0.654-0.835, p < 0.001). CONCLUSIONS: Histological type affects the prognosis of ureteral cancer. And evaluation of cancer histological type and T stage in ureteral cancer patients prior to chemotherapy is mandatory.

Inhibition of MFN1 restores tamoxifen-induced apoptosis in resistant cells by disrupting aberrant mitochondrial fusion dynamics.

Tamoxifen (TAM) resistance presents a major clinical obstacle in the management of estrogen-sensitive breast cancer, highlighting the need to understand the underlying mechanisms and potential therapeutic approaches. We showed that dysregulated mitochondrial dynamics were involved in TAM resistance by protecting against mitochondrial apoptosis. The dysregulated mitochondrial dynamics were associated with increased mitochondrial fusion and decreased fission, thus preventing the release of mitochondrial cytochrome c to the cytoplasm following TAM treatment. Dynamin-related GTPase protein mitofusin 1 (MFN1), which promotes fusion, was upregulated in TAM-resistant cells, and high MFN1 expression indicated a poor prognosis in TAM-treated patients. Mitochondrial translocation of MFN1 and interaction between MFN1 and mitofusin 2 (MFN2) were enhanced to promote mitochondrial outer membrane fusion. The interaction of MFN1 and cristae-shaping protein optic atrophy 1 (OPA1) and OPA1 oligomerization were reduced due to augmented OPA1 proteolytic cleavage, and their apoptosis-promoting function was reduced due to cristae remodeling. Furthermore, the interaction of MFN1 and BAK were increased, which restrained BAK activation following TAM treatment. Knockdown or pharmacological inhibition of MFN1 blocked mitochondrial fusion, restored BAK oligomerization and cytochrome c release, and amplified activation of caspase-3/9, thus sensitizing resistant cells to apoptosis and facilitating the therapeutic effects of TAM both in vivo and in vitro. Conversely, overexpression of MFN1 alleviated TAM-induced mitochondrial apoptosis and promoted TAM resistance in sensitive cells. These results revealed that dysregulated mitochondrial dynamics contributes to the development of TAM resistance, suggesting that targeting MFN1-mediated mitochondrial fusion is a promising strategy to circumvent TAM resistance.

The disordered extracellular matrix landscape induced endometrial fibrosis of sheep: A multi-omics integrative analysis.

Endometrial fibrosis leads to the destruction of endometrial function and affects reproductive performance. However, mechanisms underlying the development of endometrial fibrosis in sheep remain unclear. We use transcriptomic, proteomic, and metabolomic studies to reveal the formation mechanisms of endometrial fibrosis. The results showed that the fibrotic endometrial tissue phenotype presented fewer glands, accompanied by collagen deposition. Transcriptomic results indicated alterations in genes associated with the synthesis and degradation of extracellular matrix components, which alter metabolite homeostasis, especially in glycerophospholipid metabolism. Moreover, differentially expressed metabolites may play regulatory roles in key metabolic processes during fibrogenesis, including protein digestion and absorption, and amino acid synthesis. Affected by the aberrant genes, protein levels related to the extracellular matrix components were altered. In addition, based on Kyoto Encyclopedia of Genes and Genomes analysis of differentially expressed genes, metabolites and proteins, amino acid biosynthesis, glutathione, glycerophospholipid, arginine and proline metabolism, and cell adhesion are closely associated with fibrogenesis. Finally, we analyzed the dynamic changes in serum differential metabolites at different time points during fibrosis. Taken together, fibrosis development is related to metabolic obstacles in extracellular matrix synthesis and degradation triggered by disturbed gene and protein levels.

Dynamics and regulatory role of circRNAs in Asian honey bee larvae following fungal infection.

