Distinct photochemistry of adsorbed and coprecipitated dicarboxylates with ferrihydrite: Implications for iron reductive dissolution and carbon stabilization.

Although ligand-promoted photodissolution of ferrihydrite (FH) has long been known for low molecular weight organic acids (LMWOAs), such as oxalate (Oxa) and malonate (Mal), photochemistry of coprecipitated FH with Oxa and Mal remains unknown, despite the importance of these mineral-organic associations in carbon retention has been acknowledged recently. In this study, ferrihydrite-LMWOAs associations (FLAs) were synthesized under circumneutral conditions. Photo-dissolution kinetics of FLAs were compared with those of adsorbed LMWOAs on FH surface and dissolved Fe-LMWOAs complexes through monitoring Fe(II) formation and organic carbon decay. For aqueous Fe(III)-LMWOAs complexes, Fe(II) yield was controlled by the initial concentration of LMWOAs and nature of photochemically generated carbon-centered radicals. Inner-sphere mononuclear bidentate (MB) configuration dominated while LMWOAs were adsorbed on the FH surface. MB complex of FH-Oxa was more photoreactive, leading to the rapid depletion of Oxa. Oxa can be readsorbed but in the form of binuclear bidentate and outer-sphere complexation, with much lower photoreactivity. While LMWOAs was coprecipitated with FH, the combination mode of LMWOAs with FH includes surface adsorption with a mononuclear bidentate structure and internal physical inclusion. Higher content of LMWOAs in the FLAs promoted the photo-production of Fe(II) as compared to pure FH, while it was not the case for FLAs containing moderate amounts of LMWOAs. The distinct photochemistry of adsorbed and coprecipitated Fe-LMWOAs complexes is attributed to ligand availability and configuration patterns of LMWOAs on the surface or entrapped in the interior structure. The present findings have significant implications for understanding the photochemical redox cycling of iron across the interface of Fe-organic mineral associates.

Hypoxia-mediated attenuation of EGLN2 inhibition of the NF-κB signaling pathway leads to the formation of a loop between HIF-1α and MUC1-C promoting chemoresistance in bladder cancer.

The expression pattern of MUC1-C in tumors is closely linked to tumor progression; however, its specific mechanism remains unclear. The expression of MUC1-C in cancer and adjacent normal tissues was detected using immunohistochemistry and Western blot. The IC50 of cells to gemcitabine was determined using the CCK8 assay. The effects of hypoxia and MUC1-C on the behavioral and metabolic characteristics of bladder cancer cells were investigated. Gene expression was assessed through Western blot and polymerase chain reaction. The relationship between the genes was analyzed by co-immunoprecipitation, immunofluorescence and Western blot. Finally, the role of the EGLN2 and NF-κB signaling pathways in the interaction between MUC1-C and hypoxia-inducible factor-1α (HIF-1α) was investigated. MUC1-C expression is significantly higher in bladder cancer tissues than in adjacent normal tissues, particularly in large-volume tumors, and is closely correlated with clinical features such as tumor grade. Tumor volume-mediated hypoxia resulted in increased expression of MUC1-C and HIF-1α in bladder cancer cells. Under stimulation of hypoxia, the inhibitory effect of EGLN2 on the NF-κB signaling pathway was weakened, allowing NF-κB to promote the positive feedback formation of MUC1-C and HIF-1α. Simultaneously, EGLN2-mediated degradation of HIF-1α was reduced. This ultimately led to elevated HIF-1α-mediated downstream gene expression, promoting increased glucose uptake and glycolysis, and ultimately resulting in heightened chemotherapy resistance and malignancy.

Effects of depth of straw returning on maize yield potential and greenhouse gas emissions.

