Original Article |
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Corresponding author: Jayaseelan Vijayashree Priyadharsini ( viji26priya@gmail.com ) © 2025 Yathin Reddy Putta, Anitha Pandi, Jayaseelan Vijayashree Priyadharsini.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Putta YR, Pandi A, Priyadharsini JV (2025) Investigations on the dysregulated genes in high-fat-fed mice infected with Prevotella intermedia and their possible role in the development of hepatocellular carcinoma. Folia Medica 67(2): e143604. https://doi.org/10.3897/folmed.67.e143604
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Introduction: Hepatocellular carcinoma (HCC) is a leading global cancer, often linked to various factors, including viral infections and metabolic disorders. Recent studies suggest that microbial infections, particularly from oral pathogens like Prevotella intermedia (Pi), may elevate the progression of HCC through dysbiosis and chronic inflammation.
Aim: In view of this, the study aimed to identify candidate genes in high-fat diet-fed mice infected with Pi and to assess the relevance of these orthologous genes in the development of human HCC.
Materials and methods: The GEO dataset, GSE136937, was employed to identify the differentially expressed genes across two datasets viz., regular chow-fed and high-fat diet-fed mice infected with Pi. A comparison was made between normal vs. high-fat diet-fed mice infected with Pi to demonstrate the influence of the microbial factor on the development of metabolic disorders and cancer. The identified DEGs were subjected to protein-protein interaction (PPI) analysis and gene ontology (GO) assessments. Human orthologs were evaluated for gene expression status and survival using the TCGA dataset.
Results: The analysis revealed numerous DEGs between infected and uninfected groups. The top 20 DEGs (16 upregulated, 4 downregulated) were further investigated in liver hepatocellular carcinoma patients (TCGA). Notably, genes RMND1 and CYP3A43 displayed similar expression patterns in both mouse and human datasets. High RMND1 expression was associated with poor prognosis, while low CYP3A43 expression indicated a poor survival outcome in HCC patients.
Conclusion: Metabolic disorders in conjunction with microbial dysbiosis together could support the malignant phenotype by modifying the expression profiles of key genes involved in carcinogenesis. More intense experimental and in vivo studies are needed to further confirm the association of these candidate genes with HCC.
gene expression, inflammation, prognosis, survival
Hepatocellular carcinoma (HCC) is one of the most common forms of cancer and is reported to be the third leading cause of death globally. HCC constitutes around 80% of all liver cancers across the world. Hepatitis B and C viruses, non-alcoholic fatty liver disease (NAFLD), metabolic disorders, exposure to aflatoxins, environmental factors, and habits such as smoking and alcoholism contribute immensely to the development of HCC.[
The human microbiome comprises all microbes and their genes in the human body. Among all other regions, the gut and oral microbiota play a vital role in metabolism and immune function. Derangements in this microbiome have been associated with chronic liver disease, carcinoma of the head and neck region[
The study has been designed to identify the differentially expressed genes (DEGs) in high-fat, diet-fed mice treated with Pi compared to uninfected, normal, diet-fed mice. The results would provide insight into those genes exclusively expressed in mice with metabolic disorder infected with the oral-dental pathogen, Pi. Here, the crosstalk between the genes involved in metabolic disruption and microbial dysbiosis will be analyzed. The DEGs identified were further investigated to demonstrate their expression profiles in liver hepatocellular carcinoma patients (LIHC) to bring in a possible association between the genes expressed in the presence of the microbial pathogen and their human orthologs in connection with the disease.
