Involvement of Apelin/APJ Axis in Thrombogenesis in Valve Heart Disease Patients with Atrial Fibrillation.

The mechanism underlying thrombosis in atrial fibrillation (AF) is not yet clearly understood. The apelin/APJ axis parallel and counter-regulate with the angiotensin system. The present study hypothesizes that apelin/APJ axis exert its anti-thrombus effect in normal left atrial tissue and is disrupted by up-regulated renin-angiotensin-aldosterone system (RAAS) signaling during AF. The specimens of left atrial appendages collected from patients with rheumatic mitral stenosis who underwent valve replacement were divided into 3 groups: sinus rhythm, AF+/thrombus-, and AF+/thrombus+. The amounts of angiotensin II receptor subtype 1 (AT1), apelin/APJ and its downstream plasminogen activator inhibitor-1 (PAI-1) were detected by western blot. The expression of apelin/APJ was significantly decreased in the AF+/thrombus+ group compared with the sinus rhythm and AF+/thrombus- groups. Meanwhile the expressions of AT1 and PAI-1 were highest in the AF+/thrombus+ group compared to the other two groups. Taken together, the present study reveals apelin/APJ axis might be correlated with thrombosis in patients with AF mediated by PAI-1.

Advanced Glycation Endproducts Impair Endothelial Progenitor Cell Migration and Homing via Syndecan 4 Shedding.

Endothelial progenitor cells (EPCs) are a subtype of bone marrow-derived progenitor cells. Stromal cell-derived factor 1 (SDF-1)-mediated EPC mobilization from bone marrow to areas of ischemia plays an important role in angiogenesis. Previous studies have reported that advanced glycation endproducts (AGEs), which are important mediators of diabetes-related vascular pathology, may impair EPC migration and homing, but the mechanism is unclear. Syndecan-4 (synd4) is a ubiquitous heparan sulfate proteoglycan receptor on the cell surface, involved in SDF-1-dependent cell migration. The extracellular domain of synd4 (ext-synd4) is shed in the context of acute inflammation, but the shedding of ext-synd4 in response to AGEs is undefined. Here we investigated changes in ext-synd4 on EPCs in response to AGEs, focusing on the influence of impaired synd4 signaling on EPC migration and homing. We found decreased full length and increased residue of synd4 in cells incubated with AGEs, with concomitant increase in the soluble fragment of ext-synd4 in the cell medium. EPCs from patients with type 2 diabetes expressed less ext-synd4 as assessed by Western blotting. Flow cytometry analysis showed less ext-synd4 on circulating CD34+ peripheral blood mononuclear cells, of which EPCs form a subgroup. We then explored the role of synd4 in EPC migration and homing. Impaired migration of synd4-deficient EPCs was observed by a 2D-chemotaxis slide. Furthermore, poor homing of synd4-/- EPCs was observed in a mouse model of lower limb ischemia. This study demonstrates that the shedding of synd4 from EPCs plays a key role in AGE-mediated dysfunction of EPC migration and homing. Stem Cells 2017;35:522-531.

Syndecan-4 Signaling Is Required for Exercise-Induced Cardiac Hypertrophy.

Cardiac hypertrophy can be broadly classified as either physiological or pathological. Physiological stimuli such as exercise cause adaptive cardiac hypertrophy and normal heart function. Pathological stimuli including hypertension and aortic valvular stenosis cause maladaptive cardiac remodeling and ultimately heart failure. Syndecan-4 (synd4) is a transmembrane proteoglycan identified as being involved in cardiac adaptation after injury, but whether it takes part in physiological cardiac hypertrophy is unclear. We observed upregulation of synd4 in exercise-induced hypertrophic myocardium. To evaluate the role of synd4 in the physiological form of cardiac hypertrophy, mice lacking synd4 (synd4-/-) were exercised by swimming for 4 wks. Ultrasonic cardiogram (UCG) and histological analysis revealed that swimming induced the hypertrophic phenotype but was blunted in synd4-/- compared with wild-type (WT) mice. The swimming-induced activation of Akt, a key molecule in physiological hypertrophy was also more decreased than in WT controls. In cultured cardiomyocytes, synd4 overexpression could induce cell enlargement, protein synthesis and distinct physiological molecular alternation. Akt activation also was observed in synd4-overexpressed cardiomyocytes. Furthermore, inhibition of protein kinase C (PKC) prevented the synd4-induced hypertrophic phenotype and Akt phosphorylation. This study identified an essential role of synd4 in mediation of physiological cardiac hypertrophy.

