Viral integration promotes SV40T-induced immortalization by disturbing the expression of DNA/chromosome- and ECM-associated functional genes.

Lentivirus containing simian virus 40 large T antigen (SV40T) is routinely used to induce cell immortalization. However, the roles of viral integration itself in this progress is still controversial. Here, we transformed primary mouse embryonic fibroblasts (MEFs) with SV40T lentivirus and studied the roles of viral integration in the immortalization using RNA sequencing (RNA-seq) and whole genome sequencing (WGS). During the immortalization, differentially expressed genes (DGEs) are enriched in viral infection and several diverse activities. However, DEGs between immortalized and aging cells are significantly enriched in DNA/chromosome- and extracellular matrix (ECM)-associated activities. Gene regulatory network (GRN) analysis shows that although p53 is a key regulatory factor, many other transcription factors also play critical roles in the process, like STAT1. Of these DEGs, 32 genes have viral integration in their coding and/or regulatory regions. Our findings suggest that viral integration may promote SV40T-mediated immortalization by disturbing the expression of DNA/chromosome- and ECM-associated genes.

Haplotype-resolved assemblies and variant benchmark of a Chinese Quartet.

BACKGROUND: Recent state-of-the-art sequencing technologies enable the investigation of challenging regions in the human genome and expand the scope of variant benchmarking datasets. Herein, we sequence a Chinese Quartet, comprising two monozygotic twin daughters and their biological parents, using four short and long sequencing platforms (Illumina, BGI, PacBio, and Oxford Nanopore Technology). RESULTS: The long reads from the monozygotic twin daughters are phased into paternal and maternal haplotypes using the parent-child genetic map and for each haplotype. We also use long reads to generate haplotype-resolved whole-genome assemblies with completeness and continuity exceeding that of GRCh38. Using this Quartet, we comprehensively catalogue the human variant landscape, generating a dataset of 3,962,453 SNVs, 886,648 indels (< 50 bp), 9726 large deletions (≥ 50 bp), 15,600 large insertions (≥ 50 bp), 40 inversions, 31 complex structural variants, and 68 de novo mutations which are shared between the monozygotic twin daughters. Variants underrepresented in previous benchmarks owing to their complexity-including those located at long repeat regions, complex structural variants, and de novo mutations-are systematically examined in this study. CONCLUSIONS: In summary, this study provides high-quality haplotype-resolved assemblies and a comprehensive set of benchmarking resources for two Chinese monozygotic twin samples which, relative to existing benchmarks, offers expanded genomic coverage and insight into complex variant categories.

ADENOSINE MONOPHOSPHATE-ACTIVATED PROTEIN KINASE PHOSPHORYLATION MEDIATED BY SIRTUIN 5 ALLEVIATES SEPTIC ACUTE KIDNEY INJURY.

ABSTRACT: Background : Our previous studies have shown that ameliorating mitochondrial damage in renal tubular epithelial cells (RTECs) can alleviate septic acute kidney injury (SAKI). It is reported that AMPK phosphorylation (p-AMPK) could ameliorate mitochondrial damage in renal tissue and Sirtuin 5 (SIRT5) overexpression significantly enhanced the level of p-AMPK in bovine preadipocytes. However, the role of SIRT5-mediated phosphorylation of AMPK in SAKI needs to be clarified. Methods : WT/SIRT5 gene knockout mouse model of cecal ligation and puncture-induced SAKI and a human kidney 2 cell model of LPS-induced SAKI were constructed. An AMPK chemical activator and SIRT5 overexpression plasmid were used. Indexes of mitochondrial structure and function, level of p-AMPK, and expression of SIRT5 protein in renal tissue and RTECs were measured. Results : After sepsis stimulation, the p-AMPK level was decreased, mitochondrial structure was disrupted, and ATP content was decreased. Notably, an AMPK activator alleviated SAKI. Sirtuin 5 gene knockout significantly aggravated SAKI, while SIRT5 overexpression alleviated mitochondrial dysfunction after LPS stimulation, as manifested by the increase of p-AMPK level, the alleviation of mitochondrial structure damage, the restoration of ATP content, the decrease of proapoptotic protein expression, as well as the reduction of reactive oxygen species generation. Conclusions : Upregulation of SIRT5 expression can attenuate mitochondrial dysfunction in RTECs and alleviate SAKI by enhancing the phosphorylation of AMPK.