Non-coding RNA (ncRNA) plays a vital part in the regulation of immune responses, growth, and development in plants and animals. Here, the identification, characteristic analysis, and molecular verification of circRNAs in Apis cerana cerana worker larval guts were conducted, followed by in-depth investigation of the expression pattern of larval circRNAs during Ascosphaera apis infection and exploration of the potential regulatory part of differentially expressed circRNAs (DEcircRNAs) in host immune responses. A total of 3178 circRNAs in the larval guts of A. c. cerana were identified, with a length distribution ranging from 15 to 96,007 nt. Additionally, 155, 95, and 86 DEcircRNAs were identified in the in the 4-, 5-, and 6-day-old larval guts following A. apis infection. These DEcircRNAs were predicted to target 29, 25, and 18 parental genes relevant to 12, 20, and 17 GO terms as well as 144, 114, and 61 KEGG pathways, including 5 cellular and 4 humoral immune pathways. Complex competing endogenous RNA (ceRNA) regulatory networks were detected as being formed among DEcircRNAs, DEmiRNAs, and DEmRNAs. The target DEmRNAs were engaged in 36, 47, and 47 GO terms as well as 331, 332, and 331 pathways, including 6 cellular and 6 humoral immune pathways. Further, 19 DEcircRNAs, 5 DEmiRNAs, and 3 mRNAs were included in the sub-networks relative to 3 antioxidant enzymes. Finally, back-splicing sites within 15 circRNAs and the difference in the 15 DEcircRNAs' expression between uninoculated and A. apis-inoculated larval guts were confirmed based on molecular methods. These findings not only enrich our understanding of bee host-fungal pathogen interactions but also lay a foundation for illuminating the mechanism underlying the DEcircRNA-mediated immune defense of A. c. cerana larvae against A. apis invasion. KEY POINTS: • The expression pattern of circRNAs was altered in the A. cerana worker larval guts following A. apis infection. • Back-splicing sites within 15 A. cerana circRNAs were verified using molecular approaches. DEcircRNAs potentially modulated immune responses and antioxidant enzymes in A. apis-challenged host guts.

Mechanisms by which sheep milk consumption ameliorates insulin resistance in high-fat diet-fed mice.

Sheep milk is rich in fat, protein, vitamins and minerals and is also one of the most important sources of natural bioactives. Several biopeptides in sheep milk have been reported to possess antibacterial, antiviral and anti-inflammatory properties, and they may prevent type 2 diabetes (T2D), disease and cancer. However, the precise mechanism(s) underlying the protective role of sheep milk against T2D development remains unclear. Therefore, in the current study, we investigated the effect of sheep milk on insulin resistance and glucose intolerance in high-fat diet (HFD)-fed mice, by conducting intraperitoneal glucose tolerance tests, metabolic cage studies, genomic sequencing, polymerase chain reaction, and biochemical assays. Hyperinsulinemic-euglycemic clamp-based experiments revealed that mice consuming sheep milk exhibited lower hepatic glucose production than mice in the control group. These findings further elucidate the mechanism by which dietary supplementation with sheep milk alleviates HFD-induced systemic glucose intolerance.

Shikonin reverses cancer-associated fibroblast-induced gemcitabine resistance in pancreatic cancer cells by suppressing monocarboxylate transporter 4-mediated reverse Warburg effect.

BACKGROUND: Gemcitabine is a first-line chemotherapeutic agent for pancreatic cancer (PC); however, most patients who receive adjuvant gemcitabine rapidly develop resistance and recurrence. Cancer-associated fibroblasts (CAFs) are a crucial component of the tumor stroma that contribute to gemcitabine-resistance. There is thus an urgent need to find a novel therapeutic strategy to improve the efficacy of gemcitabine in PC cells under CAF-stimulation. PURPOSE: To investigate if shikonin potentiates the therapeutic effects of gemcitabine in PC cells with CAF-induced drug resistance. METHODS: PC cell-stimulated fibroblasts or primary CAFs derived from PC tissue were co-cultured with PC cells to evaluate the ability of shikonin to improve the chemotherapeutic effects of gemcitabine in vitro and in vivo. Glucose uptake assay, ATP content analysis, lactate measurement, real-time PCR, immunofluorescence staining, western blot, and plasmid transfection were used to investigate the underlying mechanism. RESULTS: CAFs were innately resistant to gemcitabine, but shikonin suppressed the PC cell-induced transactivation and proliferation of CAFs, reversed CAF-induced resistance, and restored the therapeutic efficacy of gemcitabine in the co-culture system. In addition, CAFs underwent a reverse Warburg effect when co-cultured with PC cells, represented by enhanced aerobic glycolytic metabolism, while shikonin reduced aerobic glycolysis in CAFs by reducing their glucose uptake, ATP concentration, lactate production and secretion, and glycolytic protein expression. Regarding the mechanism underlying these sensitizing effects, shikonin suppressed monocarboxylate transporter 4 (MCT4) expression and cellular membrane translocation to inhibit aerobic glycolysis in CAFs. Overexpression of MCT4 accordingly reversed the inhibitory effects of shikonin on PC cell-induced transactivation and aerobic glycolysis in CAFs, and reduced its sensitizing effects. Furthermore, shikonin promoted the effects of gemcitabine in reducing the growth of tumors derived from PC cells and CAF co-inoculation in BALB/C mice, with no significant systemic toxicity. CONCLUSION: These results indicate that shikonin reduced MCT4 expression and activation, resulting in inhibition of aerobic glycolysis in CAFs and overcoming CAF-induced gemcitabine resistance in PC. Shikonin is a promising chemosensitizing phytochemical agent when used in combination with gemcitabine for PC treatment. The results suggest that disrupting the metabolic coupling between cancer cells and stromal cells might provide an attractive strategy for improving gemcitabine efficacy.