Appropriate straw incorporation has ample agronomic and environmental benefits, but most studies are limited to straw mulching or application on the soil surface. To determine the effect of depth of straw incorporation on the crop yield, soil organic carbon (SOC), total nitrogen (TN) and greenhouse gas emission, a total of 4 treatments were set up in this study, which comprised no straw returning (CK), straw returning at 15 cm (S15), straw returning at 25 cm (S25) and straw returning at 40 cm (S40). The results showed that straw incorporation significantly increased SOC, TN and C:N ratio. Compared with CK treatments, substantial increases in the grain yield (by 4.17~5.49% for S15 and 6.64~10.06% for S25) were observed under S15 and S25 treatments. S15 and S25 could significantly improve the carbon and nitrogen status of the 0-40 cm soil layer, thereby increased maize yield. The results showed that the maize yield was closely related to the soil carbon and nitrogen index of the 0-40 cm soil layer. In order to further evaluate the environmental benefits of straw returning, this study measured the global warming potential (GWP) and greenhouse gas emission intensity (GHGI). Compared with CK treatments, the GWP of S15, S25 and S40 treatments was increased by 9.35~20.37%, 4.27~7.67% and 0.72~6.14%, respectively, among which the S15 treatment contributed the most to the GWP of farmland. GHGI is an evaluation index of low-carbon agriculture at this stage, which takes into account both crop yield and global warming potential. In this study, GHGI showed a different trend from GWP. Compared with CK treatments, the S25 treatments had no significant difference in 2020, and decreased significantly in 2021 and 2022. This is due to the combined effect of maize yield and cumulative greenhouse gas emissions, indicating that the appropriate straw returning method can not only reduce the intensity of greenhouse gas emissions but also improve soil productivity and enhance the carbon sequestration effect of farmland soil, which is an ideal soil improvement and fertilization measure.

Effect of n-C-S-H on Hydration and Reinforcement of Mineral Powder-Cement System at Low Temperatures.

This paper investigated the effect of nano-calcium silicate hydrate (n-C-S-H) on the early compressive strength of mineral powder-cement systems under low-temperature curing conditions (5 °C). The hydration mechanism of n-C-S-H in the mineral powder-cement system at different dosages was analyzed by combining it with XRD, DSC-TG, MIP, and other techniques. The results show that n-C-S-H significantly enhances the early compressive strength of the mineral powder-cement system under low-temperature curing conditions, with optimal results observed at a dosage of 1.0% (mass fraction). The XRD, DSC-TG, and MIP tests reveal that n-C-S-H promotes the hydration of the mineral powder cement, accelerates the generation rate of hydration products, reduces the porosity of the hardened mineral powder-cement slurry, and improves the system's density.

Phosphate-mediated degradation of organic pollutants in water with peroxymonosulfate revisited: Radical or non-radical oxidation?

Whilst it is generally recognized that phosphate enables to promote the removal of some organic pollutants with peroxymonosulfate (PMS) oxidation, however, there is an ongoing debate as to whether free radicals are involved. By integrating different methodologies, here we provide new insights into the reaction mechanism of the binary mixture of phosphates (i.e., NaH2PO4, Na2HPO3, and NaH2PO2) with peroxymonosulfate (PMS) or hydrogen peroxide (H2O2). Enhanced degradation of organic pollutants and observation of 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) adducts (i.e. DMPOOH and 5,5-dimethyl-2-oxopyrroline-1-oxyl (DMPOX)) with electron paramagnetic resonance (EPR) in most phosphates/PMS system seemly support a radical-dominant mechanism. However, fluorescence probe experiments confirm that no significant amount of hydroxyl radicals (•OH) are produced in such reaction systems. PMS in the phosphate solutions (without any organics) remains relatively stable, but is only consumed while organic substrates are present, which is distinct from a typical radical-dominant Co2+/PMS system where PMS is continuously decomposed. Through density functional theory (DFT) calculation, the energy barriers of the phosphates/PMS reaction processes are greatly decreased when non-radical mechanism dominates. Complementary evidence suggests that the reactive intermediates of PMS-phosphate complex, rather than the free radicals, are capable of oxidizing electron-rich substrates such as DMPO and organic pollutants. Taking the case of phosphate/PMS system as an example, this study demonstrates the necessity of acquisition of lines of evidence for resolving paradoxes in identifying EPR adducts.

