Production of bioactive recombinant human myeloid-derived growth factor in Escherichia coli and its mechanism on vascular endothelial cell proliferation

Myeloid-derived growth factor and its effects on cardiovascular and metabolic diseases

Myeloid-derived growth factor (MYDGF) is a paracrine protein produced by bone marrow-derived monocytes and macrophages. Current research shows that it has protective effects on the cardiovascular system, such as repairing heart tissue after myocardial infarction, enhancing cardiomyocyte proliferation, improving cardiac regeneration after myocardial injury, regulating proliferation and survival of endothelial cells, reducing endothelial cell damage, resisting pressure overload-induced heart failure, as well as protecting against atherosclerosis. Furthermore, regarding the metabolic diseases, MYDGF has effects of improving type 2 diabetes mellitus, relieving non-alcoholic fatty liver disease, alleviating glomerular diseases, and resisting osteoporosis. Herein, we will discuss the biology of MYDGF and its effects on cardiovascular and metabolic diseases.

Identification of myeloid-derived growth factor as a mechanically-induced, growth-promoting angiocrine signal for human hepatocytes

Recently, we have shown that after partial hepatectomy (PHx), an increased hepatic blood flow initiates liver growth in mice by vasodilation and mechanically-triggered release of angiocrine signals. Here, we use mass spectrometry to identify a mechanically-induced angiocrine signal in human hepatic endothelial cells, that is, myeloid-derived growth factor (MYDGF). We show that it induces proliferation and promotes survival of primary human hepatocytes derived from different donors in two-dimensional cell culture, via activation of mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3). MYDGF also enhances proliferation of human hepatocytes in three-dimensional organoids. In vivo, genetic deletion of MYDGF decreases hepatocyte proliferation in the regenerating mouse liver after PHx; conversely, adeno-associated viral delivery of MYDGF increases hepatocyte proliferation and MAPK signaling after PHx. We conclude that MYDGF represents a mechanically-induced angiocrine signal and that it triggers growth of, and provides protection to, primary mouse and human hepatocytes.

The promotion of sestrin2/AMPK signaling by HIF-1α overexpression enhances the damage caused by acute myocardial infarction

OBJECTIVE

Acute myocardial infarction (AMI), is a serious form of coronary heart disease. The present study sought to investigate the impact of HIF-1α on AMI, along with its fundamental mechanism.

METHODS

Sprague-Dawley (SD) rats were used to conduct an AMI model. 2,3,5-triphenyl-2H-tetrazolium chloride (TTC) staining was used examine the region of myocardial infract area at various time intervals. Protein expression levels were detected using western blotting. The rats were randomly divided into sham, model, negative control (NC), HIF-1α overexpression (HIF-1α-OE), and HIF-1α-OE+ si-sestrin2 groups. We examined the impact of HIF-1α overexpression on AMI rats using Haematoxylin-Eosin (H&E) staining, TTC staining, enzyme-linked immunosorbent assay (ELISA), TdT-mediated dUTP Nick-End Labeling (TUNEL) assay, and immunohistochemistry (IHC) staining.

RESULTS

According to the TTC findings, the region affected by myocardial infarction reached its peak at day 14. Based on the results from the western blot analysis, the levels of HIF-1α and sestrin2 were found the minimum on day 28. Subsequently, we discovered that the overexpression of HIF-1α rescued the cardiac function parameters, improved the morphology of myocardial tissue, and mitigated inflammation. Furthermore, the overexpression of HIF-1α led to a reduction in the levels of MDA and an increase in the levels of SOD. Moreover, the overexpression of HIF-1α resulted in a decrease in cellular apoptosis. This result was confirmed by the expression levels of Bcl-2 and Bax. Nevertheless, the defensive impact of elevated HIF-1α expression was somewhat counteracted by the suppression of sestrin2. In terms of mechanism, the overexpression of HIF-1α enhanced the levels of sestrin2 and the protein adenosine monophosphate activated kinase (AMPK).