Differential gene expression in Staphylococcus aureus exposed to Orange II and Sudan III azo dyes.

We previously demonstrated the effects of azo dyes and their reduction metabolites on bacterial cell growth and cell viability. In this report, the effects of Orange II and Sudan III on gene expression profiling in Staphylococcus aureus ATCC BAA 1556 were analyzed using microarray and quantitative RT-PCR technology. Upon exposure to 6 µg/ml Orange II for 18 h, 21 genes were found to be differently expressed. Among them, 8 and 13 genes were up- and down-regulated, respectively. Most proteins encoded by these differentially expressed genes involve stress response caused by drug metabolism, oxidation, and alkaline shock indicating that S. aureus could adapt to Orange II exposure through a balance between up and down regulated gene expression. Whereas, after exposure to 6 µg/ml Sudan III for 18 h, 57 genes were differentially expressed. In which, 51 genes were up-regulated and 6 were down-regulated. Most proteins encoded by these differentially expressed genes involve in cell wall/membrane biogenesis and biosynthesis, nutrient uptake, transport and metabolite, and stress response, suggesting that Sudan III damages the bacterial cell wall or/and membrane due to binding of the dye. Further analysis indicated that all differentially expressed genes encoded membrane proteins were up-regulated and most of them serve as transporters. The result suggested that these genes might contribute to survival, persistence and growth in the presence of Sudan III. Only one gene msrA, which plays an important role in oxidative stress resistance, was found to be down-regulated after exposure to both Orange II and Sudan III. The present results suggested that both these two azo dyes can cause stress in S. aureus and the response of the bacterium to the stress is mainly related to characteristics of the azo dyes.

A comparison of conventional methods for the quantification of bacterial cells after exposure to metal oxide nanoparticles.

BACKGROUND: Due to potential interference of nanoparticles on bacterial quantification, there is a challenge to develop a fast, accurate and reproducible method for bacterial quantification. Currently various bacterial quantification methods are used by researchers performing nanoparticles study, but there has been no efficacy evaluation of these methods. Here we study interference of nanoparticles on three most commonly used conventional bacterial quantification methods, including colony counting to determine the colony-forming units (CFU), spectrophotometer method of optical density (OD) measurement, and flow cytometry (FCM). RESULTS: Three oxide nanoparticles including ZnO, TiO2, and SiO2 and four bacterial species including Salmonella enterica serovar Newport, Staphylococcus epidermidis, Enterococcus faecalis, and Escherichia coli were included in the test. Results showed that there is no apparent interference of the oxide nanoparticles on quantifications of all four bacterial species by FCM measurement; CFU counting is time consuming, less accurate and not suitable for automation; and the spectrophotometer method using OD measurement was the most unreliable method to quantify and detect the bacteria in the presence of the nanoparticles. CONCLUSION: In summary, FCM measurement proved to be the best method, which is suitable for rapid, accurate and automatic detection of bacteria in the presence of the nanoparticles.

[Effect of anxin granules combined with tirofiba on patients with acute myocardial infarction after elective percutaneous coronary intervention].

To investigate the influence of Anxin granules combined with tirofiban on acute myocardial infarction (AMI) Patients after elective percutaneous coronary intervention (PCI). One hundred and twenty AMI patients were randomly divided into treatment group and control group. The patients in the two groups were all given Tirofiban 30mins before PCI . The treatment group was added Anxin granules 30 mins before and after PCI. Tissue factor (TF) and von willebrand factor (vWF) were tested at 6 hours after operation. Syndromatology alteration of traditional Chinese medicine (TCM) and bleeding complications were observed at 4 weeks after operation. Both TF and vWF at 6 hours after operation of the treatment group was lower than the control group significantly (P < 0.01), while the condition of myocardial ischemia at 90 mins after operation of the treatment group was better than control group with significance. The syndromatology alteration of TCM especially spontaneous perspiration and hypodynamia of the treatment group were improved significantly compared to control group 4 weeks after operation. All patients in both groups had no bleeding complications and thrombopenia. The study suggests that Anxin granules combined with tirofiba can improve the clinical efficacy and the endothelial function of AMI patients after PCI with no increase in bleeding events.

