The present study aimed to investigate whether soluble protein hydrolysate (SPH) protects against intestinal oxidative stress injury. An lactate dehydrogenase assay was used to assess the cytotoxicity and protective effect of SPH. For assessment, friend virus B NIH Jackson mouse pups aged 21 days were administered with 5% w/v soluble protein hydrolysate (SPH) through drinking water for 14 days and then luminally injected with 0.3% or 0.6% HO. Thereafter, the fecal samples of mice were collected, and the mice were sacrificed. Intestinal epithelial injury was assessed, and the expressions of 84 oxidative stress‑related genes in intestinal tissues was determined. SPH prophylactically protected against HO‑induced oxidative stress injury in human intestinal epithelial cells. An animal model of oxidative stress‑induced intestinal injury was established using 0.3 and 0.6% HO. SPH treatment reduced oxidative stress (0.3% HO)‑induced gut injury in mice. As no accelerated body growth was observed in SPH‑treated mice, it was hypothesized that the underlying protective mechanism of SPH is not related to nutrient oversupply. Treatment with SPH upregulated five oxidative protective genes that were not consistent between the sexes. Some antioxidative genes, including ferritin heavy polypeptide‑1 (), heme oxygenase‑1 (), NAD(P)H dehydrogenase quinone 1 () and superoxide dismutase 1 (), were commonly upregulated in both male and female mice. Overall, an antioxidative protective effect was observed following SPH treatment, which may be attributed to the upregulation of genes that protect against oxidative damage. The findings of the present study highlight the promising potential of SPH as a functional food for alleviating intestinal oxidative stress injury.

Tumor tissues generally exist in a relatively hypovascular state, and cancer cells must adapt to severe tissue conditions with a limited molecular oxygen and nutrient supply for their survival. Lipid metabolism serves a role in this adaptation. Lipids are supplied not only through the bloodstream but also through autonomous synthesis by cancer cells, and they function as sources of adenosine triphosphate and cell components. Although cancer‑associated lipid metabolism has been widely reviewed, how this metabolism responds to the tumor environment with poor molecular oxygen and nutrient supply remains to be fully discussed. The main aim of the present review was to summarize the findings on this issue and to provide insights into how cancer cells adapt to better cope with metabolic stresses within tumors. It may be suggested that diverse types of lipid metabolism have a role in enabling cancer cells to adapt to both hypoxia and nutrient‑poor conditions. Gaining a deeper understanding of these molecular mechanisms may reveal novel possibilities of exploration for cancer treatment.

Following the publication of this paper, it was drawn to the Editor's attention by a concerned reader that certain of the immunohistochemical data shown in Fig. 1C on p. 5 were strikingly similar to data appearing in different form in another article written by different authors at different research institutes that had already been published in the journal Archives of Biochemistry and Biophysics prior to the submission of this paper to . In view of the fact that the abovementioned data had already apparently been published previously, the Editor of has decided that this paper should be retracted from the Journal. After having been in contact with the authors, they accepted the decision to retract the paper. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 24: 833, 2021; DOI: 10.3892/mmr.2021.12473].

Subarachnoid hemorrhage (SAH), a prevalent cerebrovascular condition associated with a high mortality rate, frequently results in neuronal apoptosis and an unfavorable prognosis. The adjunctive use of traditional Chinese medicine (TCM) with surgical interventions exerts a therapeutic impact on SAH, potentially by facilitating apoptosis. However, the mechanism by which TCM mediates apoptosis following SAH remains unclear. In the present study, C57BL/6J mice were subjected to the modified single‑clamp puncture method to produce an model of SAH. Treatment of these mice with notoginsenoside R1 (NGR1) prevented short‑term neurological deficits, reduced the expression levels of apoptosis‑associated proteins and mitigated brain edema. In addition, an model of SAH was established by treating HT22 mouse neuronal cells with oxyhemoglobin (OxyHb). Treatment of these cells with NGR1 resulted in attenuation of the OxyHb‑induced apoptosis. Furthermore, RNA sequencing analysis was used to examine NGR1 + OxyHb and OxyHb groups. Statistically significant changes in the expression levels of apoptosis‑associated genes in OxyHb‑stimulated HT22 cells upon administration of NGR1 were observed. The present study investigated the potential mechanism by which NGR1 mitigates neuronal apoptosis, presenting a novel therapeutic approach for treating SAH through the use of a single TCM component.

