The Role of AKR1B10 in Physiology and Pathophysiology

Berberine directly targets AKR1B10 protein to modulate lipid and glucose metabolism disorders in NAFLD

ETHNOPHARMACOLOGICAL RELEVANCE

Berberine (BBR) is the main active component from Coptidis rhizome, a well-known Chinese herbal medicine used for metabolic diseases, especially diabetes for thousands of years. BBR has been reported to cure various metabolic disorders, such as nonalcoholic fatty liver disease (NAFLD). However, the direct proteomic targets and underlying molecular mechanism of BBR against NAFLD remain less understood.

AIM OF THE STUDY

To investigate the direct target and corresponding molecular mechanism of BBR on NAFLD is the aim of the current study.

MATERIALS AND METHODS

High-fat diet (HFD)-fed mice and oleic acid (OA) stimulated HepG2 cells were utilized to verify the beneficial impacts of BBR on glycolipid metabolism profiles. The click chemistry in proteomics, DARTS, CETSA, SPR and fluorescence co-localization analysis were conducted to identify the targets of BBR for NAFLD. RNA-seq and shRNA/siRNA were used to investigate the downstream pathways of the target.

RESULTS

BBR improved hepatic steatosis, ameliorated insulin resistance, and reduced TG levels in the NAFLD models. Importantly, Aldo-keto reductase 1B10 (AKR1B10) was first proved as the target of BBR for NAFLD. The gene expression of AKR1B10 increased significantly in the NAFLD patients' liver tissue. We further demonstrated that HFD and OA increased AKR1B10 expression in the C57BL/6 mice's liver and HepG2 cells, respectively, whereas BBR decreased the expression and activities of AKR1B10. Moreover, the knockdown of AKR1B10 by applying shRNA/siRNA profoundly impacted the beneficial effects on the pathogenesis of NAFLD by BBR. Meanwhile, the changes in various proteins (ACC1, CPT-1, GLUT2, etc.) are responsible for hepatic lipogenesis, fatty acid oxidation, glucose uptake, etc. by BBR were reversed by the knockdown of AKR1B10. Additionally, RNA-seq was used to identify the downstream pathway of AKR1B10 by examining the gene expression of liver tissues from HFD-fed mice. Our findings revealed that BBR markedly increased the protein levels of PPARα while downregulating the expression of PPARγ. However, various proteins of PPAR signaling pathways remained unaffected post the knockdown of AKR1B10.

CONCLUSIONS

BBR alleviated NAFLD via mediating PPAR signaling pathways through targeting AKR1B10. This study proved that AKR1B10 is a novel target of BBR for NAFLD treatment and helps to find new targets for the treatment of NAFLD by using active natural compounds isolated from traditional herbal medicines as the probe.

CHES1 modulated tumorigenesis and senescence of pancreas cancer cells through repressing AKR1B10

Pancreatic ductal adenocarcinoma (PDAC), is characteristic by a heterogeneous tumor microenvironment and gene mutations, conveys a dismal prognosis and low response to chemotherapy and immunotherapy. Here, we found that checkpoint suppressor 1 (CHES1) served as a tumor repressor in PDAC and was associated with patient prognosis. Functional experiments indicated that CHES1 suppressed the proliferation and invasion of PDAC by modulating cellular senescence. To further identify the downstream factor of CHES1 in PDAC, label-free quantitative proteomics analysis was conducted, which showed that the oncogenic Aldo-keto reductase 1B10 (AKR1B10) was transcriptionally repressed by CHES1 in PDAC. And AKR1B10 facilitated the malignant activity and repressed senescent phenotype of PDAC cells. Moreover, pharmaceutical inhibition of AKR1B10 with Oleanolic acid (OA) significantly induced tumor regression and sensitized PDAC cells to gemcitabine, and this combined therapy did not cause obvious side effects. Rescued experiments revealed that CHES1 regulated the tumorigenesis and gemcitabine sensitivity through AKR1B10-mediated senescence in PDAC. In summary, this study revealed that the CHES1/AKR1B10 axis modulated the progression and cellular senescence in PDAC, which might provide revenues for drug-targeting and senescence-inducing therapies for PDAC.

Nicotinate-curcumin improves NASH by inhibiting the AKR1B10/ACCα-mediated triglyceride synthesis

BACKGROUND

Nonalcoholic steatohepatitis (NASH) is a prevalent chronic liver condition. However, the potential therapeutic benefits and underlying mechanism of nicotinate-curcumin (NC) in the treatment of NASH remain uncertain.

METHODS

A rat model of NASH induced by a high-fat and high-fructose diet was treated with nicotinate-curcumin (NC, 20, 40 mg·kg- 1), curcumin (Cur, 40 mg·kg- 1) and metformin (Met, 50 mg·kg- 1) for a duration of 4 weeks. The interaction between NASH, Cur and Aldo-Keto reductase family 1 member B10 (AKR1B10) was filter and analyzed using network pharmacology. The interaction of Cur, NC and AKR1B10 was analyzed using molecular docking techniques, and the binding energy of Cur and NC with AKR1B10 was compared. HepG2 cells were induced by Ox-LDL (25 µg·ml- 1, 24 h) in high glucose medium. NC (20µM, 40µM), Cur (40µM) Met (150µM) and epalrestat (Epa, 75µM) were administered individually. The activities of ALT, AST, ALP and the levels of LDL, HDL, TG, TC and FFA in serum were quantified using a chemiluminescence assay. Based on the changes in the above indicators, score according to NAS standards. The activities of Acetyl-CoA and Malonyl-CoA were measured using an ELISA assay. And the expression and cellular localization of AKR1B10 and Acetyl-CoA carboxylase (ACCα) in HepG2 cells were detected by Western blotting and immunofluorescence.

RESULTS

The results of the animal experiments demonstrated that NASH rat model induced by a high-fat and high-fructose diet exhibited pronounced dysfunction in liver function and lipid metabolism. Additionally, there was a significant increase in serum levels of FFA and TG, as well as elevated expression of AKR1B10 and ACCα, and heightened activity of Acetyl-CoA and Malonyl-CoA in liver tissue. The administration of NC showed to enhance liver function in rats with NASH, leading to reductions in ALT, AST and ALP levels, and decrease in blood lipid and significant inhibition of FFA and TG synthesis in the liver. Network pharmacological analysis identified AKR1B10 and ACCα as potential targets for NASH treatment. Molecular docking studies revealed that both Cur and NC are capable of binding to AKR1B10, with NC exhibiting a stronger binding energy to AKR1B10. Western blot analysis demonstrated an upregulation in the expression of AKR1B10 and ACCα in the liver tissue of NASH rats, accompanied by elevated Acetyl-CoA and Malonyl-CoA activity, and increased levels of FFA and TG. The results of the HepG2 cell experiments induced by Ox-LDL suggest that NC significantly inhibited the expression and co-localization of AKR1B10 and ACCα, while also reduced levels of TC and LDL-C and increased level of HDL-C. These effects are accompanied by a decrease in the activities of ACCα and Malonyl-CoA, and levels of FFA and TG. Furthermore, the impact of NC appears to be more pronounced compared to Cur.