Integrating cell interaction with transcription factors to obtain a robust gene panel for prognostic prediction and therapies in cholangiocarcinoma.

Objective: The efficacy of immunotherapy for cholangiocarcinoma (CCA) is blocked by a high degree of tumor heterogeneity. Cell communication contributes to heterogeneity in the tumor microenvironment. This study aimed to explore critical cell signaling and biomarkers induced via cell communication during immune exhaustion in CCA. Methods: We constructed empirical Bayes and Markov random field models eLBP to determine transcription factors, interacting genes, and associated signaling pathways involved in cell-cell communication using single-cell RNAseq data. We then analyzed the mechanism of immune exhaustion during CCA progression. Results: We found that VEGFA-positive macrophages with high levels of LGALS9 could interact with HAVCR2 to promote the exhaustion of CD8+ T cells in CCA. Transcription factors SPI1 and IRF1 can upregulate the expression of LGALS9 in VEGFA-positive macrophages. Subsequently, we obtained a panel containing 54 genes through the model, which identified subtype S2 with high expression of immune checkpoint genes that are suitable for immunotherapy. Moreover, we found that patients with subtype S2 with a higher mutation ratio of MUC16 had immune-exhausted genes, such as HAVCR2 and TIGIT. Finally, we constructed a nine-gene eLBP-LASSO-COX risk model, which was designated the tumor microenvironment risk score (TMRS). Conclusion: Cell communication-related genes can be used as important markers for predicting patient prognosis and immunotherapy responses. The TMRS panel is a reliable tool for prognostic prediction and chemotherapeutic decision-making in CCA.

Melatonin suppresses ferroptosis via activation of the Nrf2/HO-1 signaling pathway in the mouse model of sepsis-induced acute kidney injury.

BACKGROUND: Ferroptosis is a regulated form of cell death. At present, the role of ferroptosis in sepsis-induced acute kidney injury (SAKI) has not been studied. Melatonin (MEL) has been reported to be an effective ferroptosis inhibitor, but it is unclear whether Melatonin can regulate ferroptosis in SAKI and whether its downstream mechanism correlates with the Nrf2/HO-1 pathway. METHODS: The cecal ligation and puncture (CLP) method and LPS injection were used to induce SAKI in mouse model. Ferroptosis markers, including malondialdehyde (MDA) and glutathione peroxidase 4 (GPX4), were assessed. The ferroptosis inhibitor ferrostatin-1 (Fer-1) was used to explore the role of ferroptosis in SAKI. The GPX4 inhibitor RSL3, the HO-1 inhibitor zinc protoporphyrin(ZnPP), and the Nrf2 inhibitor ML385 were used to explore the specific mechanism of MEL in alleviation of SAKI. RESULTS: The ferroptosis level was increased in the renal tissue of CLP- and LPS-induced septic mice. Both Fer-1 and MEL administration could suppress ferroptosis and attenuate kidney injury upon sepsis challenge. RSL3 partially blocked MEL's beneficial renal-protective effects. MEL up-regulated Nrf2 and HO-1 in CLP mice, and both ZnPP and ML385 blocked the MEL-mediated effects of ferroptosis inhibition and renal protection. CONCLUSIONS: Ferroptosis aggravates SAKI. Melatonin treatment suppresses ferroptosis and alleviates kidney injury in the context of experimental sepsis by upregulating Nrf2/HO-1 pathway.

D2 Plot, a Matrix of DNA Density and Distance to Periphery, Reveals Functional Genome Regions.

The execution of biological activities inside space-limited cell nuclei requires sophisticated organization. Current studies on the 3D genome focus on chromatin interactions and local structures, e.g., topologically associating domains (TADs). In this study, two global physical properties: DNA density and distance to nuclear periphery (DisTP), are introduced and a 2D matrix, D2 plot, is constructed for mapping genetic and epigenetic markers. Distinct patterns of functional markers on the D2 plot, indicating its ability to compartmentalize functional genome regions, are observed. Furthermore, enrichments of transcription-related markers are concatenated into a cross-species transcriptional activation model, where the nucleus is divided into four areas: active, intermediate, repress and histone, and repress and repeat. Based on the trajectories of the genomic regions on D2 plot, the constantly active and newly activated genes are successfully identified during olfactory sensory neuron maturation. The analysis reveals that the D2 plot effectively categorizes functional regions and provides a universal and transcription-related measurement for the 3D genome.

Cellular heterogeneity and transcriptomic profiles during intrahepatic cholangiocarcinoma initiation and progression.