Intrauterine growth restriction (IUGR) is the second most common obstetric complication after preterm labor. Appropriate trophoblast differentiation and placental structure, growth and function are key for the maintenance of pregnancy and normal fetal growth, development and survival. Extravillous trophoblast cell proliferation, migration and invasion are regulated by molecules produced by the fetomaternal interface, including autocrine factors produced by the trophoblast, such as insulin‑like growth factor (IGF)‑1. The aim of the present study was to investigate expression patterns of IGF‑1Ea isoform in IUGR placenta compared with appropriate for gestational age (AGA) pregnancies. Placental frozen tissues were collected from 13 AGA and 15 IUGR third trimester pregnancies for detection of IGF‑1Ea mRNA expression using reverse transcription‑quantitative PCR. Formalin‑fixed paraffin‑embedded samples from 15 AGA and 47 IUGR pregnancies were analyzed immunohistochemically for the identification and localization of the IGF‑1Ea peptide and comparison of clinical and histopathological parameters. To the best of our knowledge, the present study is the first to show IGF‑1Ea expression in third trimester human placenta. The results indicated that similar IGF‑1Ea mRNA expression levels were present in placental specimens from both groups. Cytoplasmic IGF‑1Ea expression was localized in the perivillous syncytiotrophoblast, extravillous trophoblast and endothelium of the villous and decidual vessels in both groups. No significant difference in the scores and intensity of IGF‑1Ea expression in perivillous syncytiotrophoblasts were noted in the IUGR vs. AGA pregnancies. Most IUGR cases showed negative IGF‑1Ea expression in the extravillous trophoblast, whereas AGA pregnancies showed predominantly positive immunostaining. A sex‑specific expression pattern was noted in the extravillous trophoblast, with negative IGF‑1Ea expression in the placentas of female IUGR cases. Additionally, positive immunostaining for IGF‑1Ea peptide in fetal villous and maternal decidual vessels, was more frequently observed in the IUGR group compared with AGA. In conclusion, no difference in total IGF‑1Ea mRNA placental expression was observed between IUGR and AGA pregnancies, likely due to heterogeneity of histological structures expressing this isoform. Negative IGF‑1Ea immunohistological expression in the extravillous trophoblast from IUGR placentas, associated with histological changes of maternal malperfusion, may reflect the involvement of this isoform in defective placentation. The presence of IGF‑1Ea peptide in the endothelium of the villous vessels in IUGR placentas may indicate a reactive autocrine regulation to compensate for malperfused villi in IUGR pregnancy by regulating angiogenesis and vasodilation. The observed sex differences in IGF‑1Ea expression between IUGR and AGA placentas may indicate interactions between sex hormones and selective IGF‑1 binding proteins in regulating IGF‑1Ea synthesis; however, this requires further elucidation.

Colorectal cancer (CRC) is one of the most common cancers worldwide. With the growing understanding of immune regulation in tumors, the complement system has been recognized as a key regulator of tumor immunity. Traditionally, the complement cascade, considered an evolutionarily conserved defense mechanism against invading pathogens, has been viewed as a crucial inhibitor of tumor progression. Complement components or activation products produced via cascade‑dependent or ‑independent processes are associated with the regulation of tumor‑associated inflammation. Various forms of complement activation products present in body fluids or inside cells, along with complement regulatory proteins and complement receptors, are involved in tumor cell growth and modulating the tumor microenvironment. In the present review, the role of the complement system in the tumor immunity of CRC is discussed. In addition, the contribution of the unconventional cascade‑independent pathway of complement activation in CRC progression is highlighted. A deeper understanding of the mechanism underlying the complement system in colitis‑associated colorectal cancer (CAC) may provide novel insights to assist the development of methods to prevent tumor progression and identify potential targets for the treatment of CAC.

