Evaluation of Pulsatile Perfusion Machine RM3 for Kidney Preservation in a Swine Model of Renal Autotransplantation

Porcine ubiquitin-like protein MNSFβ promotes cell apoptosis and covalently binds to BCL-G to enhance staurosporine-induced apoptosis

Background

Monoclonal non-specific suppressor factor β (MNSFβ) is a ubiquitously expressed member of the ubiquitin-like family. It functions as a regulator of cell apoptosis and a potential tumor suppressor, playing a vital role in the processes of immune cell function and apoptosis.

Methods

The present study constructed GFP-pMNSFβ swine umbilical vein endothelial cell (SUVEC) lines and investigated the function of porcine MNSFβ (pMNSFβ) in apoptosis, as well as its interactions with pBCL-G. Results revealed that stably expressed pMNSFβ protein in SUVEC lines significantly enhanced staurosporine (STS)-induced apoptosis. pMNSFβ proteins interacted with pBCL-G proteins and the expression of these interacting proteins synergized to further enhance STS-induced apoptosis.

Results

GFP-pMNSFβ stably expressed SUVEC lines through transient transfection and neomycin screening methods. Over 90% of the SUVEC cultures expressed GFP signals, and 41.5 kDa GFP-pMNSFβ proteins were detected with western blotting methods. Annexin V-PE/PI staining and flow cytometry analyses showed that overexpression of pMNSFβ proteins significantly elevated STS-induced apoptosis rates. Co-immunoprecipitation methods revealed an interaction between pMNSFβ and pBCL-G proteins. BCL-G is a proapoptotic member of the BCL-2 family that has been shown to be misexpressed in human systemic lupus erythematosus, as well as mammary and prostate cancers. Here, we demonstrated that the co-expression and potential conjugation of pMNSFβ and pBCL-G proteins synergistically enhanced STS-induced apoptosis.

Conclusions

The present study was the first to characterize the function of MNSFβ in porcine cells, and to clarify the function of MNSFβ in apoptosis. These results reveal that pMNSFβ is a potential molecular model for future investigations of diseases related to human MNSFβ dysfunction.

Cloning, tissue distribution, expression pattern, and function of porcine maternal embryonic leucine zipper kinase

Background

Maternal embryonic leucine zipper kinase (MELK) is an atypical member of the snf1/AMPK family of serine-threonine kinases, involved in diverse physiological and pathological processes, including cell proliferation, apoptosis, embryogenesis, cancer treatment resistance, and RNA processing. MELK is highly expressed in human cancers and is associated with more aggressive forms of astrocytoma, glioblastoma, breast cancer, and melanoma to date, no information about porcine MELK (pMELK) has been reported.

Methods

In this study, the pMELK coding sequence was cloned from swine spleen and characterized. We also quantitatively determined the expression of MELK in 11 tissues isolated from a piglet and determined its subcellular localization when expressed in swine umbilical vein endothelial cells (SUVEC) as a fusion protein. Moreover, we report the functional characterization of pMELK protein concerning its role in apoptosis.

Results

Sequencing analysis showed that full-length of pMELK is 2,072 bp with 17 exons, encoding 655 amino acids, including an S-TKc conserved domain. Comparison of pMELK with ten other mammalian species of their orthologous sequences showed >91% homology and an evolutionary distance <0.05, demonstrating that MELK is highly conserved in evolution. Relative quantification of MELK expression in 11 tissue samples isolated from 30-day-old piglets showed MELK expression in all tested organs and the highest expression in the superficial inguinal lymph node. Constructed a plasmid named pEGFP-MELK, and the fusion protein GFP-MELK was successfully expressed in SUVECs. Fluorescence microscopy revealed the subcellular distribution of the fusion protein GFP-MELK was limited to the cytoplasm. About function, Flow cytometry analysis showed that overexpression of GFP-pMELK in SUVEC cells enhances staurosporine (STS)—induced apoptosis, but not significantly different. The pMELK protein also was found to interact with porcine BCL-G and transient transfection of the recombinant plasmid pCMV-HA-pMELK into SUVEC cells stably expressing GFP-pBCL-G protein inhibited pBCL-G -induced apoptosis significantly.