BACKGROUND AND AIMS: Intrahepatic cholangiocarcinoma (ICC) is not fully investigated, and how stromal cells contribute to ICC formation is poorly understood. We aimed to uncover ICC origin, cellular heterogeneity, and critical modulators during ICC initiation/progression, and to decipher how fibroblast and endothelial cells in the stromal compartment favor ICC progression. APPROACH AND RESULTS: We performed single-cell RNA sequencing (scRNA-seq) using AKT/Notch intracellular domain-induced mouse ICC tissues at early, middle, and late stages. We analyzed the transcriptomic landscape, cellular classification and evolution, and intercellular communication during ICC initiation/progression. We confirmed the findings using quantitative real-time PCR, western blotting, immunohistochemistry or immunofluorescence, and gene knockout/knockdown analysis. We identified stress-responding and proliferating subpopulations in late-stage mouse ICC tissues and validated them using human scRNA-seq data sets. By integrating weighted correlation network analysis and protein-protein interaction through least absolute shrinkage and selection operator regression, we identified zinc finger, MIZ-type containing 1 (Zmiz1) and Y box protein 1 (Ybx1) as core transcription factors required by stress-responding and proliferating ICC cells, respectively. Knockout of either one led to the blockade of ICC initiation/progression. Using two other ICC mouse models (YAP/AKT, KRAS/p19) and human ICC scRNA-seq data sets, we confirmed the orchestrating roles of Zmiz1 and Ybx1 in ICC occurrence and development. In addition, hes family bHLH transcription factor 1, cofilin 1, and inhibitor of DNA binding 1 were identified as driver genes for ICC. Moreover, periportal liver sinusoidal endothelial cells could differentiate into tip endothelial cells to promote ICC development, and this was Dll4-Notch4-Efnb2 signaling-dependent. CONCLUSIONS: Stress-responding and ICC proliferating subtypes were identified, and Zmiz1 and Ybx1 were revealed as core transcription factors in these subtypes. Fibroblast-endothelial cell interaction promotes ICC development.

Integrating bulk and single-cell RNA sequencing reveals cellular heterogeneity and immune infiltration in hepatocellular carcinoma.

Efficacy of immunotherapy in hepatocellular carcinoma (HCC) is blocked by its high degree of inter- and intra-tumor heterogeneity and immunosuppressive tumor microenvironment. However, the correlation between tumor heterogeneity and immunosuppressive microenvironment in HCC has not been well addressed. Here, we endeavored to dissect inter- and intra-tumor heterogeneity in HCC and uncover how they contribute to the immunosuppressive microenvironment. We performed consensus molecular subtyping with non-negative matrix factorization (NMF) clustering to stratify the inter-heterogeneity profile of HCC tumors. We grouped HCC tumors from the Cancer Genome Atlas (TCGA) patients into three subtypes (S1, S2 and S3), where S1 was characterized as a 'hot tumor' profile with high expression level of T cell genes and rate of immune scores. S2 was characterized as a 'cold tumor' profile with the highest tumor purity score, and S3 as an 'immunosuppressed tumor' profile with the poorest prognosis and a high expression level of immunosuppressive genes such as cytotoxic T-lymphocyte-associated protein-4, TIGIT, and PDCD1. Moreover, we combined weighted gene co-expression network analysis and single-cell regulatory network inference and clustering (SCENIC) in the single-cell dataset of the S3-like subtype (CS3) and identified a transcription factor, BATF, which could upregulate immunosuppressive genes. Finally, we identified a cell interaction network in which a myeloid-derived suppressor cell-like macrophage subtype could promote the formation of immunosuppressive T-cells.

A novel model for extrapleural cavity metastasis assessment in patients with lung cancer.

Aim: To investigate the clinical value of tumor markers in extrapleural tumor metastasis assessment of newly diagnosed lung cancer patients. Materials & methods: This study retrospectively analyzed 306 patients diagnosed with lung cancer accompanied by tumor metastasis. Patients were grouped into extrapleural tumor metastasis and intrapleural tumor metastasis. Seven serum tumor markers were included for analysis. Results: The area under curves of receiver operating characteristic curve based on binning decision tree algorithm were above 0.8 in both training and validation sets. A scorecard with a score below 3 suggested extrapleural tumor metastasis in newly diagnosed lung cancer patients. Conclusion: The serum tumor marker-derived model is a convenient and fast approach for extrapleural cavity metastasis assessment, which may provide positive implications in newly diagnosed lung cancer patients.