CONCLUSION

Our research suggests that the overexpression of HIF-1α may rescue the damage to myocardial tissue, and this effect is associated with the sestrin2/AMPK signaling pathway. Our study provides a novel comprehension of the protective effects of HIF-1α overexpression on AMI.

rhMYDGF Alleviates I/R-induced Kidney Injury by Inhibiting Inflammation and Apoptosis via the Akt Pathway

BACKGROUND

Renal ischemia/reperfusion (I/R) injury is one of the crucial factors affecting the outcome of renal transplantation. In recent years, myeloid-derived growth factor (MYDGF) has received a lot of attention for its extensive beneficial effects on cardiac repair and protection of cardiomyocytes from cell death. Therefore, we hypothesized that the recombinant human MYDGF (rhMYDGF) protein might play an essential role in safeguarding renal I/R injury.

METHODS

In vivo experiments were conducted using a mouse unilateral I/R model. Mice were pretreated with rhMYDGF by intraperitoneal injection to study the potential mechanism of renal protection. In vitro, we established hypoxia/reoxygenation and H 2 O 2 treatment models to pretreat cells with rhMYDGF. The expression levels of oxidative stress, inflammation, and apoptosis-related factors in tissues and cells were detected. Finally, we explored the role of the protein kinase B (Akt) pathway in the renal protective mechanism of rhMYDGF.

RESULTS

In this study, we found that intraperitoneal injection of 1.25 μg rhMYDGF could significantly improve renal function of I/R mice, and reduce oxidative stress, inflammation, and apoptosis. For the human proximal tubular epithelial cell line and human kidney cell line, pretreatment with 0.3 μg/mL rhMYDGF for 24 h significantly downregulated oxidative stress, inflammation, and apoptosis via the phosphorylation of Akt, which could be ameliorated by LY294002.

CONCLUSIONS

rhMYDGF protects kidney from I/R injury by attenuating oxidative stress, inflammation, and apoptosis through the activation of the Akt pathway.

Future regenerative medicine developments and their therapeutic applications

Although the currently available pharmacological assays can cure most pathological disorders, they have limited therapeutic value in relieving certain disorders like myocardial infarct, peripheral vascular disease, amputated limbs, or organ failure (e.g. renal failure). Pilot studies to overcome such problems using regenerative medicine (RM) delivered promising data. Comprehensive investigations of RM in zebrafish or reptilians are necessary for better understanding. However, the precise mechanisms remain poorly understood despite the tremendous amount of data obtained using the zebrafish model investigating the exact mechanisms behind their regenerative capability. Indeed, understanding such mechanisms and their application to humans can save millions of lives from dying due to potentially life-threatening events. Recent studies have launched a revolution in replacing damaged human organs via different approaches in the last few decades. The newly established branch of medicine (known as Regenerative Medicine aims to enhance natural repair mechanisms. This can be done through the application of several advanced broad-spectrum technologies such as organ transplantation, tissue engineering, and application of Scaffolds technology (support vascularization using an extracellular matrix), stem cell therapy, miRNA treatment, development of 3D mini-organs (organoids), and the construction of artificial tissues using nanomedicine and 3D bio-printers. Moreover, in the next few decades, revolutionary approaches in regenerative medicine will be applied based on artificial intelligence and wireless data exchange, soft intelligence biomaterials, nanorobotics, and even living robotics capable of self-repair. The present work presents a comprehensive overview that summarizes the new and future advances in the field of RM.

Role of Mydgf in the regulation of hypoxia/reoxygenation-induced apoptosis in cardiac microvascular endothelial cells