Conclusions

The present study provided useful information on pMELK basic details and function in apoptosis offer a potential new molecular model for disease interventions and disease related to human MELK and BCL-G.

Chronic renoprotective effect of pulsatile perfusion machine RM3 and IGL-1 solution in a preclinical kidney transplantation model

BACKGROUND

Machine perfusion (MP) of kidney graft provides benefits against preservation injury, however decreased graft quality requires optimization of the method. We examined the chronic benefits of MP on kidney grafts and the potential improvements provided by IGL-1 solution.

METHOD

We used an established autotransplantation pig kidney model to study the effects of MP against the deleterious effects of warm ischemia (WI: 60 minutes) followed by 22 hours of cold ischemia in MP or static cold storage (CS) followed by autotransplantation. MPS and IGL-1 solutions were compared.

RESULTS

Animal survival was higher in MPS-MP and both IGL groups. Creatinine measurement did not discriminate between the groups, however MPS-MP and both IGL groups showed decreased proteinuria. Chronic fibrosis level was equivalent between the groups. RTqPCR and immunohistofluorescent evaluation showed that MP and IGL-1 provided some protection against epithelial to mesenchymal transition and chronic lesions. IGL-1 was protective with both MP and CS, particularly against chronic inflammation, with only small differences between the groups.

CONCLUSION

IGL-1 used in either machine or static preservation offers similar levels of protection than standard MP. The compatibility of IGL-1 with both machine perfusion and static storage could represent an advantage for clinical teams when choosing the correct solution to use for multi-organ collection. The path towards improving machine perfusion, and organ quality, may involve the optimization of the solution and the correct use of colloids.

Renoprotective effect of pulsatile perfusion machine RM3: pathophysiological and kidney injury biomarker characterization in a preclinical model of autotransplanted pig

OBJECTIVES

To assess the effect of machine perfusion (MP) on renal function recovery vs kidney preservation in static cold storage (CS), in a large animal preclinical model. To assess whether MP benefits are dependent on the preservation solution used.

METHODS

Using an established autotransplantation pig kidney model associated with a contralateral nephrectomy we studied the impact of MP against the deleterious effects of warm ischaemia (WI; 60 min), then 22 h of cold ischaemia using MP or static CS, followed by autotransplantation. We used Berzer MP solution (MPS), recommended for MP, and Institut Georges Lopez preservation solution (IGL-1), designed for CS. The pigs were divided into four study groups: MPS-CS: static CS with MPS (n = 7); MPS-MP: renal perfusion with MPS using the Waters Medical Systems (Rochester, MN, USA) RM3 pulsatile machine (n = 7); IGL-CS: static CS with IGL-1 solution (n = 7); IGL-MP: renal perfusion with IGL-1 solution (n = 7). The effect of ischaemia was determined using different variables: pig survival; plasma creatinine; proteinuria; oxidative stress; tubular sodium reabsorption rate; and tissue damage at 1 month.

RESULTS

Pig survival was higher in MP and IGL groups compared to MPS-CS. Plasma creatinine levels did not differ among the groups, but proteinuria assay showed significant benefits for the MP vs static CS groups. Histological evaluation of kidney grafts showed more injury in the CS groups than in the MP groups. Urinary measurement of tubular enzyme activity differed substantially among the groups, highlighting the benefits of MP in maintaining brush border integrity.

CONCLUSIONS

In our model reproducing the conditions of deceased after cardiac arrest donors we show that MP decreases the risk of renal dysfunction and preserves kidney parenchyma. A non-invasive urinary enzyme assay can provide valuable information on graft integrity. The preservation solution used is important as the wrong solution can decrease the benefits of MP.