Calycosin‑7‑O‑β‑D‑glucoside (CG), a major active ingredient of Astragali Radix, exerts neuroprotective effects against cerebral ischemia; however, whether the effects of CG are associated with mitochondrial protection remains unclear. The present study explored the role of CG in improving mitochondrial function in a HT22 cell model of oxygen‑glucose deprivation/reperfusion (OGD/R). The Cell Counting Kit‑8 assay, flow cytometry, immunofluorescence and western blotting were performed to investigate the effects of CG on mitochondrial function. The results demonstrated that mitochondrial function was restored after treatment with CG, as indicated by reduced mitochondrial reactive oxygen species levels, increased mitochondrial membrane potential and improved mitochondrial morphology. Overactivated mitophagy was revealed to be inhibited by the regulation of proteins involved in fission [phosphorylated‑dynamin‑related protein 1 (Drp1) and Drp1] and mitophagy (LC3, p62 and translocase of outer mitochondrial membrane 20), and mitochondrial biogenesis was demonstrated to be enhanced by increased levels of sirtuin 1 (SIRT1) and peroxisome proliferator‑activated receptor γ coactivator‑1α (PGC‑1α). In addition, neuronal apoptosis was ameliorated by CG, as determined by a decreased rate of apoptosis, and levels of caspase‑3 and Bcl‑2/Bax. In conclusion, the present study demonstrated that CG may alleviate OGD/R‑induced injury by upregulating SIRT1 and PGC‑1α protein expression, and reducing excessive mitochondrial fission and overactivation of mitophagy.

Following the publication of the above paper, it was drawn to the Editors' attention by a concerned reader that certain of the western blotting data shown in Fig. 1C and D on p. 2386 were strikingly similar to data appearing in different form in a pair of other articles written by different authors at a different research institute that had already been published elsewhere prior to the submission of this paper to . Moreover, some of the data featured in Fig. 6A and C were strikingly similar, also suggesting that the data in this figure had been misassembled. In view of the fact that the abovementioned data had already apparently been published previously, the Editor of has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Molecular Medicine Reports 17: 2384‑2392, 2018; DOI: 10.3892/mmr.2017.8152].

Small heat shock proteins (sHSPs) are common molecular chaperone proteins that function in various biological processes, and serve indispensable roles in maintaining cellular protein homeostasis and regulating the hydrolysis of unfolded proteins. HSP22 is a member of the sHSP family that is primarily expressed in the heart and skeletal muscle, as well as in various types of cancer. There have been important findings concerning the role of HSP22 in cardiovascular diseases. The aim of the present study was to provide insights into the various molecular mechanisms by which HSP22 functions in the heart, including oxidative stress, autophagy, apoptosis, the subcellular distribution of proteins and the promoting effect of proteasomes. In addition, drugs and cytokines, including geranylgeranylacetone, can exert protective effects on the heart by regulating the expression of HSP22. Based on increasingly abundant research, HSP22 may be considered a potential therapeutic target in cardiovascular diseases.

Peptidyl‑prolyl cis‑trans isomerase NIMA-interacting 1 (Pin1) is a specific phosphorylated serine/threonine-proline cis-trans isomerase, which is involved in the regulation of a variety of physiological and pathological processes, including cell cycle progression, proliferation and apoptosis. Pin1 plays a key role in tumorigenesis and tumor development and it promotes the proliferation and metastasis of cancer cells by regulating the cell cycle, signaling pathways and the function of tumor suppressors. Upregulated expression of Pin1 is closely associated with a poor prognosis in several types of cancers. Thus, Pin1 is may have potential as a novel potential biomarker for tumor diagnosis and prognosis, as well as a promising anticancer target. The aim of the present review was to discuss the mechanism of Pin1 in tumors and recent research progress in this field.