We aimed to explore the effects of myeloid-derived growth factor (Mydgf) on the regulation of hypoxia/reoxygenation (HR)-induced apoptosis of cardiac microvascular endothelial cells (CMECs). CMECs were exposed to hypoxia for 24 h and reoxygenation for 6 h to establish an HR cell model. Subsequently, an adenovirus was used to overexpress Mydgf in CMECs. Flow cytometry and TUNEL staining were used to detect the extent of apoptosis, whereas qPCR was used to detect the relative expression of Mydgf mRNA. Western blotting was also performed to detect the expression of apoptosis-related proteins and endoplasmic reticulum stress (ERS)-related proteins, including C/EBP Homologous Protein (CHOP), glucose-regulated protein 78 (GRP 78), and cleaved Caspase-12. The endoplasmic reticulum stress agonist tunicamycin (TM) was used to stimulate CMECs for 24 h as a rescue experiment for Mydgf. Flow cytometry revealed that the HR model effectively induced endothelial cell apoptosis, whereas qPCR and western blotting showed that Mydgf mRNA and protein levels decreased significantly after HR treatment (P < 0.05). Overexpression of Mydgf in cells effectively reduced apoptosis after HR. Furthermore, western blotting showed that HR induced a significant upregulation of CHOP, GRP78, and cleaved-Caspase-12 expression in CMECs, whereas HR-treated cells downregulated the expression of CHOP, GRP78, and cleaved-Caspase-12 after Mydgf overexpression. Under HR conditions, TM significantly reversed the protective effect of Mydgf on CMECs. Mydgf may reduce CMEC apoptosis induced by HR by regulating oxidative stress in ERS.

Mucin-fused myeloid-derived growth factor (MYDGF164) exhibits a prolonged half-life and alleviates fibrosis in CKD

BACKGROUND AND PURPOSE

Currently, no effective therapy is available to completely stop or reverse CKD progression targeting its key feature, loss of peritubular capillaries (PTCs) leading to interstitial fibrosis, while Myeloid-derived growth factor (MYDGF) with tissue-repairing activities enlightened its therapeutic potential. However, the extremely short circulatory lifetime (15 minutes) restricts its applications.

EXPERIMENTAL APPROACH

We selected a tandem repeated (TR) region of human CD164 as a carrier to fuse with MYDGF and investigated the biophysical and pharmacokinetic changes. The MYDGF164 bioactivities were validated in HUVECs and assessed in HK-2 cells. Then, we investigated its efficacy in unilateral ureteral obstruction (UUO)-treated mice and adenine-induced CKD rats.

KEY RESULTS

MYDGF164 was intensively modified with sialoglycans, improving its resistance to serum proteases and increasing hydrodynamic radius. The half-life of MYDGF164 was significantly prolonged. MYDGF164 retained the original cell proliferation, anti-apoptosis, and tubulogenesis activities. It selectively stimulated the proliferation in endothelial and epithelial cells through phosphorylating MAPK1/3. MYDGF164 alleviated capillary rarefaction, hypoxia, renal fibrosis, and tubular atrophy in the UUO mice and adenine-induced CKD rats. Moreover, MYDGF164 restored renal function with normalized creatinine and urea levels in adenine-induced CKD rats. Histopathology and immunohistochemistry results revealed that the protection of MYDGF164 was related to its cell-proliferative, anti-apoptosis, and angiogenesis activities.

CONCLUSIONS AND IMPLICATIONS

This study is the first successful example of using a tandem repeated region of hCD164 as a cargo protein for the pharmacokinetic improvement of therapeutic proteins. Our findings also suggest the potential of MYDGF164 in alleviating renal fibrosis in CKD.

The Clinical Relevance and Tumor Promoting Function of C19orf10 in Kidney Renal Clear Cell Carcinoma