Five-Year Outcomes of Bioresorbable Stent Therapy for Coronary Heart Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: The efficacy of bioresorbable vascular scaffolds (BVS) compared to metallic stents for the treatment of coronary heart disease remains controversial. The analysis of clinical outcomes at five years following the initial treatment has yet to be reviewed. This study sought to assess the five-year outcomes in randomized controlled trials of BVS in the treatment of coronary heart disease using a systematic review and meta-analysis. Methods: A systematic database search was conducted from their inception to June 30th, 2023 using various Medical Subject Headings (MeSH) terms including: "Coronary Disease", "Bioresorbable stent", "Randomized controlled trials". Results: After a rigorous selection process, a total of five high-quality articles were finally included in this study. Each trial demonstrated a low risk of bias. After 5 years, bioresorbable stents showed outcomes similar to conventional metal stents in terms of cardiac mortality. However, they were inferior in terms of lesion revascularization rates, in-stent thrombosis rates, target lesion failure, target vessel failure, and myocardial infarction. Conclusions: While bioresorbable stents are comparable to metallic stents in terms of cardiac mortality rates, they exhibit significant drawbacks that warrant clinical consideration.

Causal relationship between the gut microbiota, immune cells, and coronary heart disease: a mediated Mendelian randomization analysis.

Background: Recent studies have shown that the gut microbiota (GM), immune cells, and coronary heart disease (CHD) are closely related, but the causal nature of these relationships is largely unknown. This study aimed to investigate this causal relationship and reveal the effect of GM and immune cells on the risk of developing CHD using mediated Mendelian randomization (MR) analysis. Methods: First, we searched for data related to GM, immune cells, and CHD through published genome-wide association studies (GWAS). We filtered the single nucleotide polymorphisms (SNPs) associated with GM and immune cells and then performed the first MR analysis to identify disease-associated intestinal bacteria and disease-associated immune cells. Subsequently, three MR analyses were conducted: from disease-associated GM to disease-associated immune cells, from disease-associated immune cells to CHD, and from disease-associated GM to CHD. Each MR analysis was conducted using inverse variance weighting (IVW), MR-Egger regression, weighted median, weighted models, and simple models. Results: A total of six GM and 25 immune cells were found to be associated with CHD. In the MR analysis using the inverse variance weighting (IVW) method, g__Desulfovibrio.s__Desulfovibrio_piger was associated with EM DN (CD4-CD8-) %T cells (P < 0.05 and OR > 1), EM DN (CD4-CD8-) %T cells was associated with CHD (P < 0.05 and OR < 1), and g__Desulfovibrio.s__Desulfovibrio_piger was associated with CHD (P < 0.05 and OR < 1). Conclusion: An increase in the abundance of g__Desulfovibrio.s__Desulfovibrio_piger leads to an increase in the amount of EM DN (CD4-CD8-) %T cells, and an increase in the amount of EM DN (CD4-CD8-) %T cells reduces the risk of developing CHD. Our study provides some references for reducing the incidence of CHD by regulating GM and immune cells.

Nanomaterials Regulate Bacterial Quorum Sensing: Applications, Mechanisms, and Optimization Strategies.

Anti-virulence therapy that interferes with bacterial communication, known as "quorum sensing (QS)", is a promising strategy for circumventing bacterial resistance. Using nanomaterials to regulate bacterial QS in anti-virulence therapy has attracted much attention, which is mainly attributed to unique physicochemical properties and excellent designability of nanomaterials. However, bacterial QS is a dynamic and multistep process, and there are significant differences in the specific regulatory mechanisms and related influencing factors of nanomaterials in different steps of the QS process. An in-depth understanding of the specific regulatory mechanisms and related influencing factors of nanomaterials in each step can significantly optimize QS regulatory activity and enhance the development of novel nanomaterials with better comprehensive performance. Therefore, this review focuses on the mechanisms by which nanomaterials regulate bacterial QS in the signal supply (including signal synthesis, secretion, and accumulation) and signal transduction cascade (including signal perception and response) processes. Moreover, based on the two key influencing factors (i.e., the nanomaterial itself and the environment), optimization strategies to enhance the QS regulatory activity are comprehensively summarized. Collectively, applying nanomaterials to regulate bacterial QS is a promising strategy for anti-virulence therapy. This review provides reference and inspiration for further research on the anti-virulence application of nanomaterials.