The GEOmnibus dataset GSE136937, consisting of mouse model C57BL/6N/Jcl, was used for the study. The sample dataset taken for the present analysis consisted of 3 samples of regular chow-fed mice (GSM4062010, GSM4062011, GSM4062012), four samples from high-fat-fed mice exposed to Prevotella intermedia (GSM4062017, GSM4062018, GSM4062019, GSM4062020) and four samples from untreated high-fat-fed mice (GSM4062013, GSM4062014, GSM4062015, GSM4062016). Gene expression was compared between regular chow-fed mice and the high-fat-fed mice exposed to Prevotella intermedia[
A set of the top 20 DEGs (differentially expressed genes) identified in the high-fat diet-fed mice exposed to Prevotella intermedia was evaluated for protein-protein interactions of these genes using the STRING (Search Tool for the Retrieval of Interacting Genes/Proteins), version 12. The interaction source included text mining, experiments, databases, co-expression, neighborhood, gene fusion, and co-occurrence sources, with a minimum score of 0.400. The PPI enrichment score evaluates the query protein’s observed interactions against the entire proteome. A p-value less than 0.05 implies that the observed interactions are statistically significant. This bioinformatics platform provided data on direct physical interactions and functional associations of proteins. In the network, proteins are denoted as nodes, while the edges indicate the type of interaction, whether physical, enzymatic, or genetic.[
The PANTHER database (v16.0; Protein Analysis Through Evolutionary Relationships) was employed for the gene ontology analysis of the curated DEGs in Mus musculus. This analysis allowed us to understand the molecular pathways, functions, biological processes, and subcellular localization of gene products. A user-defined query of the top 20 genes was used to identify the pathways in which the genes are clustered. Additionally, we performed pathway-based classification to identify and explore potential pathways associated with the genes, contributing to a more comprehensive analysis.[
Understanding large-scale studies involves identifying crucial biological pathways and protein complexes within intricate datasets. Metascape is a user-friendly web portal that helps experimental biologists analyze and interpret this data type by integrating diverse biological databases and analytical tools. It simplifies the process and provides precise results with features like functional enrichment, interactome analysis, and gene annotation, making it easier for researchers to compare data from different experiments. The present study utilized DisGENET analysis to integrate various data types. The DEGs identified were submitted as a query and checked with the Homo sapiens. This process was conducted to analyze the functional role of orthologous genes.[
The study analyzed the top 20 DEGs in high-fat-fed mice exposed to Prevotella intermedia in the hepatocellular carcinoma dataset using the UALCAN database (http://ualcan.path.uab.edu/cgi-bin/TCGA-survival). The study involved 371 samples from patients with liver hepatocellular primary tumors and 50 paired normal samples. The expression profile was measured in transcripts per million (TPM), a standard unit for normalizing RNA-seq data. The significance between different groups was determined by creating Box-Whisker plots using the TPM values. Additionally, the study demonstrated the overall survival of patients with liver hepatocellular carcinoma (LHCC) using Kaplan-Meier analysis. By comparing the high-expression and low/medium-expression groups, the study illustrated the effect of gene expression changes on patients’ overall survival.[
The gene expression data from multiple datasets were rigorously analyzed using the powerful GEO2R tool, which effectively leverages R packages from Limma to meticulously examine the microarray data and present results in comprehensive tables and graphic plots.[
The comparison between high-fat treated mice infected with Pi and high-fat-fed mice returned no significant hub of differentially expressed genes (Fig.
(a) Volcano plot demonstrating differentially expressed genes (DEGs) in the liver of high-fat diet-fed C57BL/6 mice treated with Prevotella intermedia vs high-fat diet-fed C57BL/6 mice; (b) Volcano plot demonstrating differentially expressed genes (DEGs) in the liver of high-fat diet-fed C57BL/6 mice treated with Prevotella intermedia vs Untreated C57BL/6 mice. Blue dots indicate genes that are downregulated, and red dots represent genes that are upregulated. A p-value less than 0.05 was considered significant.