Multifaceted roles of PDCD6 both within and outside the cell.

Programmed cell death protein 6 (PDCD6) is an evolutionarily conserved Ca2+-binding protein. PDCD6 is involved in regulating multifaceted and pleiotropic cellular processes in different cellular compartments. For instance, nuclear PDCD6 regulates apoptosis and alternative splicing. PDCD6 is required for coat protein complex II-dependent endoplasmic reticulum-to-Golgi apparatus vesicular transport in the cytoplasm. Recent advances suggest that cytoplasmic PDCD6 is involved in the regulation of cytoskeletal dynamics and innate immune responses. Additionally, membranous PDCD6 participates in membrane repair through endosomal sorting complex required for transport complex-dependent membrane budding. Interestingly, extracellular vesicles are rich in PDCD6. Moreover, abnormal expression of PDCD6 is closely associated with many diseases, especially cancer. PDCD6 is therefore a multifaceted but pivotal protein in vivo. To gain a more comprehensive understanding of PDCD6 functions and to focus and stimulate PDCD6 research, this review summarizes key developments in its role in different subcellular compartments, processes, and pathologies.

HER2 Affects the Biological Behaviours of Bladder Cancer Cells and is Closely Associated with the Progression and Prognosis of Bladder Cancer.

OBJECTIVE: Given the growing recognition of molecular targets in oncology, this study aimed to examine the expression pattern and prognostic significance of human epidermal growth factor receptor-2 (HER2) in bladder cancer (BC) and the effects of HER2 knockdown on the biological behaviours of BC cells. METHODS: A total of 126 BC tissue samples and 20 samples of normal bladder mucosa were collected for immunohistochemical staining. The clinicopathological data were obtained from patients with BC. HER2 was knocked down in two BC cell lines (T24 and 5637) using lentiviral delivery of short hairpin RNA (shRNA), referred to as shHER2, with a blank control group (shCtrl) for comparison. A range of assays, including cell counting kit-8, colony formation, transwell, wound healing, and flow cytometry, were performed to assess the effects of HER2 knockdown on the proliferation, migration, cell cycle entry, and apoptosis of BC cells. RESULTS: The study revealed a notable overexpression rate of HER2 in BC tissues (57.1%) than in normal bladder mucosa (0%) (p < 0.001). HER2 overexpression was associated with tumour number (p < 0.0001), pathological grade (p < 0.0001), lymph node metastasis (p = 0.040), distant metastasis (p = 0.037), overall survival (p = 0.0006), and recurrence-free survival (RFS) (p < 0.0001). In contrast, no significant association was identified between HER2 overexpression and demographic factors such as sex (p = 0.687), age (p = 0.430), tumour size (p = 0.053), or T stage (p = 0.134). Furthermore, the experimental knockdown of HER2 in BC cells inhibited the proliferation and migration and promoted their apoptosis and cell cycle arrest in the G1 phase. CONCLUSIONS: The findings suggest HER2 as a potential therapeutic target for BC and underscore the promise of developing anti-HER2-targeting strategies for BC management.

HER2 Affects the Biological Behaviours of Bladder Cancer Cells and is Closely Associated with the Progression and Prognosis of Bladder Cancer