CONCLUSION

NC could effectively treat NASH and improve liver function and lipid metabolism disorder. The mechanism of NC is related to the inhibition of AKR1B10/ACCα pathway and FFA/TG synthesis of liver.

Machine learning-based algorithm identifies key mitochondria-related genes in non-alcoholic steatohepatitis

BACKGROUND

Evidence suggests that hepatocyte mitochondrial dysfunction leads to abnormal lipid metabolism, redox imbalance, and programmed cell death, driving the onset and progression of non-alcoholic steatohepatitis (NASH). Identifying hub mitochondrial genes linked to NASH may unveil potential therapeutic targets.

METHODS

Mitochondrial hub genes implicated in NASH were identified via analysis using 134 algorithms.

RESULTS

The Random Forest algorithm (RF), the most effective among the 134 algorithms, identified three genes: Aldo-keto reductase family 1 member B10 (AKR1B10), thymidylate synthase (TYMS), and triggering receptor expressed in myeloid cell 2 (TREM2). They were upregulated and positively associated with genes promoting inflammation, genes involved in lipid synthesis, fibrosis, and nonalcoholic steatohepatitis activity scores in patients with NASH. Moreover, using these three genes, patients with NASH were accurately categorized into cluster 1, exhibiting heightened disease severity, and cluster 2, distinguished by milder disease activity.

CONCLUSION

These three genes are pivotal mitochondrial genes implicated in NASH progression.

AKR1B10 accelerates glycolysis through binding HK2 to promote the malignant progression of oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC) remains a rampant oral cavity neoplasm with high degree of aggressiveness. Aldo-keto reductase 1B10 (AKR1B10) that is an oxidoreductase dependent on nicotinamide adenine dinucleotide phosphate (NADPH) has been introduced to possess prognostic potential in OSCC. The present work was focused on specifying the involvement of AKR1B10 in the process of OSCC and its latent functional mechanism.

METHODS

AKR1B10 expression in OSCC tissues and cells were detected by RT-qPCR and Western blot analysis. CCK-8 method, EdU staining, wound healing and transwell assays respectively assayed cell viability, proliferation, migration and invasion. Immunofluorescence staining and Western blot evaluated epithelial mesenchymal transition (EMT). Adenosine triphosphate (ATP) contents, glucose consumption and extracellular acidification rate (ECAR) were measured by relevant commercially available kits and Seahorse XF96 Glycolysis Analyzer, severally. The expressions of proteins associated with metastasis and glycolysis were examined with Western blot. Co-IP assay confirmed the binding between AKR1B10 and hexokinase 2 (HK2).

RESULTS

It was observed that AKR1B10 expression was increased in OSCC tissues and cells. After AKR1B10 was knocked down, the proliferation, migration, invasion and EMT of OSCC cells were all hampered. Additionally, AKR1B10 silencing suppressed glycolysis and bound to HK2 in OSCC cells. Up-regulation of HK2 partially abolished the hampered glycolysis, proliferation, migration, invasion and EMT of AKR1B10-silenced OSCC cells.

CONCLUSION

To sum up, AKR1B10 could bind to HK2 to accelerate glycolysis, thereby facilitating the proliferation, migration, invasion and EMT of OSCC cells.

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

Unveiling the Anticancer Mechanism of Echinops davuricus: Isolation and Evaluation of AKR1B10 Inhibitors

Five compounds (1-5), one long-chain fatty acid (1), two thiophenes (2 and 3), one alkaloid (4), and one phenyl ester (5), were isolated from the aerial part of Echinops davuricus. The structures of the products were established by performing detailed nuclear magnetic resonance (NMR) analysis, and the structure of compound 1 was determined via high-resolution electrospray ionization mass spectrometry (HRESIMS) and NMR. Compounds 1, 4, and 5 were isolated from Echinops davuricus for the first time. Based on network pharmacology methods, AKR1B10 was selected as a key anticancer target. Compounds 1 and 5 exhibited significant AKR1B10 inhibitory activities, with IC50 values of 156.0±1.00 and 146.2±1.50 nM, respectively, with epalrestat used as the positive control (81.09±0.61 nM). Additionally, the interactions between the active compounds and AKR1B10 were evaluated via molecular docking. Ultimately, the GO and KEGG enrichment analysis indicated that the key signaling pathways associated with the active compounds may be related to the PI3K-Akt, MAPK, apoptotic, cellular senescence, and TNF signaling pathways and the human diseases corresponding to the targets are cancer. Our study reveals for the first time the anticancer properties of Echinops davuricus and provides a comprehensive understanding of its application in traditional medicine.

A three-level regulatory mechanism of the aldo-keto reductase subfamily AKR12D

Modulation of protein function through allosteric regulation is central in biology, but biomacromolecular systems involving multiple subunits and ligands may exhibit complex regulatory mechanisms at different levels, which remain poorly understood. Here, we discover an aldo-keto reductase termed AKRtyl and present its three-level regulatory mechanism. Specifically, by combining steady-state and transient kinetics, X-ray crystallography and molecular dynamics simulation, we demonstrate that AKRtyl exhibits a positive synergy mediated by an unusual Monod-Wyman-Changeux (MWC) paradigm of allosteric regulation at low concentrations of the cofactor NADPH, but an inhibitory effect at high concentrations is observed. While the substrate tylosin binds at a remote allosteric site with positive cooperativity. We further reveal that these regulatory mechanisms are conserved in AKR12D subfamily, and that substrate cooperativity is common in AKRs across three kingdoms of life. This work provides an intriguing example for understanding complex allosteric regulatory networks.

Development of AKR1B10 inhibitors from Ajuga nipponensis based on diseases and targets

Ten compounds (1-10) including one new neoclerodane diterpenoid (1) and nine known compounds were isolated from the whole plants of Ajuga nipponensis. Their structures were established by performing detailed analysis of NMR, the structure of 1 was determined using HRESIMS, 1D and 2D NMR, UV, and IR. Compounds 1 and 4-10 were isolated from Ajuga nipponensis for the first time. And it was the first time to report compounds 9 and 10 as natural products. Based on network pharmacology methods, 45 key targets were selected, which were compounds mapping to diseases. And compounds 2, 3, 7, and a (ajugacumbin B) exhibited excellent AKR1B10 inhibitory activities, with IC50 values of 53.05 ± 0.75, 87.22 ± 0.85, 61.85 ± 0.66, and 85.19±1.02 nM respectively, with Epalrestat used as the positive control (82.09 ± 1.62 nM). Additionally, the interaction between active compounds and AKR1B10 had been discussed according to the molecular docking results. Ultimately, the analysis of GO and KEGG enrichment indicated that the key signaling pathway of the active compounds may be related to prostate cancer. Our study results demonstrate the hypoglycemic and anti-tumor properties of A. nipponensis for the first time, and provide a comprehensive understanding of its application in traditional medicine. Furthermore, this article establishes a reference for further research on the optimized experimental design of novel AKR1B10 inhibitors.