List of top 20 genes differentially expressed in the liver of high-fat diet-fed C57BL/6 mice treated with Prevotella intermedia compared to regular chow-fed mice. An adjusted p-value of less than 0.05 was considered to be significant
| Gene | Protein encoded | Adjusted p value | Log Fold Change | Gene expression |
| GM36283 | Predicted gene, 36283 | 0.00436 | 3.77 | Upregulated |
| USP18 | Ubiquitin specific peptidase 18 | 0.00436 | 2.12 | Upregulated |
| SLC26A10 | Solute carrier family 26, member 10 | 0.00436 | 2.47 | Upregulated |
| SLC25A27 | Solute carrier family 25, member 27 | 0.00436 | 2.13 | Upregulated |
| CYP3A11 | Cytochrome P450, family 3, subfamily a, polypeptide 11 | 0.00436 | −2.23 | Downregulated |
| AMDHD2 | Amidohydrolase domain containing 2 | 0.00436 | 2.38 | Upregulated |
| RMND1 | Required for meiotic nuclear division 1 homolog (S. cerevisiae) | 0.00436 | 1.98 | Upregulated |
| SCD1 | Stearoyl-Coenzyme A desaturase 1 | 0.00436 | −5.85 | Downregulated |
| MAT2A | Methionine adenosyltransferase II, alpha | 0.00436 | 1.84 | Upregulated |
| DACT1 | Dapper homolog 1, antagonist of beta-catenin (xenopus) | 0.00436 | 2.90 | Upregulated |
| ABHD2 | Abhydrolase domain containing 2 | 0.00436 | 3.37 | Upregulated |
| ZBP1 | Z-DNA binding protein 1 | 0.00436 | 2.25 | Upregulated |
| MBD4 | Methyl-CpG binding domain protein 4 | 0.00436 | 1.59 | Upregulated |
| CCND1 | Cyclin D1 | 0.00436 | 2.63 | Upregulated |
| CYP3A16 | Cytochrome P450, family 3, subfamily a, polypeptide 16 | 0.00436 | −2.04 | Downregulated |
| IRF7 | Interferon regulatory factor 7 | 0.00529 | 1.86 | Upregulated |
| CYP3A59 | Cytochrome P450, family 3, subfamily a, polypeptide 59 | 0.00529 | −1.83 | Downregulated |
| HAP1 | Huntingtin-associated protein 1 | 0.00673 | 1.46 | Upregulated |
| IFIT3B | Interferon-induced protein with tetratricopeptide repeats 3B | 0.00673 | 1.67 | Upregulated |
| CIART | Circadian associated repressor of transcription | 0.00707 | 3.61 | Upregulated |
Gene expression profile and survival analysis of DEGs identified in the high-fat diet-fed C57BL/6 mice treated with Prevotella intermedia in liver hepatocellular carcinoma patients. * Non-coding RNAs are excluded from the study
| Gene | Protein encoded | Gene expression in mouse liver cells | Gene expression in LIHC | P value | Survival (p value) | Survival outcome |
| GM36283 | Predicted gene, 36283 | Upregulated | Data unavailable | |||
| USP18 | Ubiquitin specific peptidase 18 | Upregulated | Insignificant | 2.86×10-01 | 0.027 | High expression, Poor prognosis |
| SLC26A10 | Solute carrier family 26, member 10 | Upregulated | Upregulated | 1.72×10-12 | 0.11 | Insignificant |
| SLC25A27 | Solute carrier family 25, member 27 | Upregulated | Upregulated | 7.46×10-09 | 0.24 | Insignificant |
| CYP3A11/CYP3A5 | Cytochrome P450, family 3, subfamily a, polypeptide 11 | Downregulated | Insignificant | 1.31×10-06 | 0.36 | Insignificant |
| AMDHD2 | Amidohydrolase domain containing 2 | Upregulated | Upregulated | 1.62×10-12 | 0.062 | Insignificant |
| RMND1 | Required for meiotic nuclear division 1 homolog (S. cerevisiae) | Upregulated | Upregulated | 1.55×10-11 | 0.024 | Poor prognosis |
| SCD1/SCD | Stearoyl-Coenzyme A desaturase 1 | Downregulated | Upregulated | 1.23×10-06 | 0.97 | Insignificant |
| MAT2A | Methionine adenosyltransferase II, alpha | Upregulated | Upregulated | 2.19×10-12 | 0.36 | Insignificant |