Efficacy and safety of mycophenolate mofetil in the treatment for IgA nephropathy: a meta-analysis of randomized controlled trials.

AIM: IgA nephropathy is virtually known as the most common glomerulopathy to end-stage renal failure in the world. Mycophenolate mofetil is a selective immunosuppressant widely used in organ transplantation, yet its tolerance and effectiveness in IgAN is controversial. METHODS: This is a systematic review and random-effects meta-analysis, searching PubMed, Embase, Te Cochrane Library, Science Citation Index, Ovid evidence-based medicine, Chinese Biomedical Literature and Chinese Science and Technology Periodicals. Screen out randomized controlled trials on patients with biopsy-proven IgA nephropathy and analysis mycophenolate mofetil treatment regimens used for therapy of IgA nephropathy. Complete remission and partial remission, doubling of creatinine level, proteinuria, incidence of end-stage kidney disease, infection, Cushing syndrome, diabetes, hepatic dysfunction or gastrointestinal symptoms, neurologic or visual ambiguity, acne, and alopecia were observed. RESULTS: Nine relevant trials were conducted with 587 patients enrolled. In Mycophenolate mofetil or plus medium/low-dose steroid comparing full-dose steroid alone or placebo, there was no significant difference. The risk of Cushing syndrome and diabetes had been significantly lowered with Mycophenolate mofetil-treated patients, while the risk of infection had been increased. CONCLUSIONS: Mycophenolate mofetil therapy did not differ in reducing proteinuria and Scr in patients with IgAN who had persistent proteinuria, while having fewer Cushing syndrome and diabetes risk and more infection risk. However, larger randomized studies are needed to reveal these results.

A novel CD4+ CTL subtype characterized by chemotaxis and inflammation is involved in the pathogenesis of Graves' orbitopathy.

Graves' orbitopathy (GO), the most severe manifestation of Graves' hyperthyroidism (GH), is an autoimmune-mediated inflammatory disorder, and treatments often exhibit a low efficacy. CD4+ T cells have been reported to play vital roles in GO progression. To explore the pathogenic CD4+ T cell types that drive GO progression, we applied single-cell RNA sequencing (scRNA-Seq), T cell receptor sequencing (TCR-Seq), flow cytometry, immunofluorescence and mixed lymphocyte reaction (MLR) assays to evaluate CD4+ T cells from GO and GH patients. scRNA-Seq revealed the novel GO-specific cell type CD4+ cytotoxic T lymphocytes (CTLs), which are characterized by chemotactic and inflammatory features. The clonal expansion of this CD4+ CTL population, as demonstrated by TCR-Seq, along with their strong cytotoxic response to autoantigens, localization in orbital sites, and potential relationship with disease relapse provide strong evidence for the pathogenic roles of GZMB and IFN-γ-secreting CD4+ CTLs in GO. Therefore, cytotoxic pathways may become potential therapeutic targets for GO.

gCAnno: a graph-based single cell type annotation method.

BACKGROUND: Current single cell analysis methods annotate cell types at cluster-level rather than ideally at single cell level. Multiple exchangeable clustering methods and many tunable parameters have a substantial impact on the clustering outcome, often leading to incorrect cluster-level annotation or multiple runs of subsequent clustering steps. To address these limitations, methods based on well-annotated reference atlas has been proposed. However, these methods are currently not robust enough to handle datasets with different noise levels or from different platforms. RESULTS: Here, we present gCAnno, a graph-based Cell type Annotation method. First, gCAnno constructs cell type-gene bipartite graph and adopts graph embedding to obtain cell type specific genes. Then, naïve Bayes (gCAnno-Bayes) and SVM (gCAnno-SVM) classifiers are built for annotation. We compared the performance of gCAnno to other state-of-art methods on multiple single cell datasets, either with various noise levels or from different platforms. The results showed that gCAnno outperforms other state-of-art methods with higher accuracy and robustness. CONCLUSIONS: gCAnno is a robust and accurate cell type annotation tool for single cell RNA analysis. The source code of gCAnno is publicly available at https://github.com/xjtu-omics/gCAnno .

Development of a prediction model with serum tumor markers to assess tumor metastasis in lung cancer.