Ischemic stroke is a prevalent clinical condition that poses a significant global challenge. Developing innovative strategies to address this issue is crucial. Annexin A1 (ANXA1), a key member of the annexin superfamily, performs various functions, such as inhibiting inflammatory factor release, promoting phagocytosis, and blocking leukocyte migration. Evidence indicates that ANXA1 plays a pivotal role in the pathogenesis of ischemic stroke. The present article reviews involvement of ANXA1 in anti‑atherosclerosis, inflammatory processes, blood‑brain barrier protection, platelet aggregation and anti‑apoptotic mechanisms. The potential applications of ANXA1 in treating ischemic stroke are also explored.

Hepatocellular carcinoma (HCC) is a common cause of cancer‑related mortality and morbidity worldwide. While iodine‑125 (I) particle brachytherapy has been extensively used in the clinical treatment of various types of cancer, the precise mechanism underlying its effectiveness in treating HCC remains unclear. In the present study, MHCC‑97H cells were treated with I, after which, cell viability and proliferation were assessed using Cell Counting Kit‑8, 5‑ethynyl‑2'‑deoxyuridine and colony formation assays, cell invasion and migration were evaluated using wound healing and Transwell assays, and cell apoptosis was determined using flow cytometry. Omics data were analyzed using Kyoto Encyclopedia of Genes and Genomes, Gene Ontology and STRING analyses to observe the key genes that exhibited significant changes at the transcriptional and protein levels in MHCC‑97H cells treated with I particles. Finally, the expression levels of key genes (GPNMB, C4BPA, CTH, H1‑0 and MT2A) were verified through reverse transcription quantitative PCR. Following treatment with I, the proliferation, invasion and migration of MHCC‑97H cells were inhibited, and apoptosis was enhanced. The results of omics data analysis indicated that the biological behavior of MHCC‑97H cells treated with I was related to the expression levels of CTH and MT2A genes. These findings indicated that intervention with I radiation particles may induce changes in gene expression, potentially influencing alterations in biological characteristics. In conclusion, these insights may shed light on the underlying mechanisms of I radiation particle therapy in HCC and offer novel targets for HCC treatment.

Asiasarum root and rhizome () is commonly used as a diaphoretic. Due to its warm and pungent characteristics in traditional Chinese and Korean medicine, it is considered as having the potential to prevent disease. The present study investigated the effects of extract on the symptoms of obesity in mice, and the regulation of energy metabolism in the liver and skeletal muscle tissues. In addition, to identify the potential molecular targets and signaling pathways involved in the mechanism of action of extract in obesity, network pharmacological and molecular docking analysis was performed. studies demonstrated that extract significantly increased the expression of regulators of energy metabolism [sirtuin 1 (SIRT1), peroxisome proliferator‑activated receptor γ coactivator 1‑α (PGC1α), nuclear respiratory factor 1, AMP‑activated protein kinase (AMPK) and glucose transporter type 4 (GLUT4)] and myogenic regulatory factors (MyoD, myogenin and myosin heavy chain) in C2C12 myotubes. Furthermore, the in vivo studies demonstrated that extract could reduce increases in body weight, and the levels of blood glucose, insulin, total cholesterol, triglycerides and low‑density lipoprotein cholesterol in the sera of obese mice. extract also improved pathological changes in the liver and pancreatic tissues of obese mice, and significantly increased the ratio of brown fat mass to body weight. In addition, extract reversed the expression of energy metabolism regulators and myogenic regulatory factors in the gastrocnemius tissues of obese mice. extract also activated the expression of SIRT1, PGC1α and AMPK in the liver tissues of obese mice. These findings indicated that extract may exert anti‑obesity effects, such as body weight loss, decreases in lipid metabolite levels, and inhibition of pancreatic and liver damage. Using network pharmacological analysis, the mechanisms underlying the effects of extract on the regulation of energy metabolism were explored, particularly in skeletal muscle and liver tissues.