Combining diabetes, sex, and menopause as meaningful clinical features associated with NASH and liver fibrosis in individuals with class II and III obesity: A retrospective cohort study

OBJECTIVE

Steatotic liver disease (SLD) is frequent in individuals with obesity. In this study, type 2 diabetes (T2D), sex, and menopausal status were combined to refine the stratification of obesity regarding the risk of advanced SLD and gain further insight into disease physiopathology.

METHODS

This study enrolled 1446 participants with obesity from the ABOS cohort (NCT01129297), who underwent extensive phenotyping, including liver histology and transcriptome profiling. Hierarchical clustering was applied to classify participants. The prevalence of metabolic disorders associated with steatohepatitis (NASH) and liver fibrosis (F ≥ 2) was determined within each identified subgroup and aligned to clinical and biological characteristics.

RESULTS

The prevalence of NASH and F ≥ 2 was, respectively, 9.5% (N = 138/1446) and 11.7% (N = 159/1365) in the overall population, 20.3% (N = 107/726) and 21.1% (N = 106/502) in T2D patients, and 3.4% (N = 31/920) and 6.1% (N = 53/863) in non-T2D patients. NASH and F ≥ 2 prevalence was 15.4% (33/215) and 15.5% (32/206) among premenopausal women with T2D vs. 29.5% (33/112) and 30.3% (N = 36/119) in postmenopausal women with T2D (p < 0.01); and 21.0% (21/100) / 27.0% (24/89) in men with T2D ≥ age 50 years and 17.9% (17/95) / 18.5% (17/92) in men with T2D < age 50 years (NS). The distinct contribution of menopause was confirmed by the interaction between sex and age with respect to NASH among T2D patients (p = 0.048). Finally, several NASH-associated biological traits (lower platelet count; higher serum uric acid; gamma-glutamyl transferase; aspartate aminotransferase) and liver expressed genes AKR1B10 and CCL20 were significantly associated with menopause in women with T2D but not with age in men with T2D.

CONCLUSIONS

This study unveiled a remarkably high prevalence of advanced SLD after menopause in women with T2D, associated with a dysfunctional biological liver profile.

Diagnostic value of aldo‑keto reductase family 1 member B10 in human nasopharyngeal carcinoma

Aldo-keto reductase family 1 member B10 (AKR1B10) is a potential marker of several types of cancer; however, the role of AKR1B10 in nasopharyngeal carcinoma (NPC) remains unclear. In the present study, AKR1B10 RNA-seq data and clinical information were obtained from The Cancer Genome Atlas head and neck squamous cell carcinoma (HNSCC) database to evaluate the role of AKR1B10 in HNSCC. There was no statistically significant difference in the expression of AKR1B10 between HNSCC tissues and adjacent normal tissues, and high AKR1B10 expression was not associated with poor overall survival according to the public database. The present study further examined the role of AKR1B10 in patients with NPC using data obtained from the Gene Expression Omnibus database. Analysis of the GSE53819 and GSE61218 datasets showed that the there were no significant differences in the expression levels of AKR1B10 between NPC tissues and normal tissues. However, analysis of the GSE103611 dataset indicated that AKR1B10 may be associated with distance metastasis following radical treatment in NPC. Finally, serum samples from patients with NPC and healthy controls were collected and analyzed. The results revealed that AKR1B10 levels were significantly increased in samples from patients with NPC compared with those from healthy controls, and the area under the receiver operating characteristic curve was 0.909. In conclusion, unlike tissue AKR1B10 expression, serum AKR1B10 levels may be a promising biomarker for the diagnosis of NPC.

AKR1B10 regulates M2 macrophage polarization to promote the malignant phenotype of gastric cancer

BACKGROUND

Immunotherapy has brought new hope to gastric cancer (GC) patients. Exploring the immune infiltration pattern in GC and the key molecules is critical for optimizing the efficacy of immunotherapy. Aldo-keto reductase family 1 member B10 (AKR1B10) is an inflammatory regulator and is closely related to the prognosis of patients with GC. However, the function of AKR1B10 in GC remains unclear.

METHODS

In the present study, the CIBERSORT algorithm was used to analyze the immune infiltration pattern in 373 samples in the Cancer Genome Atlas (TCGA) database. Differentially expressed genes (DEGs) were seared by combing the TCGA database and the Gene Expression Omnibus (GEO) database, and the key molecule AKR1B10 was identified by weighted gene coexpression network analysis (WGCNA). The biological functions of AKR1B10 in stomach adenocarcinoma (STAD) were investigated in vitro.

RESULTS

Macrophage polarization was the main immune infiltration pattern in GC, and the state of macrophage polarization was closely related to the pathological grading of GC and the clinical stage of patients. AKR1B10, MUC5AC, TFF2, GKN1, and PGC were significantly down-regulated in GC tissues. Low AKR1B10 expression induced M2 macrophage polarization and promoted the malignant phenotype of GC.

CONCLUSION

M2 macrophage polarization is the main immune infiltration pattern in GC. Low AKR1B10 expression induces M2 macrophage polarization and promotes the malignant transformation of GC.

Inhibitory selectivity to the AKR1B10 and aldose reductase (AR): insight from molecular dynamics simulations and free energy calculations

AKR1B10 is over-expressed in many cancer types and is related to chemotherapy resistance, which makes AKR1B10 a potential anti-cancer target. The high similarity of the protein structure between AKR1B10 and AR makes it difficult to develop highly selective inhibitors against AKR1B10. Understanding the interaction between AKR1B10 and inhibitors is very important for designing selective inhibitors of AKR1B10. In this study, Fidarestat, Zopolrestat, MK184 and MK204 bound to AKR1B10 and AR were used to investigate the selectivity mechanism. The results of MM/PBSA calculations show that van der Waals and electrostatic interaction provide the main contributions of the binding free energy. The hydrogen bonding between residues Y49 and H111 and inhibitors plays a pivotal role in contributing to the high inhibitory activity of AKR1B10 inhibitors. The π-π stacking interaction between residue W112 and inhibitor also plays a key role in the stability of inhibitors and AKR1B10, but W112 should keep its natural conformation to stabilize the inhibitor-AKR1B10 complex. Highly selective AKR1B10 inhibitors should have a bulky moiety like a phenyl group, which can change its binding with ABP in binding with AR and cannot change its binding with AKR1B10. The free energy decomposition shows that residues W21, V48, Y49, K78, W80, H111, R298 and V302 are beneficial to the stability of the inhibitor-AKR1B10. Our work will provide an important in silico basis for researchers to develop highly selective inhibitors of AKR1B10.

Warburg effect enhanced by AKR1B10 promotes acquired resistance to pemetrexed in lung cancer-derived brain metastasis

BACKGROUND

Resistance to pemetrexed (PEM), a rare chemotherapeutic agent that can efficiently cross the blood-brain barrier, limits the therapeutic efficacy for patients with lung cancer brain metastasis (BM). Aldo-keto reductase family 1 B10 (AKR1B10) was recently found to be elevated in lung cancer BM. The link between AKR1B10 and BM-acquired PEM is unknown.