Endoplasmic reticulum stress exacerbates microplastics-induced toxicity in animal cells.

Human and animal exposure to microplastics (MPs) contained in food is inevitable because of their widespread existence in the environment. Nevertheless, MPs toxicity studies in ruminants often lack attention. Here, we assessed the cytotoxicity of polystyrene microplastics (PS MPs) on goat mammary epithelial cells (GMECs). Compared to controls, PS MPs treatment significantly reduced cell viability, altered cell morphology and disrupted organelle integrity. Detection of membrane potential and reactive oxygen species (ROS) suggested that PS MPs induced mitochondrial dysfunction and oxidative stress. Further transcriptome analysis also confirmed alterations in these pathways. In addition, several genes related to endoplasmic reticulum (ER) homeostasis were significantly regulated in the transcriptional profile. Subsequent experiments confirmed that PS MPs induce ER stress via the PERK/eIF2α/CHOP pathway, accompanied by intracellular Ca2+ overload. Meanwhile, downstream activation of the Bax/Bcl-2 pathway and caspase cascade released apoptotic signals, which led to apoptosis in GMECs. Interestingly, the addition of PERK inhibitor (ISRIB) attenuated PS MPs-induced ER stress and apoptosis, which suggests that ER stress may exacerbate PS MPs-induced cytotoxicity. This work reveals the impact of MPs on mammalian cytotoxicity, enriches the mechanisms for the toxicity of MPs, and provides insight for further assessment of the risk of MPs in food.

Three versus four cycles of neoadjuvant chemotherapy for muscle-invasive bladder cancer: a systematic review and meta-analysis.

OBJECTIVE: The optimal cycle of neoadjuvant chemotherapy (NAC) for muscle-invasive bladder cancer (MIBC) remains controversial. This study aimed to compare the efficacy of three and four cycles of NAC in the treatment of MIBC through a systematic review and meta-analysis of the literature. MATERIALS AND METHODS: Relevant studies were systematically collected and reviewed in PubMed, Medline, Embase, Web of Science Databases, and the Cochrane Library. Relative ratios (RRs), Hazard ratios (HRs) and their 95% confidence intervals (CIs) were used to estimate outcome measures. Studies comparing the pathological response and prognosis of three versus four cycles of NAC for MIBC were included. RESULTS: Five studies were included in this meta-analysis, including 2190 patients, of whom 1016 underwent three cycles of NAC and 1174 underwent four cycles of NAC. All studies were retrospective cohort studies. We found that 4 cycles of NAC had significantly better cancer-specific survival than 3 cycles (HR = 1.31, 95%CI,1.03-1.67, p = 0.029). There was no significant difference in overall survival between patients who received 3 and 4 cycles of chemotherapy (HR = 1.18, 95%CI = 0.83-1.69, p = 0.345). Similarly, no significant difference was observed in pathological objective response (RR = 0.95, 95%CI= 0.81-1.11, p = 0.515) and complete response rates (RR = 0.87, 95%CI = 0.69-1.11, p = 0.256) in MIBC after 3 or 4 cycles of NAC. CONCLUSIONS: Three and four cycles of NAC had similar pathological responses and prognosis for MIBC, although the cancer-specific survival rate of four cycles was better than that of three cycles.