The present study aimed to investigate the cardioprotective effects of acteoside (AC) on myocardial ischemia‑reperfusion injury (MIRI). To meet this aim, a network pharmacological analysis was conducted to search for key genes and signaling pathways associated with AC and MIRI. The infarct size of the rat heart was evaluated using 2,3,5‑triphenyltetrazolium chloride staining, and the serum levels of creatine kinase MB isoenzyme, cardiac troponin I, malondialdehyde and superoxide dismutase were subsequently detected in an experiment. The inhibitory effect of AC on oxidative stress was further confirmed by assessing the intracellular accumulation of reactive oxygen species (ROS). Hematoxylin and eosin staining was subsequently carried out to observe cardiac histopathological damage. The anti‑apoptotic effects of AC were determined using terminal deoxynucleotidyl‑transferase‑mediated dUTP nick end labeling assay and Hoechst 33342 staining, and the expression levels of apoptosis‑associated proteins in the myocardial tissue were assessed using immunohistochemical analysis. In addition, cell viability was determined using a Cell Counting Kit‑8 assay, and the expression levels of key target proteins associated with AC and MIRI were detected by western blot analysis. The results suggested that pretreatment with AC could mitigate MIRI‑induced myocardial damage, oxidative stress and apoptosis. The anti‑apoptotic effects of AC were associated with elevated Bcl‑2 levels, and reduced caspase‑3 and Bax expression levels in myocardial tissue. , AC pretreatment both led to an increased rate of cell survival and alleviated oxidative stress, as demonstrated by a decreased level of intracellular ROS accumulation. Moreover, guided by the network pharmacological analysis, heat‑shock protein 90AA1 (HSP90AA1) and the phosphoinositide 3‑kinase (PI3K)/serine‑threonine protein kinase (Akt) signaling pathway emerged as key targets for the action of AC against MIRI. Furthermore, the western blot analysis results showed that pretreatment with AC led to a significant increase in the activity of the PI3K/Akt signaling pathway, in addition to increased expression levels of glycogen synthase kinase‑3β and HSP90AA1. Taken together, the findings of the present study revealed that AC may exert cardioprotective effects on MIRI through suppressing apoptosis and oxidative stress by regulating the expression and activity of key proteins.

Renowned as a highly invasive and lethal tumor derived from neural stem cells in the central nervous system, glioblastoma (GBM) exhibits substantial histopathological variation and genomic complexity, which drive its rapid progression and therapeutic resistance. Alterations in mitochondrial DNA (mtDNA) copy number (CN) serve a crucial role in GBM development and progression, affecting various aspects of tumor biology, including energy production, oxidative stress regulation and cellular adaptability. Fluctuations in mtDNA levels, whether elevated or diminished, can impair mitochondrial function, potentially disrupting oxidative phosphorylation and amplifying reactive oxygen species generation, thereby fueling tumor growth and influencing treatment responses. Understanding the mechanisms of mtDNA‑CN variations, and their interplay with genetic and environmental elements in the tumor microenvironment, is essential for advancing diagnostic and therapeutic strategies. Targeting mtDNA alterations could strengthen treatment efficacy, mitigate resistance and ultimately enhance the prognosis of patients with this aggressive brain tumor. The present review summarizes the existing literature on mtDNA alterations, specifically emphasizing variations in mtDNA‑CN and their association with GBM by surveying articles published between 1996 and 2024, sourced from databases such as Scopus, PubMed and Google Scholar. In addition, the review provides a brief overview of mitochondrial genome architecture, knowledge regarding the regulation of mtDNA integrity and CN, and how mitochondria significantly impact GBM tumorigenesis. This review further presents information on therapeutic approaches for restoring mtDNA‑CN that contribute to optimized mitochondrial function and improved health outcomes.