BACKGROUND: This study aimed to explore the possibility of serum tumor markers (TMs) combinations in assessing tumor metastasis in patients with lung cancer. METHODS: We performed a retrospective analysis of 541 patients diagnosed with lung cancer between January 2016 and December 2017 at the Pneumology Department of Dazhou Central Hospital. Serum carcinoembryonic antigen (CEA), carbohydrate antigen (CA)125, CA153, CA199, CA724, cytokeratin 19 fragment (CYFRA), and neuron-specific enolase (NSE) levels were quantified in each patient at the time of lung cancer diagnosis. Metastasis was confirmed by computed tomography, and/or positron emission tomography, and/or surgery or other necessary methods. Receiver operating characteristic (ROC) curves and calibration curves were used to evaluate the performance of the model. RESULTS: Of the 541 patients eligible for final analysis, 253 were detected with metastasis and 288 were detected without metastasis. Compared with those in nonmetastatic patients, the serum CEA, CA125, CA199, CA153, CYFRA, and NSE levels were notably higher in metastatic patients (P < .05). The ROC curve demonstrated that the CEA-CA125-CA199-CA153-CYFRA-NSE-CA724 combination based on the cut-off value had an optimal area under the curve and specificity in assessing tumor metastasis. The decision tree model is a convenient and valuable tool for guiding the appropriate application of our model to assess metastasis in lung cancer patients. CONCLUSIONS: Our study suggested that the nomogram of the regression model is valuable for assessing tumor metastasis in newly diagnosed lung cancer patients before traditional standard methods are used. These findings could aid in the evaluation of metastasis in the clinic.

The clinical value of carcinoembryonic antigen for tumor metastasis assessment in lung cancer.

BACKGROUND: Carcinoembryonic antigen (CEA) as a diagnostic or prognostic marker has been widely studied in patients with lung cancer. However, the relationship between serum CEA and tumor metastasis in lung cancer remains controversial. This study aimed to investigate the ability of serum CEA to assess tumor metastasis in lung cancer patients. METHODS: We performed a retrospective analysis of 238 patients diagnosed with lung cancer from January to December 2016 at pneumology department of Dazhou Central Hospital (Dazhou, China). Serum CEA levels were quantified in each patient at the time of diagnosis of lung cancer. Metastasis was confirmed by computed tomography (CT), and/or positron emission tomography (PET) and/or surgery or other necessary detecting methods. RESULTS: Of the 213 patients eligible for final analysis, 128 were diagnosed with metastasis and 85 were diagnosed without metastasis. Compared to non-metastatic patients, the serum CEA was markedly higher in patients with metastasis (p < 0.001), and the area under the curve (AUC) was 0.724 (95% CI [0.654-0.793]). Subsequent analyses regarding the number and location of tumor metastases showed that CEA also had clinical value for multiple metastases versus single metastasis (AUC = 0.780, 95% CI [0.699-0.862]) and distant metastasis versus non-distant metastasis (AUC = 0.815, 95% CI [0.733-0.897]). In addition, we found that tumor size, histology diagnosis, age and gender had no impact on the assessment performance of CEA. CONCLUSION: Our study suggested the serum CEA as a valuable marker for tumor metastases assessment in newly diagnosed lung cancer patients, which could have some implications in clinical application.

MEpurity: estimating tumor purity using DNA methylation data.

MOTIVATION: Tumor purity is a fundamental property of each cancer sample and affects downstream investigations. Current tumor purity estimation methods either require matched normal sample or report moderately high tumor purity even on normal samples. It is critical to develop a novel computational approach to estimate tumor purity with sufficient precision based on tumor-only sample. RESULTS: In this study, we developed MEpurity, a beta mixture model-based algorithm, to estimate the tumor purity based on tumor-only Illumina Infinium 450k methylation microarray data. We applied MEpurity to both The Cancer Genome Atlas (TCGA) cancer data and cancer cell line data, demonstrating that MEpurity reports low tumor purity on normal samples and comparable results on tumor samples with other state-of-art methods. AVAILABILITY AND IMPLEMENTATION: MEpurity is a C++ program which is available at https://github.com/xjtu-omics/MEpurity. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Electrically enhanced adsorption and green regeneration for fluoride removal using Ti(OH)4-loaded activated carbon electrodes.