METHODS

PEM drug-sensitivity was assessed in the preclinical BM model of PC9 lung adenocarcinoma cells and the BM cells with or without AKR1B10 interference in vitro and in vivo. Metabolic reprogramming of BM attributed to AKR1B10 was identified by chromatography-mass spectrometry (GC-MS) metabolomics, and the mechanism of how AKR1B10 mediates PEM chemoresistance via a way of modified metabolism was revealed by RNA sequencing as well as further molecular biology experimental approaches.

RESULTS

The lung cancer brain metastatic subpopulation cells (PC9-BrM3) exhibited significant resistance to PEM and silencing AKR1B10 in PC9-BrM3 increased the PEM sensitivity in vitro and in vivo. Metabolic profiling revealed that AKR1B10 prominently facilitated the Warburg metabolism characterized by the overproduction of lactate. Glycolysis regulated by AKR1B10 is vital for the resistance to PEM. In mechanism, AKR1B10 promoted glycolysis by regulating the expression of lactate dehydrogenase (LDHA) and the increased lactate, acts as a precursor that stimulates histone lactylation (H4K12la), activated the transcription of CCNB1 and accelerated the DNA replication and cell cycle.

CONCLUSIONS

Our finding demonstrates that AKR1B10/glycolysis/H4K12la/CCNB1 promotes acquired PEM chemoresistance in lung cancer BM, providing novel strategies to sensitize PEM response in the treatment of lung cancer patients suffering from BM.

Exome Survey and Candidate Gene Re-Sequencing Identifies Novel Exstrophy Candidate Genes and Implicates LZTR1 in Disease Formation

BACKGROUND

The bladder exstrophy-epispadias complex (BEEC) is a spectrum of congenital abnormalities that involves the abdominal wall, the bony pelvis, the urinary tract, the external genitalia, and, in severe cases, the gastrointestinal tract as well.

METHODS

Herein, we performed an exome analysis of case-parent trios with cloacal exstrophy (CE), the most severe form of the BEEC. Furthermore, we surveyed the exome of a sib-pair presenting with classic bladder exstrophy (CBE) and epispadias (E) only. Moreover, we performed large-scale re-sequencing of CBE individuals for novel candidate genes that were derived from the current exome analysis, as well as for previously reported candidate genes within the CBE phenocritical region, 22q11.2.

RESULTS

The exome survey in the CE case-parent trios identified two candidate genes harboring de novo variants (NR1H2, GKAP1), four candidate genes with autosomal-recessive biallelic variants (AKR1B10, CLSTN3, NDST4, PLEKHB1) and one candidate gene with suggestive uniparental disomy (SVEP1). However, re-sequencing did not identify any additional variant carriers in these candidate genes. Analysis of the affected sib-pair revealed no candidate gene. Re-sequencing of the genes within the 22q11.2 CBE phenocritical region identified two highly conserved frameshift variants that led to early termination in two independent CBE males, in LZTR1 (c.978_985del, p.Ser327fster6) and in SLC7A4 (c.1087delC, p.Arg363fster68).

CONCLUSIONS

According to previous studies, our study further implicates LZTR1 in CBE formation. Exome analysis-derived candidate genes from CE individuals may not represent a frequent indicator for other BEEC phenotypes and warrant molecular analysis before their involvement in disease formation can be assumed.

The Effects and Regulatory Mechanism of Casein-Derived Peptide VLPVPQK in Alleviating Insulin Resistance of HepG2 Cells

The liver plays a key role in keeping the homeostasis of glucose and lipid metabolism. Insulin resistance of the liver induced by extra glucose and lipid ingestion contributes greatly to chronic metabolic disease, which is greatly threatening to human health. The small peptide, VLPVPQK, originating from casein hydrolysates of milk, shows various health-promoting functions. However, the effects of VLPVPQK on metabolic disorders of the liver are still not fully understood. Therefore, in the present study, the effects and regulatory mechanism of VLPVPQK on insulin-resistant HepG2 cells was further investigated. The results showed that VLPVPQK exerted strong scavenging capacities against various free radicals, including oxygen radicals, hydroxyl radicals, and cellular reactive oxygen species. In addition, supplementation of VLPVPQK (62.5, 125, and 250 μM) significantly reversed the high glucose and fat (30 mM glucose and 0.2 mM palmitic acid) induced decrement of glucose uptake in HepG2 cells without affecting cell viability. Furthermore, VLPVPQK intervention affected the transcriptomic profiling of the cells. The differentially expressed (DE) genes (FDR < 0.05, and absolute fold change (FC) > 1.5) between VLPVPQK and the model group were mostly enriched in the carbohydrate metabolism-related KEGG pathways. Interestingly, the expression of two core genes (HKDC1 and G6PC1) involved in the above pathways was dramatically elevated after VLPVPQK intervention, which played a key role in regulating glucose metabolism. Furthermore, supplementation of VLPVPQK reversed the high glucose and fat-induced depression of AKR1B10. Overall, VLPVPQK could alleviate the metabolic disorder of hepatocytes by elevating the glucose uptake and eliminating the ROS, while the HKDC1 and AKR1B10 genes might be the potential target genes and play important roles in the process.

Differential Activation of NRF2 Signaling Pathway in Renal-Cell Carcinoma Caki Cell Lines

Renal-cell carcinoma (RCC) is a heterogeneous disease consisting of several subtypes based on specific genomic profiles and histological and clinical characteristics. The subtype with the highest prevalence is clear-cell RCC (ccRCC), next is papillary RCC (pRCC), and then chromophobe RCC (chRCC). The ccRCC cell lines are further subdivided into prognostic expression-based subtypes ccA or ccB. This heterogeneity necessitates the development, availability, and utilization of cell line models with the correct disease phenotypic characteristics for RCC research. In this study, we focused on characterizing proteomic differences between the Caki-1 and Caki-2 cell lines that are commonly used in ccRCC research. Both cells are primarily defined as human ccRCC cell lines. Caki-1 cell lines are metastatic, harboring wild-type VHL, whereas Caki-2 are considered as the primary ccRCC cell lines expressing wild-type von Hippel–Lindau protein (pVHL). Here, we performed a comprehensive comparative proteomic analysis of Caki-1 and Caki-2 cells using tandem mass-tag reagents together with liquid chromatography mass spectrometry (LC/MS) for the identification and quantitation of proteins in the two cell lines. Differential regulation of a subset of the proteins identified was validated using orthogonal methods including western blot, q-PCR, and immunofluorescence assays. Integrative bioinformatic analysis identifies the activation/inhibition of specific molecular pathways, upstream regulators, and causal networks that are uniquely regulated and associated with the two cell lines and RCC subtypes, and potentially the disease stage. Altogether, we have identified multiple molecular pathways, including NRF2 signaling, which is the most significantly activated pathway in Caki-2 versus Caki-1 cells. Some of the differentially regulated molecules and signaling pathways could serve as potential diagnostic and prognostic biomarkers and therapeutic targets amongst ccRCC subtypes.