Objective: Given the growing recognition of molecular targets in oncology, this study aimed to examine the expression pattern and prognostic significance of human epidermal growth factor receptor-2 (HER2) in bladder cancer (BC) and the effects of HER2 knockdown on the biological behaviours of BC cells. Methods: A total of 126 BC tissue samples and 20 samples of normal bladder mucosa were collected for immunohistochemical staining. The clinicopathological data were obtained from patients with BC. HER2 was knocked down in two BC cell lines (T24 and 5637) using lentiviral delivery of short hairpin RNA (shRNA), referred to as shHER2, with a blank control group (shCtrl) for comparison. A range of assays, including cell counting kit-8, colony formation, transwell, wound healing, and flow cytometry, were performed to assess the effects of HER2 knockdown on the proliferation, migration, cell cycle entry, and apoptosis of BC cells. Results: The study revealed a notable overexpression rate of HER2 in BC tissues (57.1%) than in normal bladder mucosa (0%) (p < 0.001). HER2 overexpression was associated with tumour number (p < 0.0001), pathological grade (p < 0.0001), lymph node metastasis (p = 0.040), distant metastasis (p = 0.037), overall survival (p = 0.0006), and recurrence-free survival (RFS) (p < 0.0001). In contrast, no significant association was identified between HER2 overexpression and demographic factors such as sex (p = 0.687), age (p = 0.430), tumour size (p = 0.053), or T stage (p = 0.134). Furthermore, the experimental knockdown of HER2 in BC cells inhibited the proliferation and migration and promoted their apoptosis and cell cycle arrest in the G1 phase. Conclusions: The findings suggest HER2 as a potential therapeutic target for BC and underscore the promise of developing anti-HER2-targeting strategies for BC management (AU)

Device-assisted intravesical chemotherapy versus bacillus Calmette-Guerin for intermediate or high-risk non-muscle invasive bladder cancer: a systematic reviewer and meta-analysis.

PURPOSE: To investigate the effectiveness and safety of device-assisted intravesical chemotherapy compared to Bacillus Calmette-Guerin (BCG) in the treatment of patients with intermediate- and high-risk non-muscle-invasive bladder cancer (NMIBC). METHODS: In February 2023, a systematic search was conducted on the PubMed, Cochrane, and Embase databases. Following the PRISMA guidelines, a systematic review and meta-analysis of the primary outcomes of interest were performed. The review was prospectively registered on PROSPERO under the registration number CRD42023398559. RESULTS: A total of 10 studies involving 1160 patients were included. The results of the meta-analysis showed that compared to BCG, device-assisted chemotherapy had a lower recurrence rate (OR: 0.63, 95% CI: 0.48-0.84, p = 0.001), longer recurrence-free survival (OR: 0.64, 95% CI: 0.47-0.88, p = 0.006), and lower incidence of fever (OR: 0.18, 95% CI: 0.08-0.44, p = 0.0002). However, no significant differences were observed between the two groups in terms of progression, overall survival, progression-free survival, disease-free survival, overall adverse events, serious adverse events, hematuria, allergy, and general discomfort. Subgroup analysis revealed that neither chemohyperthermia (CHT) nor electromotive drug administration (EMDA) showed statistically significant differences in oncological outcomes compared to BCG. Regarding adverse events, both CHT and EMDA groups showed lower rates of fever compared to the BCG group (OR: 0.26, 95% CI: 0.10-0.67, p = 0.005, and OR: 0.14, 95% CI: 0.05-0.37, p < 0.0001, respectively). No significant differences were observed in the remaining adverse events between either the CHT or EMDA group and the BCG group. CONCLUSION: Device-assisted intravesical chemotherapy appears to be a safe and viable alternative to BCG for patients with intermediate and high-risk NMIBC, showing comparable oncological outcomes and adverse events.

Formation and function of multiciliated cells.

In vertebrates, multiciliated cells (MCCs) are terminally differentiated cells that line the airway tracts, brain ventricles, and reproductive ducts. Each MCC contains dozens to hundreds of motile cilia that beat in a synchronized manner to drive fluid flow across epithelia, the dysfunction of which is associated with a group of human diseases referred to as motile ciliopathies, such as primary cilia dyskinesia. Given the dynamic and complex process of multiciliogenesis, the biological events essential for forming multiple motile cilia are comparatively unelucidated. Thanks to advancements in genetic tools, omics technologies, and structural biology, significant progress has been achieved in the past decade in understanding the molecular mechanism underlying the regulation of multiple motile cilia formation. In this review, we discuss recent studies with ex vivo culture MCC and animal models, summarize current knowledge of multiciliogenesis, and particularly highlight recent advances and their implications.