Immune signature and phagocytosis of circulating DC subsets in healthy adults during aging.

Dendritic cells (DC) play a pivotal role in the onset and progression of immunosenescence-associated diseases, serving as a link between innate and adaptive immunity. Thus, there is a need to establish reference ranges for DC subset levels in healthy adults and investigate the potential impact of age on DC subset levels and phagocytic activity. Single-platform multi-color flow cytometry was performed to assess the proportions of circulating conventional type 1 DC (cDC1), conventional type 2 DC (cDC2), and plasmacytoid DC (pDC), as well as the percentages of CD80, CD86, CD83, PD-L1, and CD32 in cDC1, cDC2, and pDC. Reference ranges were established based on age and gender, and the percentage of circulating DC subsets in different age groups was compared. In addition, circulating DC were enriched using a magnetic bead sorting kit and co-cultured with polystyrene (PS) beads, categorized by age groups, followed by the evaluation of PS bead phagocytosis using light microscopy and flow cytometry. The results indicated that the percentages of circulating cDC1, cDC2, and CD32+cDC2 decreased with age (P < 0.05) and revealed age-related impairment in phagocytic percentage of cDC2 (P < 0.05). These findings provide a deeper understanding of the impact of age on the phenotype and phagocytic activity of DC subsets, shedding light on their role and function in immunosenescence.

PI3K/AKT/mTOR and PD­1/CTLA­4/CD28 pathways as key targets of cancer immunotherapy (Review).

T cells play an important role in cancer, and energy metabolism can determine both the proliferation and differentiation of T cells. The inhibition of immune checkpoint molecules programmed cell death protein 1 (PD-1) and cytotoxic T-lymphocyte associated protein 4 (CTLA-4) are a promising cancer treatment. In recent years, research on CD28 has increased. Although numerous reports involve CD28 and its downstream PI3K/AKT/mTOR signaling mechanisms in T cell metabolism, they have not yet been elucidated. A literature search strategy was used for the databases PubMed, Scopus, Web of Science and Cochrane Library to ensure broad coverage of medical and scientific literature, using a combination of keywords including, but not limited to, 'lung cancer' and 'immunotherapy'. Therefore, the present study reviewed the interaction and clinical application of the PD-1/CTLA-4/CD28 and PI3K/AKT/mTOR pathways in T cells, aiming to provide a theoretical basis for immunotherapy in clinical cancer patients.

Effect of perioperative cognitive behavioral interventions on pain, anxiety, and sleep quality in elderly patients after sinus floor elevation and immediate implantation: A randomized controlled trial.

BACKGROUND: Sinus floor elevation and immediate dental implantation are commonly performed to treat dentition defects in elderly patients. Targeted cognitive behavioral interventions (CBI) during the perioperative period can reduce pain and anxiety as well as improve sleep quality. This can lead to improvements in patient cooperation during follow-up treatment and enhance the overall efficacy of the surgery. OBJECTIVE: The study aimed to investigate the impact of a cognitive behavioral intervention method on perioperative pain, anxiety, and sleep quality in elderly patients undergoing sinus floor elevation and immediate dental implantation. METHODS: Forty patients who required the treatment at the Stomatology Clinic in our hospital between December 2018 and December 2022 were enrolled in this randomized controlled trial. The patients were randomly divided into two groups: a control group (n= 20), which received conventional treatment and care during the perioperative period, and an intervention group (n= 20), which received comprehensive behavioral intervention in addition to the conventional treatment and care during the perioperative period. The perioperative anxiety, pain, and sleep quality of the patients in both groups were evaluated. Anxiety was assessed using the Self-Rating Anxiety Scale (SAS), sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI), and pain was measured using the visual analog scale (VAS). RESULTS: No statistically significant differences in SAS and PSQI were observed between the two groups at the initial visit; the values were significantly higher than those measured postoperatively. The SAS scores and PSQI of patients on days 0 and 7 post-surgery in the intervention group were significantly lower than those in the control group (P< 0.05). CONCLUSION: Perioperative cognitive behavioral intervention can effectively improve anxiety, postoperative pain and sleep quality in elderly patients who have undergone sinus floor elevation and immediate dental implantation, thereby reducing the incidence of complications.

The effect of motivational interviewing based on the transtheoretical model on oral cleaning behavior of patients with periodontitis who have undergone implant restoration.