Expression of AKRs superfamily and prognostic in human gastric cancer

The human aldo-keto reductase (AKRs) superfamily is involved in the development of various tumors. However, the different expression patterns of AKRs and their prognostic value in gastric cancer (GC) have not been clarified. In this study, we analyzed the gene expression and gene methylation level of AKRs in GC patients and the survival data and immune infiltration based on AKRs expression, using data from different databases. We found that the expression levels of AKR1B10, AKR1C1, AKR1C2, and AKR7A3 in GC tissues were lower and the expression level of AKR6A5 was higher in GC tissues than in normal tissue. These differentially expressed genes (AKR1B10, AKR1C1, AKR1C2, AKR7A3, and AKR6A5) were significantly correlated with the infiltration level. The expression of SPI1 and AKR6A5 in GC was positively correlated. Survival analysis showed that GC levels of AKR6A5 reduced or increased mRNA levels of AKR7A3, and AKR1B10 was expected to have higher overall survival (OS), first progression (FP) survival, and postprogression survival (PPS) rates and a better prognosis. Moreover, the expression of AKR1B1 was found to be correlated with the staging of GC. The methylation of AKR6A5 (KCNAB2) at cg05307871 and cg01907457 was significantly associated with the classification of GC. Meta-analysis and ROC curve analysis show that the expression level of AKR1B1 and the methylation of cg16156182 (KCNAB1), cg11194299 (KCNAB2), cg16132520 (AKR1B1), and cg13801416 (AKR1B1) had a high hazard ratio and a good prognostic value. These data suggest that the expression and methylation of AKR1B1 and AKR6A5 are significantly related to the prognosis.

Identification of AKR1B10 as a key gene in primary biliary cholangitis by integrated bioinformatics analysis and experimental validation

Background: Primary biliary cholangitis (PBC) is a chronic autoimmune liver disease that eventually progresses to cirrhosis and hepatocellular carcinoma (HCC) in the absence of proper treatment. However, Gene expression and molecular mechanisms involved in the pathogenesis of PBC have not been completely elucidated. Methods: Microarray expression profiling dataset GSE61260 was downloaded from the Gene Expression Omnibus (GEO) database. Data were normalized to screen differentially expressed genes (DEGs) using the limma package in R. Moreover, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) enrichment analyses were performed. A protein-protein interaction (PPI) network was constructed to identify hub genes and an integrative regulatory network of transcriptional factor-DEG-microRNA was established. Gene Set Enrichment Analysis (GSEA) was used to analyze differences in biological states for groups with different expressions of aldo-keto reductase family 1 member B10 (AKR1B10). Immunohistochemistry (IHC) analysis was performed to validate the expression of hepatic AKR1B10 in patients with PBC. The association of hepatic AKR1B10 levels with clinical parameters was evaluated using one-way analysis of variance (ANOVA) and Pearson's correlation analysis. Results: This study identified 22 upregulated and 12 downregulated DEGs between patients with PBC and healthy controls. GO and KEGG analysis revealed that DEGs were mainly enriched in immune reactions. AKR1B10 was identified as a key gene and was further analyzed by screening out hub genes from the PPI network. GSEA analysis indicated that high expression of AKR1B10 might promote PBC to develop into HCC. Immunohistochemistry results verified the increased expression of hepatic AKR1B10 in patients with PBC and demonstrated its positive correlation with the severity of PBC. Conclusion: AKR1B10 was identified as a hub gene in PBC by integrated bioinformatics analysis and clinical validation. The increase of AKR1B10 expression in patients with PBC was associated with disease severity and might promote the progression of PBC to HCC.

Gene Regulatory Network-Classifier: Gene Regulatory Network-Based Classifier and Its Applications to Gastric Cancer Drug (5-Fluorouracil) Marker Identification

The complex mechanisms of diseases involve the disturbance of the molecular network, rather than disorder in a single gene, implying that single gene-based analysis is insufficient to understand these mechanisms. Gene regulatory networks (GRNs) have attracted a lot of interest and various approaches have been developed for their statistical inference and gene network-based analysis. Although various computational methods have been developed, relatively little attention has been paid to incorporation of biological knowledge into the computational approaches. Furthermore, existing studies on network-based analysis perform prediction/classification of status of cell lines based on preconstructed GRNs, implying that we cannot extract prediction/classification-specific gene networks, leading to difficulty in interpretation of biological mechanisms and marker identification related to the status of cancer cell lines. We developed a novel strategy to build a GRN-based classifier, called a GRN-classifier. The proposed GRN-classifier estimates GRNs and classifies cell lines simultaneously, where the gene network is estimated to minimize error in gene network estimation and the negative log-likelihood for classifying cell lines. Thus, we can identify biological status-specific gene regulatory systems, enabling us to achieve biologically reliable interpretation of the classification. We also propose an algorithm to implement the GRN-classifier based on coordinate descent update. Monte Carlo simulations were conducted to examine performance of the GRN-classifier. Results: Our strategy provides effective results in feature selection in the classification model and edge selection in gene network estimation. The GRN-classifier also shows outstanding classification accuracy. We apply the GRN-classifier to classify cancer cell lines into anticancer drug-related status, that is, 5-fluorouracil (5-FU)-sensitive/resistant and 5-FU target/nontarget cancer cell lines. We then identified 5-FU markers based on 5-FU-related status classification-specific gene networks. The mechanisms of the identified markers were verified through literature survey. Our results suggest that the molecular interplay between MYOF and AHNAK2 may play a crucial role in drug resistance and can provide information on the chemotherapy efficiency of 5-FU. It is also suggested that suppression of the identified 5-FU markers, including MYOF/AHNAK2 and AKR1C1/AKR1C3 may improve 5-FU resistance of cancer cell lines.

Novel aldo-keto reductase AKR2E9 regulates aldehyde content in the midgut and antennae of the silkworm (Bombyx mori)

We studied the effects of green leaf volatiles (including reactive aldehydes) emitted by plants on insects that feed on these plants. The silkworm (Bombyx mori) is a model lepidopteran that eats mulberry leaves. Defense-related enzymes in silkworms can be targeted for developing new pest control methods. The aldo-keto reductase (AKR) superfamily catalyzes aldehyde reduction by converting a carbonyl group into an alcohol group. Here, we characterized a novel silkworm AKR, designated as AKR2E9. Recombinant AKR2E9 was overexpressed in Escherichia coli. The recombinant protein was used, along with nicotinamide adenine dinucleotide phosphate as a coenzyme, to reduce aldehydes present in mulberry (Morus alba) leaves. The catalytic efficiency of AKR2E9 toward various aldehyde substrates and its inhibitor sensitivity was lower than those of AKR2E8. High expression levels of akr2e9 messenger RNA (mRNA) were detected in the midgut and antennae of silkworms. In the antennae of adult silkworms, akr2e9 mRNA was more abundant than akr2e8 mRNA. The catalytic efficiency of AKR2E9 was low because of steric hindrance, due to which its active site is blocked. High expression levels of AKR2E9 in the midgut and antennae suggest that it may regulate the detoxification of toxic aldehydes in silkworms.