The emerging roles of protein arginine methyltransferases in antiviral innate immune signaling pathways.

The Protein Arginine Methyltransferases (PRMTs) family is involved in various biological processes, including gene transcription, pre-mRNA splicing, mRNA translation, and protein stability. Recently, mounting evidence has shown that PRMTs also play critical roles in regulating the host antiviral immune response, either in an enzymatic activity dependent or independent manner. This review aims to provide an overview of the recent findings regarding the function and regulatory mechanisms of PRMTs in the antiviral response. These findings have the potential to aid in the discovery and design of novel therapeutic strategies for viral infections.

Glial Cells of the Central Nervous System: A Potential Target in Chronic Prostatitis/Chronic Pelvic Pain Syndrome.

Chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS) is one of the most common diseases of the male urological system while the etiology and treatment of CP/CPPS remain a thorny issue. Cumulative research suggested a potentially important role of glial cells in CP/CPPS. This narrative review retrospected literature and grasped the research process about glial cells and CP/CPPS. Three types of glial cells showed a crucial connection with general pain and psychosocial symptoms. Microglia might also be involved in lower urinary tract symptoms. Only microglia and astrocytes have been studied in the animal model of CP/CPPS. Activated microglia and reactive astrocytes were found to be involved in both pain and psychosocial symptoms of CP/CPPS. The possible mechanism might be to mediate the production of some inflammatory mediators and their interaction with neurons. Glial cells provide a new insight to understand the cause of complex symptoms of CP/CPPS and might become a novel target to develop new treatment options. However, the activation and action mechanism of glial cells in CP/CPPS needs to be further explored.

Outcomes of arteriovenous graft vs. fistula for haemodialysis access in the elderly: A systematic review and meta­analysis.

The impact of the type of vascular access on the outcomes in the elderly haemodialysis patients is still unclear. The goal of the present study was to compare survival outcomes in elderly haemodialysis patients who received either arteriovenous graft (AVG) or arteriovenous fistula (AVF). A systematic literature search was performed in EMBASE, Cochrane, MEDLINE, ScienceDirect and Google Scholar databases for papers published from January 1954 until January 2022. Risk of bias in the selected publications was assessed by Newcastle Ottawa scale or Cochrane risk of bias tool depending on the study design. Meta-analysis was carried out using the random-effects model. Data were reported as pooled odds ratio (OR) or hazard ratio (HR) with 95% confidence interval (CI). A total of 12 studies were included in the analysis. The majority of the studies had poor quality. Elderly patients receiving AVG had significantly worse survival rate compared with patients that received AVF for the haemodialysis access, with a pooled HR of 1.38 (95% CI, 1.24-1.53; I2=79.9%). Pooled HR for access survival was 1.60 (95% CI, 1.54-1.66; I2=0%). Pooled OR for primary patency rate, maturation failure and infections were 1.81 (95% CI, 0.73-4.49; I2=79.2%), 0.33 (95% CI, 0.12-0.91; I2=70.4%) and 9.74 (95% CI, 2.60-36.49; I2=52.4%), respectively. These results suggested that in elderly patients undergoing haemodialysis, AVG was associated with reduced overall survival and access survival, and higher infection rate, compared with AVF. Notably, AVG was also associated with a lower risk of maturation failure, presenting a potential advantage in specific patient populations (study registration: PROSPERO, no. CRD42022313199).

Extraperitoneal Versus Intraperitoneal Radical Cystectomy for Bladder Cancer: A Systematic Review and Meta-Analysis.