The present study investigated the sensitization mechanism of triptolide (TPL) in esophageal squamous cell carcinoma (ESCC) resistant to cis‑diamminedichloroplatinum (CDDP). CDDP‑resistant TE‑1/CDDP and KYSE30/CDDP cells were created using an incremental drug concentration approach. TPL and CDDP treatment conditions were screened based on the Cell Counting Kit‑8 cell viability assay and cell proliferation was detected using 5‑ethynyl‑2'‑deoxyuridine and clone formation assays. Flow cytometry combined with Hoechst 33258 staining was used to assess cell cycle progression and apoptosis. Scratch healing assay, Transwell assay and western blotting were used to investigate the malignant behaviors of the cells. Changes in cellular glycolysis were investigated by measuring glucose uptake, lactate production and the levels of related regulatory factors. Changes in mitochondrial function were examined by detecting ATP and reactive oxygen species levels, as well as mitochondrial membrane potential and cytochrome c release. Furthermore, a nude mouse subcutaneous graft tumor model assay was used to assess the in vivo effect of TPL. dosages of TPL and CDDP were tested at 2 nM and 4 M, respectively. Notably, TPL decreased the proliferation, migration, invasion and epithelial‑mesenchymal transition of CDDP‑resistant ESCC cells, increased their apoptosis and significantly suppressed tumor growth in a nude mouse model of ESCC. TPL was shown to have a strong CDDP‑sensitizing effect and and its mechanism may involve inhibiting anaerobic glycolysis and causing mitochondrial energy metabolism impairment to induce apoptosis. In conclusion, TPL may be considered a potential CDDP sensitizer with substantial clinical implications for ESCC therapy.

Endometrial carcinoma (EC) is one of the leading causes of mortality in women. Metabolic disorders, such as abnormal fatty acid metabolism (FAM), are considered to be indicators of tumorigenesis. However, to the best of our knowledge, the relationship between EC and FAM remains unclear. The process of FAM is associated with the function of immune cells, thus samples from The Cancer Genome Atlas were grouped according to immune infiltration levels. Subsequently, prognostic gene signatures were constructed based on selected FAM‑associated genes. The signature effect was validated, and enrichment analyses were conducted based on sample classification. Nomograms were used to predict survival, merging clinical data and the gene signature. Samples were divided into high‑ and low‑risk groups based on the gene signature. The survival status, clinical characteristics, enrichment analysis and immune infiltration were significantly different between high‑ and low‑risk groups. According to the nomogram, low microsatellite instability‑high as well as a high tumor mutation burden can be observed in the low‑nomo‑score group. Immune checkpoint inhibitor‑associated genes were differentially expressed between groups and 35 sensitive compounds were identified. Comprehensive bioinformatics analysis in EC revealed potential roles of FAM in tumorigenesis, the tumor microenvironment and prognosis, suggesting that FAM‑associated signatures are promising biomarkers for EC. These findings may improve the understanding of FAM in EC and pave the way for a more accurate assessment of prognosis and immunotherapy outcomes.

Aseptic loosening (AL) of artificial hip joints is the most common complication following hip replacement surgery. A total of eight patients diagnosed with AL following total hip arthroplasty (THA) undergoing total hip replacement and eight control patients diagnosed with avascular necrosis of femoral head (ANFH) or femoral neck fracture undergoing THA were enrolled. The samples of the AL group were from synovial tissue surrounding the lining/head/neck of the prosthesis, and the samples of the control group were from the synovium in the joint cavity. The present study utilized second‑generation high‑throughput sequencing and mass spectrometry to detect differentially expressed genes, proteins and metabolites in the samples, as well as Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. Key genes cytokine receptor‑like factor‑1 (CRLF1) and glutathione‑S transferase 1 (GSTM1) expression levels were verified by reverse transcription‑quantitative PCR and western blotting. The integrated transcriptomics, proteomics and untargeted metabolomics analyses revealed characteristic metabolite changes (biosynthesis of guanine, L‑glycine and adenosine) and decreased CRLF1 and GSTM1 in AL, which were primarily associated with amino acid metabolism and lipid metabolism. In summary, the present study may uncover the underlying mechanisms of AL pathology and provide stable and accurate biomarkers for early warning and diagnosis.