METTL3 promotes glycolysis and cholangiocarcinoma progression by mediating the m6A modification of AKR1B10

OBJECTIVE

N6-methyladenosine (m6A) RNA methylation is involved in governing the mechanism of tumor progression. We aimed to excavate the biological role and mechanism of the m6A methyltransferase METTL3 in cholangiocarcinoma (CCA).

METHODS

METTL3 expression was determined by database and tissue microarray analyses. The role of METTL3 in CCA was explored by loss- and gain-of-function experiments. The m6A target of METTL3 was detected by RNA sequencing. The role of AKR1B10 in CCA was explored, and the association between METTL3 and AKR1B10 was confirmed by rescue experiments.

RESULT

METTL3 expression was upregulated in CCA tissue, and higher METTL3 expression was implicated in poor prognoses in CCA patients. Overexpression of METTL3 facilitated proliferation, migration, invasion, glucose uptake, and lactate production in CCA cells, whereas knockdown of METTL3 had the opposite effects. We further found that METTL3 deficiency inhibited CCA tumor growth in vivo. RNA sequencing and MeRIP-qPCR confirmed that METTL3 enhanced AKR1B10 expression and m6A modification levels. Furthermore, METTL3 directly binds with AKR1B10 at an m6A modification site. A CCA tissue microarray showed that AKR1B10 expression was upregulated in CCA tissue and that silencing AKR1B10 suppressed the malignant phenotype mentioned above in CCA. Notably, knockdown of AKR1B10 rescued the tumor-promoting effects induced by METTL3 overexpression.

CONCLUSION

Elevated METTL3 expression promotes tumor growth and glycolysis in CCA through m6A modification of AKR1B10, indicating that METTL3 is a potential target for blocking glycolysis for application in CCA therapy.

In-silico Investigations of quinine and quinidine as potential Inhibitors of AKR1B1 and AKR1B10: Functional and structural characterization

The aberrant expression of aldo keto reductases (AKR1B1 & AKR1B10) has been extensively studied in different types of cancer especially the colon cancer but a very few studies have yet been reported regarding the discovery of inhibitors for the treatment of colon cancer by targeting these isozymes. Therefore, there is a need of selective inhibitors of both targets for the eradication of colon cancer. Currently, the study is focused on the exploration of two quinolone compounds i.e., (S)-(6-Methoxyquinolin-4-yl)[(1S,2R,4S,5R)-5-vinylquinuclidin-2-yl]methanol (Quinidine) and (R)-(6-Methoxyquinolin-4-yl)[(1S,2S,4S,5R)-5-vinylquinuclidin-2-yl]methanol (Quinine) as the potential inhibitors of AKR1B1 and AKR1B10 via detailed in-silico approach. The structural properties including vibrational frequencies, dipole moment, polarizability and the optimization energies were estimated using density functional theory (DFT) calculations; where both compounds were found chemically reactive. After that, the optimized structures were used for the molecular docking studies and here quinidine was found more selective towards AKR1B1 and quinine exhibited maximum inhibition of AKR1B10. The results of molecular docking studies were validated by molecular dynamics simulations which provided the deep insight of stability of protein ligand complex. At the end, the ADMET properties were determined to demonstrate the druglikeness properties of both selected compounds. These findings suggested further exploration of both compounds at molecular level using different in-vivo and in-vitro approaches that will lead to the designing of potential inhibitor of AKR1B1/AKR1B10 for curing colon cancer and related malignancies.

LncRNA 1700020I14Rik promotes AKR1B10 expression and activates Erk pathway to induce hepatocyte damage in alcoholic hepatitis

Alcoholic hepatitis (AH), a kind of alcoholic liver disease, shows poor prognosis. Long noncoding RNAs (lncRNAs) exert critical role in liver diseases. Here, we intended to investigate the possible molecular mechanism that 1700020I14Rik-based regulation of microRNA (miR)-137/Aldo-keto reductase family 1 member B10 (AKR1B10) affecting the inflammatory response and hepatocyte damage in AH. AH-related genes and the down-stream regulatory pathway were screnned by bioinformatics. Mouse normal hepatocyte cell line AML12 was selected to construct an ethanol-induced hepatocyte injury model for in vitro mechanistic validation, while we also established an AH mouse model using the ethanol with gradually increased concentration of 2–4% (v/v) for in vivo study. Specific role of 1700020I14Rik/miR-137/AKR1B10 in AML12 cell viability, proliferation and apoptotic capacity as well as inflammation and liver damage in mice were analyzed following ectopic and depletion approaches. We found elevated AKR1B10 and 1700020I14Rik but reduced miR-137 in AH. 1700020I14Rik was able to elevated miR-137-mediated AKR1B10. In vitro cell experiments and in vivo animal experiments validated that 1700020I14Rik reduced ethanol-induced hepatocyte damage and inflammation in AH mice through regulation of miR-137–mediated AKR1B10/Erk axis. The current study underlied that 1700020I14Rik could activate AKR1B10/Erk signaling through inhibition of miR-137, thereby promoting the hepatocyte damage in AH mice.

Moving toward a new horizon for the aldose reductase inhibitor epalrestat to treat drug-resistant cancer

Epalrestat (EPA) is a potent inhibitor of aldose reductases AKR1B1 and AKR1B10, used for decades in Japan for the treatment of diabetic peripheral neuropathy. This orally-active, brain-permeable small molecule, with a relatively rare and essential 2-thioxo-4-thiazolidinone motif, functions as a regulator intracellular carbonyl species. The repurposing of EPA for the treatment of pediatric rare diseases, brain disorders and cancer has been proposed. A detailed analysis of the mechanism of action, and the benefit of EPA to combat advanced malignancies is offered here. EPA has revealed marked anticancer activities, alone and in combination with cytotoxic chemotherapy and targeted therapeutics, in experimental models of liver, colon, and breast cancers. Through inhibition of AKR1B1 and/or AKR1B10 and blockade of the epithelial-mesenchymal transition, EPA largely enhances the sensitivity of cancer cells to drugs like doxorubicin and sorafenib. EPA has revealed a major anticancer effect in an experimental model of basal-like breast cancer and clinical trials have been developed in patients with triple-negative breast cancer. The repurposing of the drug to treat chemo-resistant solid tumors seems promising, but more studies are needed to define the best trajectory for the positioning of EPA in oncology.