BACKGROUND: This study aimed to compare perioperative and oncologic outcomes of extraperitoneal radical cystectomy (EPRC) and transperitoneal radical cystectomy (TPRC). METHODS: A systematical search of multiple scientific databases was performed in September 2022. The systematic review and cumulative meta-analysis of the primary outcomes of interest were performed according to the PRISMA and AMSTAR guidelines and registered in the PROSPERO database (PROSPERO [CRD42022359322]). RESULTS: The review and analysis included eight studies with 989 participants. No significant differences were found between EPRC and TPRC in terms of operation time, estimated blood loss (EBL), hospital length of stay (LOS), or transfusion. A shorter exhaust time (standardized mean difference [SMD] - 0.59; 95 % confidence interval [CI] - 0.97 to 0.21; p = 0.002) and time to liquid intake (SMD, - 0.56; 95 % CI - 1.07 to 0.04; p = 0.03) were associated with EPRC. No clinically meaningful difference was observed in terms of postoperative infection, wound complications, postoperative genitourinary complications, late postoperative complications, early major complications, or late major complications. However, EPRC was related to lower incidences of early postoperative complications (odds ratio [OR], 0.66; 95 % CI 0.51-0.86; p = 0.002), gastrointestinal complications (OR 0.28; 95 % CI 0 0.17-0.46; p < 0.00001), and postoperative ileus (OR 0.38; 95 % CI 0.25-0.59; p < 0.0001). A higher incidence of postoperative lymphocele was associated with EPRC (OR 3.05; 95 % CI 1.13-8.25; p = 0.03). No clinically meaningful difference was found in terms of positive surgical margin (PSM), local recurrence, distant metastasis, or OS. CONCLUSIONS: Although EPRC had a higher incidence of lymphoceles than TPRC, it was found to have similar oncologic outcomes and fewer early complications, particularly in terms of postoperative gastrointestinal complications and ileus. These results suggest that EPRC is a safe option both functionally and oncologically.

Berberine Affects the Proliferation, Migration, Invasion, Cell Cycle, and Apoptosis of Bladder Cancer Cells T24 and 5637 by Down-Regulating the HER2/PI3K/AKT Signaling Pathway.

OBJECTIVE: To assess the anticancer effect, target, and mechanism of berberine on bladder cancer. METHODS: Bladder cancer T24 and 5637 cells were treated with different concentrations of berberine. Then, cell proliferation was assessed by cell counting kit-8 (CCK8) measure, cell migration and invasion were assessed by transwell method, cell cycle and apoptosis were assessed by flow cytometry, and the expression of human epidermal growth factor receptor-2/PhosphoInositide-3 Kinase/AKT Serine/Threonine Kinase (HER2/PI3K/AKT) proteins were assessed by Western blot. Berberine molecular docking and HER2 target were performed using the AutoDock Tools 1.5.6. Finally, HER2 inhibitors CP-724714 and berberine were used independently or in combination to detect AKT and P-AKT protein downstream changes by Western blot. RESULTS: Berberine inhibited the proliferation of T24 and 5637 bladder cancer cells in a concentration-dependent and time-dependent manner. Berberine can significantly inhibit the migration, invasion, and cell cycle progression of T24 and 5637 bladder cancer cells, promote their apoptosis, and down-regulate the expression of HER2/PI3K/AKT proteins. Berberine showed good docking with HER2 molecular target and had a similar and synergistic effect with HER2 inhibitor in T24 and 5637 bladder cancer cells. CONCLUSIONS: Berberine inhibited the proliferation, migration, invasion, and cell cycle progression of T24 and 5637 bladder cancer cells and promoted their apoptosis by down-regulating HER2/PI3K/AKT signaling pathway.