The pathological response rate and overall survival of three and four cycles of neoadjuvant chemotherapy for muscle-invasive bladder cancer were similar.Four cycles of neoadjuvant chemotherapy may improve the cancer-specific survival of patients with muscle-invasive bladder cancerIt is reasonable and feasible for clinicians to use three or four cycles of neoadjuvant chemotherapy.

First Characterization and Regulatory Function of piRNAs in the Apis mellifera Larval Response to Ascosphaera apis Invasion.

piRNAs are a class of small non-coding RNAs that play essential roles in modulating gene expression and abundant biological processes. To decode the piRNA-regulated larval response of western honeybees (Apis mellifera) to Ascosphaera apis infection, the expression pattern of piRNAs in Apis mellifera ligustica larval guts after A. apis inoculation was analyzed based on previously obtained high-quality small RNA-seq datasets, followed by structural characterization, target prediction, regulatory network investigation, and functional dissection. Here, 504, 657, and 587 piRNAs were respectively identified in the 4-, 5-, and 6-day-old larval guts after inoculation with A. apis, with 411 ones shared. These piRNAs shared a similar length distribution and first base bias with mammal piRNAs. Additionally, 96, 103, and 143 DEpiRNAs were detected in the 4-, 5-, and 6-day-old comparison groups. Targets of the DEpiRNAs were engaged in diverse pathways such as the phosphatidylinositol signaling system, inositol phosphate metabolism, and Wnt signaling pathway. These targets were involved in three energy metabolism-related pathways, eight development-associated signaling pathways, and seven immune-relevant pathways such as the Jak-STAT signaling pathway. The expression trends of five randomly selected DEpiRNAs were verified using a combination of RT-PCR and RT-qPCR. The effective overexpression and knockdown of piR-ame-945760 in A. apis-infected larval guts were achieved by feeding a specific mimic and inhibitor. Furthermore, piR-ame-945760 negatively regulated the expression of two target immune mRNAs, SOCS5 and ARF1, in the larval gut during the A. apis infection. These findings indicated that the overall expression level of piRNAs was increased and the expression pattern of piRNAs in larval guts was altered due to the A. apis infection, DEpiRNAs were putative regulators in the A. apis-response of A. m. ligustica worker larvae. Our data provide not only a platform for the functional investigation of piRNAs in honeybees, especially in bee larvae, but also a foundation for illuminating the piRNA-involved mechanisms underlying the host response to the A. apis infection.

[Stapled anoplin peptide combined with photothermal therapy enhances oncolytic immunotherapy of triple-negative breast cancer].

This study constructed a nano-drug delivery system, A3@GMH, by co-delivering the stapled anoplin peptide(Ano-3, A3) with the light-harvesting material graphene oxide(GO), and evaluated its oncolytic immunotherapy effect on triple-negative breast cancer(TNBC). A3@GMH was prepared using an emulsion template method and its physicochemical properties were characterized. The in vivo and in vitro photothermal conversion abilities of A3@GMH were investigated using an infrared thermal imager. The oncoly-tic activity of A3@GMH against TNBC 4T1 cells was evaluated through cell counting kit-8(CCK-8), lactate dehydrogenase(LDH) release, live/dead cell staining, and super-resolution microscopy. The targeting properties of A3@GMH on 4T1 cells were assessed using a high-content imaging system and flow cytometry. In vitro and in vivo studies were conducted to investigate the antitumor mechanism of A3@GMH in combination with photothermal therapy(PTT) through inducing immunogenic cell death(ICD) in 4T1 cells. The results showed that the prepared A3@GMH exhibited distinct mesoporous and coated structures with an average particle size of(308.9±7.5) nm and a surface potential of(-6.79±0.58) mV. The encapsulation efficiency and drug loading of A3 were 23.9%±0.6% and 20.5%±0.5%, respectively. A3@GMH demonstrated excellent photothermal conversion ability and biological safety. A3@GMH actively mediated oncolytic features such as 4T1 cell lysis and LDH release, as well as ICD effects, and showed enhanced in vitro antitumor activity when combined with PTT. In vivo, A3@GMH efficiently induced ICD effects with two rounds of PTT, activated the host's antitumor immune response, and effectively suppressed tumor growth in 4T1 tumor-bearing mice, achieving an 88.9% tumor inhibition rate with no apparent toxic side effects. This study suggests that the combination of stapled anoplin peptide and PTT significantly enhances the oncolytic immunotherapy for TNBC and provides a basis for the innovative application of anti-tumor peptides derived from TCM in TNBC treatment.