Porcine aldo-keto reductase 1C subfamily members AKR1C1 and AKR1C4: Substrate specificity, inhibitor sensitivity and activators

Most members of the aldo-keto reductase (AKR) 1 C subfamily are hydroxysteroid dehydrogenases (HSDs). Similarly to humans, four genes for AKR1C proteins (AKR1C1-AKR1C4) have been identified in the pig, which is a suitable species for biomedical research model of human diseases and optimal organ donor for xenotransplantation. Previous study suggested that, among the porcine AKR1Cs, AKR1C1 and AKR1C4 play important roles in steroid hormone metabolism in the reproductive tissues; however, their biological functions are still unknown. Herein, we report the biochemical properties of the two recombinant enzymes. Kinetic and product analyses of steroid specificity indicated that AKR1C1 is a multi-specific reductase, which acts as 3α-HSD for 3-keto-5β-dihydro-C₁₉/C₂₁-steroids, 3β-HSD for 3-keto-5α-dihydro-C₁₉-steroids including androstenone, 17β-HSD for 17-keto-C₁₉-steroids including estrone, and 20α-HSD for progesterone, showing K_m values of 0.5-11 µM. By contrast, AKR1C4 exhibited only 3α-HSD activity for 3-keto groups of 5α/β-dihydro-C₁₉-steroids, 5β-dihydro-C₂₁-steroids and bile acids (K_m: 1.0-1.9 µM). AKR1C1 and AKR1C4 also showed broad substrate specificity for nonsteroidal carbonyl compounds including endogenous 4-oxo-2-nonenal, 4-hydroxy-nonenal, acrolein, isocaproaldehyde, farnesal, isatin and methylglyoxal, of which 4-oxo-2-nonenal was reduced with the lowest K_m value of 0.9 µM. Moreover, AKR1C1 had the characteristic of reducing aliphatic ketones and all-trans-retinal. The enzymes were inhibited by flavonoids, synthetic estrogens, nonsteroidal anti-inflammatory drugs, triterpenoids and phenolphthalein, whereas only AKR1C4 was activated by bromosulfophthalein. These results suggest that AKR1C1 and AKR1C4 function as 3α/3β/17β/20α-HSD and 3α-HSD, respectively, in metabolism of steroid hormones and a sex pheromone androstenone, both of which also play roles in metabolism of nonsteroidal carbonyl compounds.

Discovery of Phenylcarbamoylazinane-1,2,4-Triazole Amides Derivatives as the Potential Inhibitors of Aldo-Keto Reductases (AKR1B1 & AKRB10): Potential Lead Molecules for Treatment of Colon Cancer

Both members of the aldo-keto reductases (AKRs) family, AKR1B1 and AKR1B10, are over-expressed in various type of cancer, making them potential targets for inflammation-mediated cancers such as colon, lung, breast, and prostate cancers. This is the first comprehensive study which focused on the identification of phenylcarbamoylazinane-1, 2,4-triazole amides (7a−o) as the inhibitors of aldo-keto reductases (AKR1B1, AKR1B10) via detailed computational analysis. Firstly, the stability and reactivity of compounds were determined by using the Guassian09 programme in which the density functional theory (DFT) calculations were performed by using the B3LYP/SVP level. Among all the derivatives, the 7d, 7e, 7f, 7h, 7j, 7k, and 7m were found chemically reactive. Then the binding interactions of the optimized compounds within the active pocket of the selected targets were carried out by using molecular docking software: AutoDock tools and Molecular operation environment (MOE) software, and during analysis, the Autodock (academic software) results were found to be reproducible, suggesting this software is best over the MOE (commercial software). The results were found in correlation with the DFT results, suggesting 7d as the best inhibitor of AKR1B1 with the energy value of −49.40 kJ/mol and 7f as the best inhibitor of AKR1B10 with the energy value of −52.84 kJ/mol. The other potent compounds also showed comparable binding energies. The best inhibitors of both targets were validated by the molecular dynamics simulation studies where the root mean square value of <2 along with the other physicochemical properties, hydrogen bond interactions, and binding energies were observed. Furthermore, the anticancer potential of the potent compounds was confirmed by cell viability (MTT) assay. The studied compounds fall into the category of drug-like properties and also supported by physicochemical and pharmacological ADMET properties. It can be suggested that the further synthesis of derivatives of 7d and 7f may lead to the potential drug-like molecules for the treatment of colon cancer associated with the aberrant expression of either AKR1B1 or AKR1B10 and other associated malignancies.

Identification of Energy Metabolism-Related Gene Signatures From scRNA-Seq Data to Predict the Prognosis of Liver Cancer Patients

The increasingly common usage of single-cell sequencing in cancer research enables analysis of tumor development mechanisms from a wider range of perspectives. Metabolic disorders are closely associated with liver cancer development. In recent years, liver cancer has been evaluated from different perspectives and classified into different subtypes to improve targeted treatment strategies. Here, we performed an analysis of liver cancer from the perspective of energy metabolism based on single-cell sequencing data. Single-cell and bulk sequencing data of liver cancer patients were obtained from GEO and TCGA/ICGC databases, respectively. Using the Seurat R package and protocols such as consensus clustering analysis, genes associated with energy metabolism in liver cancer were identified and validated. An energy metabolism-related score (EM score) was established based on five identified genes. Finally, the sensitivity of patients in different scoring groups to different chemotherapeutic agents and immune checkpoint inhibitors was analyzed. Tumor cells from liver cancer patients were found to divide into nine clusters, with cluster 4 having the highest energy metabolism score. Based on the marker genes of this cluster and TCGA database data, the five most stable key genes (ADH4, AKR1B10, CEBPZOS, ENO1, and FOXN2) were identified as energy metabolism-related genes in liver cancer. In addition, drug sensitivity analysis showed that patients in the low EM score group were more sensitive to immune checkpoint inhibitors and chemotherapeutic agents AICAR, metformin, and methotrexate.

The Potent Phytoestrogen 8-Prenylnaringenin: A Friend or a Foe?

8-prenylnaringenin (8-PN) is a prenylated flavonoid, occurring, in particular, in hop, but also in other plants. It has proven to be one of the most potent phytoestrogens in vitro known to date, and in the past 20 years, research has unveiled new effects triggered by it in biological systems. These findings have aroused the hopes, expectations, and enthusiasm of a “wonder-drug” for a host of human diseases. However, the majority of 8-PN effects require such high concentrations that they cannot be reached by normal dietary exposure, only pharmacologically; thus, adverse impacts may also emerge. Here, we provide a comprehensive and up-to-date review on this fascinating compound, with special reference to the range of beneficial and untoward health consequences that may ensue from exposure to it.

AKR1B10, One of the Triggers of Cytokine Storm in SARS-CoV2 Severe Acute Respiratory Syndrome

Preventing the cytokine storm observed in COVID-19 is a crucial goal for reducing the occurrence of severe acute respiratory failure and improving outcomes. Here, we identify Aldo-Keto Reductase 1B10 (AKR1B10) as a key enzyme involved in the expression of pro-inflammatory cytokines. The analysis of transcriptomic data from lung samples of patients who died from COVID-19 demonstrates an increased expression of the gene encoding AKR1B10. Measurements of the AKR1B10 protein in sera from hospitalised COVID-19 patients suggests a significant link between AKR1B10 levels and the severity of the disease. In macrophages and lung cells, the over-expression of AKR1B10 induces the expression of the pro-inflammatory cytokines Interleukin-6 (IL-6), Interleukin-1β (IL-1β) and Tumor Necrosis Factor a (TNFα), supporting the biological plausibility of an AKR1B10 involvement in the COVID-19-related cytokine storm. When macrophages were stressed by lipopolysaccharides (LPS) exposure and treated by Zopolrestat, an AKR1B10 inhibitor, the LPS-induced production of IL-6, IL-1β, and TNFα is significantly reduced, reinforcing the hypothesis that the pro-inflammatory expression of cytokines is AKR1B10-dependant. Finally, we also show that AKR1B10 can be secreted and transferred via extracellular vesicles between different cell types, suggesting that this protein may also contribute to the multi-organ systemic impact of COVID-19. These experiments highlight a relationship between AKR1B10 production and severe forms of COVID-19. Our data indicate that AKR1B10 participates in the activation of cytokines production and suggest that modulation of AKR1B10 activity might be an actionable pharmacological target in COVID-19 management.