BACKGROUND: Implant-restored patients with periodontitis have a higher risk of developing peri-implantitis, and helping them develop oral cleaning habits is significant. OBJECTIVE: To evaluate the effectiveness of motivational interviewing based on the transtheoretical model on the modification of oral cleaning behaviors of implant-restored patients with periodontitis. METHODS: Patients with periodontitis (n= 70) who would receive dental implant treatment were included. And they were randomly divided into two groups: experimental (n= 35) and control (n= 35). Control patients received routine oral hygiene education, and those in the experimental group received motivational interviewing based on the transtheoretical model. Oral cleaning behavior was compared between the two groups before and after intervention. In addition, periodontal health status was compared on the day of implant restoration and three months later. RESULTS: Compared to the control, the experimental group demonstrated significantly better oral hygiene behavior after intervention (P< 0.05). Three months after implant restoration, significantly better results were obtained by the experimental group in terms of mPLI and mSBI (P< 0.05). CONCLUSION: Motivational interviewing based on the transtheoretical model can effectively improve the oral cleaning behavior and periodontal health of implant-restored patients with periodontitis.

Evaluation of impact of exposure of Sudan azo dyes and their metabolites on human intestinal bacteria.

Sudan azo dyes are banned for food usage in most countries, but they are illegally used to maintain or enhance the color of food products due to low cost, bright staining, and wide availability of the dyes. In this report, we examined the toxic effects of these azo dyes and their potential reduction metabolites on 11 prevalent human intestinal bacterial strains. Among the tested bacteria, cell growth of 2, 3, 5, 5, and 1 strains was inhibited by Sudan I, II, III, IV, and Para Red, respectively. At the tested concentration of 100 µM, Sudan I and II inhibited growth of Clostridium perfringens and Lactobacillus rhamnosus with decrease of growth rates from 14 to 47%. Sudan II also affected growth of Enterococcus faecalis. Growth of Bifidobacterium catenulatum, C. perfringens, E. faecalis, Escherichia coli, and Peptostreptococcus magnus was affected by Sudan III and IV with decrease in growth rates from 11 to 67%. C. perfringens was the only strain in which growth was affected by Para Red with 47 and 26% growth decreases at 6 and 10 h, respectively. 1-Amino-2-naphthol, a common metabolite of the dyes, was capable of inhibiting growth of most of the tested bacteria with inhibition rates from 8 to 46%. However, the other metabolites of the dyes had no effect on growth of the bacterial strains. The dyes and their metabolites had less effect on cell viability than on cell growth of the tested bacterial strains. Clostridium indolis and Clostridium ramosum were the only two strains with about a 10 % decrease in cell viability in the presence of Sudan azo dyes. The present results suggested that Sudan azo dyes and their metabolites potentially affect the human intestinal bacterial ecology by selectively inhibiting some bacterial species, which may have an adverse effect on human health.

Sensitive angle-dependent magnetoelectric coupling in cluster-assembled flexible composites.

Flexible magnetoelectric (ME) device is one of the indispensable elements. However, the complicated fabrication process and low sensitivity hinder the practical applications. Here, flexible NiFe anisotropic magnetoelastic composites were prepared by cluster-supersonic expansion method assistant with polyvinylidene fluoride (PVDF) substrates. The NiFe/PVDF composites possess sensitive angle-resolution ME coupling coefficient at room temperature, and the value can reach 0.66µV deg-1. The strong anisotropic magnetoelasticity phenomenon is reminiscent of the short-range ordered cluster structure. The anisotropic magnetoelastic coefficient can be deduced by temperature- and magnetic field strength-dependent anisotropic magnetoresistance. The magnetic torque results also prove the strong anisotropic magnetoelastic trait. The coupling between piezoelectricity and anisotropic magnetostrictive effect endows great possibilities toward flexible electronic compass. These results shed light on future in non-invasive tracking of vital biological health via wearable electronic devices.

SugE, a new member of the SMR family of transporters, contributes to antimicrobial resistance in Enterobacter cloacae.

We cloned a gene, sugE, from the chromosome of Enterobacter cloacae ATCC 13047. Analysis of the susceptibilities of the sugE-containing strain (Escherichia coli KAM32/pSUGE28) and sugE-deficient E. cloacae (EcΔsugE) showed that SugE confers resistance to cetyltrimethylammonium bromide, cetylpyridinium chloride, tetraphenylphosphonium, benzalkonium chloride, ethidium bromide, and sodium dodecyl sulfate. We also investigated expression of sugE. We confirm here that SugE from E. cloacae is an SMR family transporter as determined by observing its energy-dependent drug efflux activity.