Berberine Affects the Proliferation, Migration, Invasion, Cell Cycle, and Apoptosis of Bladder Cancer Cells T24 and 5637 by Down-Regulating the HER2/PI3K/AKT Signaling Pathway

Objective: To assess the anticancer effect, target, and mechanism of berberine on bladder cancer. Methods: Bladder cancer T24 and 5637 cells were treated with different concentrations of berberine. Then, cell proliferation was assessed by cell counting kit-8 (CCK8) measure, cell migration and invasion were assessed by transwell method, cell cycle and apoptosis were assessed by flow cytometry, and the expression of human epidermal growth factor receptor-2/PhosphoInositide-3 Kinase/AKT Serine/Threonine Kinase (HER2/PI3K/AKT) proteins were assessed by Western blot. Berberine molecular docking and HER2 target were performed using the AutoDock Tools 1.5.6. Finally, HER2 inhibitors CP-724714 and berberine were used independently or in combination to detect AKT and P-AKT protein downstream changes by Western blot. Results: Berberine inhibited the proliferation of T24 and 5637 bladder cancer cells in a concentration-dependent and time-dependent manner. Berberine can significantly inhibit the migration, invasion, and cell cycle progression of T24 and 5637 bladder cancer cells, promote their apoptosis, and down-regulate the expression of HER2/PI3K/AKT proteins. Berberine showed good docking with HER2 molecular target and had a similar and synergistic effect with HER2 inhibitor in T24 and 5637 bladder cancer cells. Conclusions: Berberine inhibited the proliferation, migration, invasion, and cell cycle progression of T24 and 5637 bladder cancer cells and promoted their apoptosis by down-regulating HER2/PI3K/AKT signaling pathway (AU)

Poly-ADP-ribose polymerase (PARP) inhibitors and ovarian function.

Poly-ADP-ribose polymerase (PARP) plays an important role in DNA damage detection and repair. PARP inhibitors (PARPi) are a novel class of targeted agents used widely in the treatment of female cancer patients with BRCA mutations, including younger patients. However, the impact of PARPi on ovarian function remains a considerable problem in clinical practice. In this review article, we summarize the current understanding of PARPi's effects on the function of ovary and discuss their potential underlying mechanisms, highlighting the significance of further investigation on the criterion for ovarian failure and its preventive approaches during PARPi treatment.

Iron redox cycling in layered clay minerals and its impact on contaminant dynamics: A review.

A majority of clay minerals contain Fe, and the redox cycling of Fe(III)/Fe(II) in clay minerals has been extensively studied as it may fuel the biogeochemical cycles of nutrients and govern the mobility, toxicity and bioavailability of a number of environmental contaminants. There are three types of Fe in clay minerals, including structural Fe sandwiched in the lattice of clays, Fe species in interlayer space and adsorbed on the external surface of clays. They exhibit distinct reactivity towards contaminants due to their differences in redox properties and accessibility to contaminant species. In natural environments, microbially driven Fe(III)/Fe(II) redox cycling in clay minerals is thought to be important, whereas reductants (e.g., dithionite and Fe(II)) or oxidants (e.g., peroxygens) are capable of enhancing the rates and extents of redox dynamics in engineered systems. Fe(III)-containing clay minerals can directly react with oxidizable pollutants (e.g., phenols and polycyclic aromatic hydrocarbons (PAHs)), whereas structural Fe(II) is able to react with reducible pollutants, such as nitrate, nitroaromatic compounds, chlorinated aliphatic compounds. Also structural Fe(II) can transfer electrons to oxygen (O2), peroxymonosulfate (PMS), or hydrogen peroxide (H2O2), yielding reactive radicals that can promote the oxidative transformation of contaminants. This review summarizes the recent discoveries on redox reactivity of Fe in clay minerals and its links to fates of environmental contaminants. The biological and chemical reduction mechanisms of Fe(III)-clay minerals, as well as the interaction mechanism between Fe(III) or Fe(II)-containing clay minerals and contaminants are elaborated. Some knowledge gaps are identified for better understanding and modelling of clay-associated contaminant behavior and effective design of remediation solutions.