Pirin, an Nrf2-Regulated Protein, Is Overexpressed in Human Colorectal Tumors

The evolutionary conserved non-heme Fe-containing protein pirin has been implicated as an important factor in cell proliferation, migration, invasion, and tumour progression of melanoma, breast, lung, cervical, prostate, and oral cancers. Here we found that pirin is overexpressed in human colorectal cancer in comparison with matched normal tissue. The overexpression of pirin correlates with activation of transcription factor nuclear factor erythroid 2 p45-related factor 2 (Nrf2) and increased expression of the classical Nrf2 target NAD(P)H:quinone oxidoreductase 1 (NQO1), but interestingly and unexpectedly, not with expression of the aldo-keto reductase (AKR) family members AKR1B10 and AKR1C1, which are considered to be the most overexpressed genes in response to Nrf2 activation in humans. Using pharmacologic and genetic approaches to either downregulate or upregulate Nrf2, we show that pirin is regulated by Nrf2 in human and mouse cells and in the mouse colon in vivo. The small molecule pirin inhibitor TPhA decreased the viability of human colorectal cancer (DLD1) cells, but this decrease was independent of the levels of pirin. Our study demonstrates the Nrf2-dependent regulation of pirin and encourages the pursuit for specific pirin inhibitors.

MicroRNA-383: A tumor suppressor miRNA in human cancer

Downregulated expression of anti-tumor miR-383 has been found in many kinds of cancer. MiR-383 family members can directly target the 3'-untranslated region (3'-UTR) of the mRNA of some pro-tumor genes to attenuate several cancer-related processes, including cell proliferation, invasion, migration, angiogenesis, immunosuppression, epithelial-mesenchymal transition, glycolysis, chemoresistance, and the development of cancer stem cells, whilst promoting apoptosis. Functionally, miR-383 operates as a tumor inhibitor miRNA in many types of cancer, including breast cancer, hepatocellular carcinoma, gastric cancer, pancreatic cancer, colorectal cancer, esophageal cancer, lung cancer, head and neck cancer, glioma, medulloblastoma, melanoma, prostate cancer, cervical cancer, oral squamous cell carcinoma, thyroid cancer, and B-cell lymphoma. Both pro-tumor and anti-tumor effects have been attributed to miR-383 in ovarian cancer. However, only the pro-tumor effects of miR-383 were reported in cholangiocarcinoma. The restoration of miR-383 expression could be considered a possible treatment for cancer. This review discusses the anti-tumor effects of miR-383 in human cancers, emphasizing their downstream target genes and potential treatment approaches.

Role of AKR1B10 and AKR1B8 in the pathogenesis of non-alcoholic steatohepatitis (NASH) in mouse

Non-alcoholic steatohepatitis (NASH) is a clinically important spectrum of non-alcoholic fatty liver disease (NAFLD) in humans. NASH is a stage of NAFLD progression wherein liver steatosis accompanies inflammation and pro-fibrotic events. Presently, there are no approved drugs for NASH, which has become a leading cause of liver transplant worldwide. To discover novel drug targets for NASH, we analyzed a human transcriptomic NASH dataset and found Aldo-keto reductase family 1 member B10 (AKR1B10) as a significantly upregulated gene in livers of human NASH patients. Similarly murine Akr1b10 and Aldo-keto reductase family 1 member B8 (Akr1b8) gene, which is a murine ortholog of human AKR1B10, were also found to be upregulated in a mouse model of diet-induced NASH. Furthermore, pharmacological inhibitors of AKR1B10 significantly reduced the pathological features of NASH such as steatosis, inflammation and fibrosis in mouse. In addition, genetic silencing of both mouse Akr1b10 and Akr1b8 significantly reduced the expression of proinflammatory cytokines from hepatocytes. These results thus underscore the involvement of murine AKR1B10 and AKR1B8 in the pathogenesis of murine NASH and raise an intriguing possibility of a similar role of AKR1B10 in human NASH.

Perspective on the Structural Basis for Human Aldo-Keto Reductase 1B10 Inhibition

Human aldo-keto reductase 1B10 (AKR1B10) is overexpressed in many cancer types and is involved in chemoresistance. This makes AKR1B10 to be an interesting drug target and thus many enzyme inhibitors have been investigated. High-resolution crystallographic structures of AKR1B10 with various reversible inhibitors were deeply analyzed and compared to those of analogous complexes with aldose reductase (AR). In both enzymes, the active site included an anion-binding pocket and, in some cases, inhibitor binding caused the opening of a transient specificity pocket. Different structural conformers were revealed upon inhibitor binding, emphasizing the importance of the highly variable loops, which participate in the transient opening of additional binding subpockets. Two key differences between AKR1B10 and AR were observed regarding the role of external loops in inhibitor binding. The first corresponded to the alternative conformation of Trp112 (Trp111 in AR). The second difference dealt with loop A mobility, which defined a larger and more loosely packed subpocket in AKR1B10. From this analysis, the general features that a selective AKR1B10 inhibitor should comply with are the following: an anchoring moiety to the anion-binding pocket, keeping Trp112 in its native conformation (AKR1B10-like), and not opening the specificity pocket in AR.

AKR1B10 inhibits the proliferation and migration of gastric cancer via regulating epithelial-mesenchymal transition

Gastric cancer (GC) is a common malignancy around the world with a poor prognosis. Aldo-keto reductase family 1 member B10 (AKR1B10) is indispensable to cancer development and progression, which has served as a diagnostic biomarker for tumors. In our study, we demonstrated that the expression of AKR1B10 in GC tissues was significantly lower compared with normal gastric tissues. Subgroup analysis showed that, according to the clinic-pathological factors, the effect of the AKR1B10 expression level on the prognosis of GC patients was significantly different. Moreover, reduced expression of AKR1B10 promoted the ability of GC cells in proliferation and migration. Furthermore, increased AKR1B10 levels resulted in the opposite trend in vitro. Moreover, AKR1B10 was correlated with epithelial-mesenchymal transition (EMT) in a significant way. In vivo experiment, knockdown of AKR1B10 promoted the growth of tumor, increased Vimentin, and E-cadherin significantly. In summary, AKR1B10 is considered as a tumor suppressor in GC and is a promising therapeutic target.