Camel milk peptides alleviate hyperglycemia by regulating gut microbiota and metabolites in type 2 diabetic mice.

This study aimed to investigate the hypoglycemic effect of Camel milk peptides (CMPs) on Type 2 diabetes mellitus (T2DM) mice and reveal its related mechanism from the aspect of gut microbiota and metabolites. The administering CMPs significantly alleviated the weight loss, polydipsia and polyphagia, reduced fasting blood glucose (FBG), improved insulin resistance and sensitivity, and restored the level of serum hormones, lipopolysaccharide (LPS), lipid metabolic and tissue damage. Furthermore, CMPs intervention remarkably reversed gut microbiota dysbiosis in T2DM mice by reducing the relative abundance of Proteobacteria, Allobaculum, Clostridium, Shigella and the Firmicutes/Bacteroidetes ratio, while increasing the relative abundance of Bacteroidetes and Blautia. Metabolomic analysis identified 84 different metabolites between T2DM and CMPs-treated groups, participating in three pathways of Pantothenate and CoA biosynthesis, Phenylalanine metabolism and Linoleic acid metabolism. Ureidopropionic acid, pantothenic acid, hippuric acid, hydrocinnamic acid and linoleic acid were identified as key acidic metabolites closely related to hypoglycemic effect. Correlation analysis indicated that CMPs might have a hypoglycemic effect through their impact on gut microbiota, leading to variations in short-chain fatty acids (SCFAs), acidic metabolites and metabolic pathways. These findings suggest that CMPs could be a beneficial nutritional supplement for intervention T2DM.

Genital mycoplasma infection: a systematic review and meta-analysis.

BACKGROUND: Recent studies have suggested that genital mycoplasma infections may be associated with male infertility. However, this association remains controversial due to time lapse, sample size, and regional prevalence. OBJECTIVES: This study aimed to systematically evaluate the relationship between genital mycoplasma and male infertility through a meta-analysis and to provide a basis for the clinical management of male infertility. METHODS: We conducted a search on PubMed, EMBASE, the Cochrane Library, and CNKI databases, from January 2000 to June 2023 to identify case-control studies on the interrelationship between genital mycoplasma infection and male infertility. Two independent researchers performed an assessment of the methodological quality of trials according to the Newcastle-Ottawa scale and extracted data strictly based on the inclusion and exclusion criteria, and afterward, we carried out a meta-analysis using Stata 16.0. Pooled odds ratios (OR) with 95% confidence intervals (CI) were used to assess this relationship. RESULTS: This meta-analysis included 21 studies from seven countries with a total of 53025 infertility cases and 6435 controls; the age range of the participating men was from 20 to 59 years old. The results obtained showed a higher prevalence of M. genitalium, M. hominis and U. urealyticum infections in infertile men than in the controls, with the opposite result for U. parvum (M. genitalium, OR, 3.438 [95% CI: 1.780, 6.643], with P = 0.000; M. hominis, OR, 1.840 [95% CI: 1.013, 3.343], with P = 0.045; U. urealyticum, OR, 3.278 [95% CI: 2.075, 5.180], with P = 0.000; U. parvum, OR, 1.671 [95% CI: 0.947, 2.950], with P = 0.077). Further, two subgroup analyses also showed that M. hominis and U. urealyticum infections were strongly associated with male infertility in China (M. hominis, P = 0.009; U. urealyticum, P = 0.000); however, M. hominis and U. urealyticum infection was not strongly associated with male infertility worldwide (M. hominis, P = 0.553; U. urealyticum, P = 0.050). CONCLUSION: This meta-analysis revealed that male infertility was significantly associated with M. genitalium, M. hominis and U. urealyticum infections, while U. parvum infection was not. Further, our study showed that genital mycoplasma infection influences male infertility and provides a basis for future treatment.