Insulin‑like growth factor 2 mRNA binding protein 2 (IGF2BP2) is an RNA binding protein that functions as an N‑methyladenosine reader. It regulates various biological processes in human cancers by affecting the stability and expression of target RNA transcripts, including coding RNAs and non‑coding RNAs (ncRNAs). Numerous studies have shown that IGF2BP2 expression is aberrantly increased in various types of cancer and plays multifaceted roles in the development and progression of human cancers. In the present review, the clinical importance of IGF2BP2 is summarized and its involvement in the regulation of biological processes, including proliferation, metastasis, chemoresistance, metabolism, tumor immunity, stemness and cell death, in human cancers is discussed. The chemical compounds that have been developed as IGF2BP2 inhibitors are also detailed. As ncRNAs are now important potential therapeutic agents for cancer treatment, the microRNAs that have been reported to directly target and inhibit IGF2BP2 expression in cancers are also described. In summary, by reviewing the latest literature, the present study aimed to highlight the clinical importance and physiological functions of IGF2BP2 in human cancer, with a focus on the great potential of IGF2BP2 as a target for inhibitor development. The present review may inspire new ideas for future studies on IGF2BP2, which may serve as a specific therapeutic target in cancer.

Most psychiatric disorders are heterogeneous and are attributed to the synergistic action of a multitude of factors. It is generally accepted that psychiatric disorders are the outcome of interactions between genetic predisposition and environmental perturbations, which involve psychosocial stress, or alterations in the physiological state of the organism. A number of hypotheses have been presented on such environmental influences that may include direct insults such as injury, malnutrition and hostile living conditions, or indirect sequelae following infection from viruses such as influenza, arboviruses, enteroviruses and several herpesviruses, or the differential expression of human endogenous retroviruses. It is known that the concept of viruses is far more extensive than their perception as mere agents of acute infections, or chronic debilitating diseases, such as AIDS or some forms of cancer. Notably, an apparent causal connection between viruses and the pathophysiology of diseases has been suggested; however, it remains unclear as to how to establish this causal connection. There are inherent difficulties in answering this question with certainty, which may be due to the multitude of genetic and environmental influences that can lead to psychopathology; the latent state of chronic infection exhibited by a number of neurotropic viruses; the late onset of psychiatric disorders with respect to the acute phase of viral infection at which detection tests would be successful; the complexity of the virome; and the existence of thousands of viral species. The present review aims to provide an outline of the conclusions that have thus far been reached regarding a possible association between viral infection and psychiatric disease, and the obstacles confronted during the quest for the truth behind the role of viruses.

Cartilage‑hair hypoplasia (CHH) is an autosomal recessive form of metaphyseal chondrodysplasia caused by RNA component of mitochondrial RNA processing endoribonuclease (RMRP) gene variants; however, its molecular etiology remains unclear. Whole‑exome sequencing was performed to detect possible pathogenic variants in a patient with a typical short stature and sparse hair. A co‑segregation analysis was also conducted and variants in the family members of the patient were confirmed by Sanger sequencing. A novel compound heterozygous variant in RMRP (NR_003051.4: n.‑21_‑2dup and n.197C>T) was identified in the affected patient. Data from 2 years and 4 months of follow‑up showed a positive effect of growth hormone (GH) therapy on height. Subsequently, two gene expression profiles associated with CHH were obtained from the EMBL‑EBI ENA and ArrayExpress databases. Differentially expressed genes between patients with CHH and healthy controls were selected using R software and were subjected to core analysis using ingenuity pathway analysis (IPA) software. IPA core analysis showed that the 'cell cycle checkpoints' was the most prominent canonical pathway, and the top enriched diseases and functions included various types of cancer, immunological diseases, development disorders and respiratory diseases. The integrative analysis displayed that RMRP can regulate the aberrant expression of downstream targets mainly via the transcription factor TP53, which results in the inhibition of 'cell cycle checkpoints'; eventually, functions associated with the CHH phenotype, such as 'growth failure or short stature' are activated. In conclusion, novel disease‑causing genetic variants of RMRP expand the genetic etiology of CHH, which must be clinically differentiated from achondroplasia. The findings of the present study provide new insights into the mechanisms underlying CHH.