| DACT1 | Dapper homolog 1, antagonist of beta-catenin (xenopus) | Upregulated | Insignificant | 6.19×10-01 | 0.32 | Insignificant |
| ABHD2 | Abhydrolase domain containing 2 | Upregulated | Downregulated | 1.00×10-02 | 0.93 | Insignificant |
| ZBP1 | Z-DNA binding protein 1 | Upregulated | Upregulated | 3.09×10-01 | 0.54 | Insignificant |
| MBD4 | Methyl-CpG binding domain protein 4 | Upregulated | Upregulated | 1.99×10-11 | 0.8 | Insignificant |
| CCND1 | Cyclin D1 | Upregulated | Downregulated | 1.79×10-01 | 0.95 | Insignificant |
| CYP3A16/CYP3A5 | Cytochrome P450, family 3, subfamily a, polypeptide 16 | Downregulated | Insignificant | 7.94×10-01 | 0.0077 | Poor prognosis |
| IRF7 | Interferon regulatory factor 7 | Upregulated | Insignificant | 1.41×10-01 | 0.079 | Insignificant |
| CYP3A59/CYP3A43 | Cytochrome P450, family 3, subfamily a, polypeptide 59 | Downregulated | Downregulated | 3.98×10-07 | 0.028 | Poor prognosis |
| HAP1 | Huntingtin-associated protein 1 | Upregulated | Insignificant | 1.00×10-01 | 0.6 | Insignificant |
| IFIT3B/IFIT3 | Interferon-induced protein with tetratricopeptide repeats 3B | Upregulated | Insignificant | 6.19×10-01 | 0.99 | Insignificant |
| CIART/C1ORF51 | Circadian associated repressor of transcription | Upregulated | Upregulated | 1.62×10-12 | 0.1 | Insignificant |
The protein-protein interaction network of 19 DEGs presented two clusters of proteins: Zbp1, Irf7, Usp18, Abhd2, Ifit3b, and Slc25a27, Cyp3a11, and Cyp3a16. The other proteins remained as independent entities. There were 19 nodes and 7 edges, with a PPI enrichment value of 0.000618 (Fig.
The gene enrichment analysis performed using Metascape on human orthologs of the mouse DEGs identified returned four significant pathways involved in (a) regulation of type 1 interferon-mediated signaling pathway, nuclear receptor meta pathway, DNA damage response pathway, and cellular catabolic pathway. The -log10 p value was highly significant for the interferon-mediated signaling pathway while moderately significant for the cellular catabolic process (Fig.
Among the top 20 curated genes, nine were found to be upregulated, three were downregulated, 7 produced insignificant expression, and data was unavailable for GM36283. The USP18 gene was upregulated in high-fat diet-fed mice, with a significant influence over survival in LIHC patient. However, this gene was excluded since the gene expression profile was insignificant between the normal and primary tumor groups of LIHC patients. Upon searching for similar expression profiles, the two genes, viz., RMND1 and CYP3A16, demonstrated identical gene expression in high-fat diet-fed mice treated with Pi. The RMND1 coding for the required meiotic nuclear division 1 homolog (S. cerevisiae) protein was overexpressed in both datasets (Fig.
(a) Bar graph showing increased expression of RMND1 gene in C57BL/6 mice treated with Prevotella intermedia (p=0.00436); (b) Box Whisker plot demonstrating the upregulation of RMND1 gene in LIHC patients. A statistically significant increase in the level of RMND1 was observed in the patients (p=1.55×10-11); (c) Kaplan Meier survival analysis demonstrating poor prognosis in LIHC patients presenting with increased expression of RMND1 gene (p=0.0015). A p-value of less than 0.05 was considered to be significant.