An electrically enhanced fluoride removal method was developed that blended the merits of electrosorption and adsorbent adsorption. This method has the advantages of high adsorption selectivity and capacity for fluoride. The saturated adsorption capacity of Ti(OH)4 for fluoride in the electrode of Ti(OH)4-loaded activated carbon reached 115.2 mg/g when a voltage of +1.2 V was applied to the electrode. The electrode was easily and cleanly regenerated in a short time in aqueous solution with high fluoride concentrations when a voltage of -1.6 V was applied. The adsorption capacity of the Ti(OH)4-loaded electrode for fluoride did not decrease after multiple cycles of electrically enhanced adsorption and regeneration. Excellent adsorption selectivity for fluoride was achieved. The electrically enhanced adsorption method showed potential for fluoride removal.

Diffusion Performance of Fertilizer Nutrient through Polymer Latex Film.

Matching the nutrient release rate of coated fertilizer with the nutrient uptake rate of the crop is the best way to increase the utilization efficiency of nutrients and reduce environmental pollution from the fertilizer. The diffusion property and mechanism of nutrients through the film are the theoretical basis for the product pattern design of coated fertilizers. For the coated fertilizer with a single-component nutrient, an extended solution-diffusion model was used to describe the difference of nutrient release rate, and the release rate is proportional to the permeation coefficient and the solubility of the nutrient. For the double- and triple-component fertilizer of N-K, N-P, and N-P-K, because of the interaction among nutrient molecules and ions, the release rates of different nutrients were significantly affected by the components in the composite fertilizer. Coating the single-component fertilizer (i.e., nitrogen fertilizer, phosphate fertilizer, and potash fertilizer) first and subsequently bulk blending is expected to be a promising way to adjust flexibly the nutrient release rate to meet the nutrient uptake rate of the crop.

Performance of granular zirconium-iron oxide in the removal of fluoride from drinking water.

In this study, a granular zirconium-iron oxide (GZI) was successfully prepared using the extrusion method, and its defluoridation performance was systematically evaluated. The GZI was composed of amorphous and nano-scale oxide particles. The Zr and Fe were evenly distributed on its surface, with a Zr/Fe molar ratio of ∼2.3. The granular adsorbent was porous with high permeability potential. Moreover, it had excellent mechanical stability and high crushing strength, which ensured less material breakage and mass loss in practical use. In batch tests, the GZI showed a high adsorption capacity of 9.80 mg/g under an equilibrium concentration of 10 mg/L at pH 7.0, which outperformed many other reported granular adsorbents. The GZI performed well over a wide pH range, of 3.5-8.0, and especially well at pH 6.0-8.0, which was the preferred range for actual application. Fluoride adsorption on GZI followed pseudo-second-order kinetics and could be well described by the Freundlich equilibrium model. With the exception of HCO(3)(-), other co-existing anions and HA did not evidently inhibit fluoride removal by GZI when considering their real concentrations in natural groundwater, which showed that GZI had a high selectivity for fluoride. In column tests using real groundwater as influent, about 370, 239 and 128 bed volumes (BVs) of groundwater were treated before breakthrough was reached under space velocities (SVs) of 0.5, 1 and 3 h(-1), respectively. Additionally, the toxicity characteristic leaching procedure (TCLP) results suggested that the spent GZI was inert and could be safely disposed of in landfill. In conclusion, this granular adsorbent showed high potential for fluoride removal from real groundwater, due to its high performance and physical-chemical properties.

The adsorption and reaction of a titanate coupling reagent on the surfaces of different nanoparticles in supercritical CO2.

The adsorption and reaction in supercritical CO2 of the titanate coupling reagent NDZ-201 on the surfaces of seven metal oxide particles, SiO2, Al2O3, ZrO2, TiO2 (anatase), TiO2 (rutile), Fe2O3, and Fe3O4, was investigated. FTIR and TG analysis indicated that the adsorption and reaction were different on different particle surfaces. On SiO2 and Al2O3 particles, there was a chemical reaction of the titanate coupling reagent on the surfaces. On the surfaces of ZrO2 and TiO2 (anatase) particles, there were two kinds of adsorption, weak and strong adsorption. On the surfaces of TiO2 (rutile), Fe2O3, and Fe3O4 particles, there was only weak adsorption. The acidity or basicity of the OH groups on the particle surface was the key factor that determined if a surface reaction occurred. When the OH groups were acidic, the titanate coupling reagent reacted with these, but otherwise, there was no reaction. The surface density of OH groups on the original particles and the amount of titanate coupling reagent adsorbed and reacted were estimated from TG analysis. The reactivity of the surface OH groups of Al2O3 particles was higher than that of the SiO2 particles.