Comprehensive investigation of milk oligosaccharides in different mammalian species and the effect of breed and lactation period on sheep milk oligosaccharides.

Milk oligosaccharides (MOs) have unique health benefits for newborns, and MOs are important components in mammalian milk. The present study was conducted to provide a comprehensive analysis of MOs in important domestic animals, including goats, cows, camels and sheep. The comparison with human MOs was conducted simultaneously. Furthermore, analysis of the relative abundance of sheep MOs among different breeds (Hu sheep, East Friesen sheep, East Friesen-Hu crossbred sheep) and lactation periods (colostrum, mature milk) was performed. In general, 35, 24 19, 26, and 16 MOs were identified in human, goat, bovine, camel and sheep milk, respectively. The type of sheep MOs was not greatly influenced by the breeds and lactation period. Hu sheep colostrum had the highest abundance of MOs among six sheep milks, followed by East Friesen sheep colostrum, while East Friesen-Hu crossbred sheep mature milk had the lowest abundance of MOs. These findings provide evidence for the potential value of MOs from domestic animal milk for the commercial applications.

Fibroblast growth factor receptor 3 mutation attenuates response to immune checkpoint blockade in metastatic urothelial carcinoma by driving immunosuppressive microenvironment.

BACKGROUND: Immune checkpoint blockade (ICB) therapy holds promise in metastatic urothelial carcinoma (UC). Fibroblast growth factor receptor 3 (FGFR3) mutation drives T-cell-depleted microenvironment in UC, which led to the hypothesis that FGFR3 mutation might attenuate response to ICB in patients with metastatic UC. The study aims to compare prognosis and response between patients with FGFR3-mutated and FGFR3-wildtype metastatic UC after ICB therapy, and decode the potential molecular mechanisms. METHODS: Based on the single-arm, multicenter, phase 2 trial, IMvigor210, we conducted a propensity score matched (PSM) analysis. After a 1:1 ratio PSM method, 39 patients with FGFR3-mutated and 39 FGFR3-wildtype metastatic UC treated with atezolizumab were enrolled. A meta-analysis through systematical database retrieval was conducted for validation. In addition, we performed single-cell RNA sequencing on three FGFR3-mutated and three FGFR3-wildtype UC tumors and analyzed 58,069 single cells. RESULTS: The PSM analysis indicated FGFR3-mutated patients had worse overall survival (OS) in comparison to FGFR3-wildtype patients (HR=2.11, 95% CI=(1.16 to 3.85), p=0.015) receiving atezolizumab. The median OS was 9.2 months (FGFR3-mutated) versus 21.0 months (FGFR3-wildtype). FGFR3-mutated patients had lower disease control rate than FGFR3-wildtype patients (41.0% vs 66.7%, p=0.023). The meta-analysis involving 938 patients with metastatic UC confirmed FGFR3 mutation was associated with worse OS after ICB (HR=1.28, 95% CI=(1.04 to 1.59), p=0.02). Single-cell RNA transcriptome analysis identified FGFR3-mutated UC carried a stronger immunosuppressive microenvironment compared with FGFR3-wildtype UC. FGFR3-mutated UC exhibited less immune infiltration, and lower T-cell cytotoxicity. Higher TREM2+ macrophage abundance in FGFR3-mutated UC can undermine and suppress the T cells, potentially contributing to the formation of an immunosuppressive microenvironment. Lower inflammatory-cancer-associated fibroblasts in FGFR3-mutated UC recruited less chemokines in antitumor immunity but expressed growth factors to promote FGFR3-mutated malignant cell development. FGFR3-mutated UC carried abundance of malignant cells characterized by high hypoxia/metabolism and low interferon response phenotype. CONCLUSIONS: FGFR3 mutation can attenuate prognosis and response to ICB in patients with metastatic UC. FGFR3-mutated UC carries a stronger immunosuppressive microenvironment in comparison with FGFR3-wildtype UC. Inhibition of FGFR3 might activate the immune microenvironment, and the combination of FGFR inhibitor targeted therapy and ICB might be a promising therapeutic regimen in metastatic UC, providing important implications for UC clinical management.