Kidney renal clear cell carcinoma (KIRC) is the most common primary renal neoplasms. Currently, there are few molecular indicators and therapeutic targets that can be used in diagnostic and prognostic assessment. In this study, we identified the C19orf10 expression in KIRC specimens and explored the diagnostic and prognostic value of C19orf10 in KIRC using TCGA and CPTAC database. Loss-of- and gain-of- function of C19orf10 was performed to investigate the roles of C19orf10 on KIRC cell viability, proliferation, migration and invasion via CCK-8, Edu incorporation and Transwell assays respectively. C19orf10 was overexpressed in KIRC tissues and the elevated C19orf10 expression was closely associated with clinicopathological characteristics of KIRC including histological grade, TNM stage, metastatic status. Silencing C19orf10 significantly suppressed the viability, proliferation, migration and invasion ability, while overexpression of C19orf10 promoted the progression and malignant phenotype in KIRC cells. Furthermore, C19orf10 exerted its carcinogenic function by regulating ZO-1 and PTEN/Akt signaling pathway. Moreover, the Kaplan–Meier survival analysis, Cox regression analysis and receiver operating curve analysis showed that patients with C19orf10 overexpression have poor survival time. C19orf10 could discriminate KIRC patients with high-risk from low-risk. Taken together, C19orf10 contributes to KIRC development via ZO-1 and PTEN/Akt signaling pathway and C19orf10 could serve as a potential diagnostic and prognostic candidate and therapeutic target of KIRC.

Mydgf promotes Cardiomyocyte proliferation and Neonatal Heart regeneration

Myeloid-derived growth factor (Mydgf), a paracrine protein secreted by bone marrow-derived monocytes and macrophages, was found to protect against cardiac injury following myocardial infarction (MI) in adult mice. We speculated that Mydgf might improve heart function via myocardial regeneration, which is essential for discovering the target to reverse heart failure. Methods: Two genetic mouse lines were used: global Mydgf knockout (Mydgf-KO) and Mydgf-EGFP mice. Two models of cardiac injury, apical resection was performed in neonatal and MI was performed in adult mice. Quantitative reverse transcription-polymerase chain reaction, western blot and flow cytometry were performed to study the protein expression. Immunofluorescence was performed to detect the proliferation of cardiomyocytes. Heart regeneration and cardiac function were evaluated by Masson's staining and echocardiography, respectively. RNA sequencing was employed to identify the key involved in Mydgf-induced cardiomyocyte proliferation. Mydgf recombinant protein injection was performed as a therapy for cardiac repair post MI in adult mice. Results: Mydgf expression could be significantly induced in neonatal mouse hearts after cardiac injury. Unexpectedly, we found that Mydgf was predominantly expressed by endothelial cells rather than macrophages in injured neonatal hearts. Mydgf deficiency impeded neonatal heart regeneration and injury-induced cardiomyocyte proliferation. Mydgf recombinant protein promoted primary mouse cardiomyocyte proliferation. Employing RNA sequencing and functional verification, we demonstrated that c-Myc/FoxM1 pathway mediated Mydgf-induced cardiomyocyte expansion. Mydgf recombinant protein improved cardiac function in adult mice after MI injury with inducing cardiomyocyte proliferation. Conclusion: Mydgf promotes cardiomyocyte proliferation by activating c-Myc/FoxM1 pathway and improves heart regeneration both in neonatal and adult mice after cardiac injury, providing a potential target to reverse cardiac remodeling and heart failure.

Production of bioactive recombinant human myeloid-derived growth factor in Escherichia coli and its mechanism on vascular endothelial cell proliferation

Myeloid‐derived growth factor (MYDGF) is a novel protein secreted by bone marrow cells that features important physiological functions. In recent years, MYDGF has gained considerable interest due to their extensive beneficial effect on cardiac repair and protects cardiomyocytes from cell death. However, its precise molecular mechanisms have not been well elucidated. The purpose of this study was to produce sufficient amount of biologically active recombinant human (rh) MYDGF more economically and effectively by using in vitro molecular cloning techniques to study its clinical application. The prokaryotic expression system of Escherichia coli was established for the preparation of rhMYDGF. Finally, a large amount of high biologically active and purified form of recombinant protein was obtained. Moreover, we investigated the potential mechanism of rhMYDGF‐mediated proliferation and survival in human coronary artery endothelial cells (HCAECs). Mechanistically, the results suggested that MAPK/STAT3 and the cyclin D1 signalling pathways are indispensable for rhMYDGF‐mediated HCAEC proliferation and survival. Therefore, this study successfully established a preparation protocol for biologically active rhMYDGF and it may be a most economical way to produce high‐quality active rhMYDGF for future clinical application.