EmmdR, a new member of the MATE family of multidrug transporters, extrudes quinolones from Enterobacter cloacae.

We cloned a gene, ECL_03329, from the chromosome of Enterobacter cloacae ATCC13047, using a drug-hypersensitive Escherichia coli KAM32 cell as the host. We show here that this gene, designated as emmdR, is responsible for multidrug resistance in E. cloacae. E. coli KAM32 host cells containing the cloned emmdR gene (KAM32/pEMMDR28) showed decreased susceptibilities to benzalkonium chloride, norfloxacin, ciprofloxacin, levofloxacin, ethidium bromide, acriflavine, rhodamine6G, and trimethoprim. emmdR-deficient E. cloacae cells (EcΔemmdR) showed increased susceptibilities to several of the antimicrobial agents tested. EmmdR has twelve predicted transmembrane segments and some shared identity with members of the multidrug and toxic compound extrusion (MATE) family of transporters. Study of the antimicrobial agent efflux activities revealed that EmmdR is an H+-drug antiporter but not a Na+ driven efflux pump. These results indicate that EmmdR is responsible for multidrug resistance and pumps out quinolones from E. cloacae.

Effects of Qishen Yiqi Dripping Pills () in Reducing Myocardial Injury and Preserving Microvascular Function in Patients Undergoing Elective Percutaneous Coronary Intervention: A Pilot Randomized Study.

OBJECTIVE: To evaluate the effect of treatment with Qishen Yiqi Dripping Pills (, QSYQ) on myocardial injury and myocardial microvascular function in patients undergoing elective percutaneous coronary intervention (PCI). METHODS: Eighty patients undergoing elective PCI were randomly assigned to QSYQ and control groups. The QSYQ group received QSYQ at a dosage of 0.5 g 3 times daily (3-7 days before PCI and then daily for 1 month) and regular medication, which comprised of aspirin, clopidogrel, statin, ß-blocker, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker in the absence of contradiction. The control group received only the regular medication. The index of microcirculatory resistance (IMR) was measured at maximal hyperemia after PCI. The fractional flow reserve was measured before and after the procedure. Troponin I levels were obtained at baseline and 20-24 h after the procedure. RESULTS: Pre-PCI troponin I levels between the two groups were similar (0.028±0.05 vs. 0.022±0.04 ng/mL, P=0.55). However, post- PCI troponin I levels in the QSYQ group were significantly lower than that in the control group (0.11±0.02 vs. 0.16±0.09 ng/mL, P<0.01). IMR values were significantly lower in the QSYQ group as compared to the control group (16.5±6.1 vs. 31.2±16.0, P<0.01). Multivariate analysis identified QSYQ treatment as the only independent protective factor against IMR >32 (odds ratio=0.29, 95% confidence interval: 0.11-0.74, P=0.01). CONCLUSIONS: The present study demonstrated the benefit of QSYQ in reducing myocardial injury and preserving microvascular function during elective PCI.

Mutation network-based understanding of pleiotropic and epistatic mutational behavior of Enterococcus faecalis FMN-dependent azoreductase.

We previously identified a highly active homodimeric FMN-dependent NADH-preferred azoreductase (AzoA) from Enterococcus faecalis, which cleaves the azo bonds (R-NË­N-R) of diverse azo dyes, and determined its crystal structure. The preliminary network-based mutational analysis suggested that the two residues, Arg-21 and Asn-121, have an apparent mutational potential for fine-tuning of AzoA, based on their beneficial pleiotropic feedbacks. However, epistasis between the two promising mutational spots in AzoA has not been obtained in terms of substrate binding and azoreductase activity. In this study, we further quantified, visualized, and described the pleiotropic and/or epistatic behavior of six single or double mutations at the positions, Arg-21 and Asn-121, as a further research endeavor for beneficial fine-tuning of AzoA. Based on this network-based mutational analysis, we showed that pleiotropy and epistasis are common, sensitive, and complex mutational behaviors, depending mainly on the structural and functional responsibility and the physicochemical properties of the residue(s) in AzoA.