(a) Bar graph showing decreased expression of CYP3A59 gene in C57BL/6 mice treated with Prevotella intermedia (p=0.00529); (b) Box Whisker plot demonstrating the downregulation of CYP3A43 gene in LIHC patients. A statistically significant decrease in the level of CYP3A43 was observed in the patients (p=3.98×10-07); (c) Kaplan Meier survival analysis demonstrating poor prognosis in LIHC patients presenting with decreased expression of CYP3A59/CYP3A43 gene (p=0.00018). A p-value of less than 0.05 was considered to be significant.
The Kaplan-Meier survival plot predicted better survival outcomes in patients with low expression of RMND1. The hazard ratio (HR) was found to be 1.74 (95% CI-1.23 – 2.46), indicating that patients with increased expression of RMND1 were 1.74 times at risk of death compared to the low expression group (Fig.
Metabolic disorders are a group of conditions that are characterized by dysregulation in the metabolic pathways. Mounting evidence has shown that metabolic disorders increase the risk of developing cancer.[
The RMND1 gene, associated with mitochondrial function, has been implicated in cell proliferation and survival, which could explain its upregulation in HCC and its association with a poor prognosis. A study investigated breast cancer risk variants on chromosome 6q25, focusing on their associations with different breast cancer phenotypes and their regulation of critical genes, including ESR1, RMND1, and CCDC170. Using data from over 118,000 individuals, researchers identified five independent causal variants influencing estrogen receptor status, HER2 subtypes, mammographic density, and tumor grade. Functional analysis revealed that these variants modulate gene expression through enhancer and silencer elements, suggesting a complex regulatory landscape contributing to breast cancer susceptibility.[
The downregulation of CYP3A59/CYP3A43, genes involved in drug metabolism and xenobiotic detoxification, may indicate a compromised ability to detoxify carcinogenic compounds, thereby facilitating carcinogenesis in the liver. Our findings align with previous research that has demonstrated the influence of periodontal pathogens on systemic inflammation and cancer progression.[
A study highlighted the essential role of mouse CYP enzymes and their human orthologs in metabolizing both endogenous and exogenous compounds. It highlights the impact of CYP enzyme activity on metabolic and toxicological processes, which aligns with our observations in liver cancer progression.[
While our study provides important insights into the potential role of CYP3A59/CYP3A43 and other genes in the progression of hepatocellular carcinoma in the context of Pi infection, it is crucial to acknowledge that these findings are based on in-silico analysis, which could be a major limitation of the study. However, the preliminary results obtained from our study can serve as the initiation point for conducting further research involving clinical studies on microbial dysbiosis as a key component of tumorigenesis in patients with severe metabolic disorders. Other limitations of the study were (a) the microbial exposure factors of the patients of the study is not well established, (b) epigenetic and epitranscriptomic factors also play a key role in the modulation of gene expression, hence it is noteworthy to investigate these mechanisms to acquire a more vivid picture on the molecular mechanisms, (c) dietary habits and underlying co-morbid conditions can affect the microbial load, thereby elevating or diminishing the risk of malignant transformations, therefore it is vital to accurately identify the microbial pathogens and quantify them to derive strong association with the cancer type. Until such studies are conducted, the connections drawn from our research remain hypothetical and should be viewed as a foundation for future exploration rather than definitive conclusions.
This study explored the potential link between metabolic disorders, Pi infection, and hepatocellular carcinoma progression by identifying differentially expressed genes, particularly CYP3A59/CYP3A43 and RMND1. Our findings suggest that these genes could play a significant role in the pathogenesis of HCC, possibly through their involvement in metabolic and inflammatory pathways. However, as this research is based on in-silico analysis, further clinical investigations are necessary to confirm these associations and fully understand the biological mechanisms at play. This study serves as a preliminary step towards uncovering the complex interactions between oral pathogens and liver cancer, highlighting the need for more comprehensive studies to establish Prevotella intermedia’s role in HCC and explore potential therapeutic targets.
The authors declare that there is no conflict of interest in this study.
None
The authors are grateful to all the consorts and groups involved in the compilation of data from patients for public use. Our sincere thanks also go to all the patients who have indirectly contributed to the scientific community by providing consent for sharing their data for research use.