Innate immunity activation involved in unprotected porcine auto-transplant kidneys preserved by naked caspase-3 siRNA

Long-Term Protection of CHBP Against Combinational Renal Injury Induced by Both Ischemia-Reperfusion and Cyclosporine A in Mice

Renal ischemia–reperfusion (IR) injury and cyclosporine A (CsA) nephrotoxicity affect allograft function and survival. The prolonged effects and underlying mechanisms of erythropoietin derived cyclic helix B peptide (CHBP) and/or caspase-3 small interfering RNA (CASP-3siRNA) were investigated in mouse kidneys, as well as kidney epithelial cells (TCMK-1), subjected to transplant-related injuries. Bilateral renal pedicles were clamped for 30 min followed by reperfusion for 2 and 8 weeks, with/without 35 mg/kg CsA gavage daily and/or 24 nmol/kg CHBP intraperitoneal injection every 3 days. The ratio of urinary albumin to creatinine was raised by IR injury, further increased by CsA and lowered by CHBP at 2, 4, 6 and 8 weeks, whereas the level of SCr was not significantly affected. Similar change trends were revealed in tubulointerstitial damage and fibrosis, HMGB1 and active CASP-3 protein. Increased apoptotic cells in IR kidneys were decreased by CsA and CHBP at 2 and/or 8 weeks. p70 S6 kinase and mTOR were reduced by CsA with/without CHBP at 2 weeks, so were S6 ribosomal protein and GSK-3β at 8 weeks, with reduced CASP-3 at both time points. CASP-3 was further decreased by CHBP in IR or IR + CsA kidneys at 2 or 8 weeks. Furthermore, in TCMK-1 cells CsA induced apoptosis was decreased by CHBP and/or CASP-3siRNA treatment. Taken together, CHBP predominantly protects kidneys against IR injury at 2 weeks and/or CsA nephrotoxicity at 8 weeks, with different underlying mechanisms. Urinary albumin/creatinine is a good biomarker in monitoring the progression of transplant-related injuries. CsA divergently affects apoptosis in kidneys and cultured kidney epithelial cells, in which CHBP and/or CASP-3siRNA reduces inflammation and apoptosis.

Large animal models for translational research in acute kidney injury

While extensive research using animal models has improved the understanding of acute kidney injury (AKI), this knowledge has not been translated into effective treatments. Many promising interventions for AKI identified in mice and rats have not been validated in subsequent clinical trials. As a result, the mortality rate of AKI patients remains high. Inflammation plays a fundamental role in the pathogenesis of AKI, and one reason for the failure to translate promising therapeutics may lie in the profound difference between the immune systems of rodents and humans. The immune systems of large animals such as swine, nonhuman primates, sheep, dogs and cats, more closely resemble the human immune system. Therefore, in the absence of a basic understanding of the pathophysiology of human AKI, large animals are attractive models to test novel interventions. However, there is a lack of reviews on large animal models for AKI in the literature. In this review, we will first highlight differences in innate and adaptive immunities among rodents, large animals, and humans in relation to AKI. After illustrating the potential merits of large animals in testing therapies for AKI, we will summarize the current state of the evidence in terms of what therapeutics have been tested in large animal models. The aim of this review is not to suggest that murine models are not valid to study AKI. Instead, our objective is to demonstrate that large animal models can serve as valuable and complementary tools in translating potential therapeutics into clinical practice.

Renal Delivery of Pharmacologic Agents During Machine Perfusion to Prevent Ischaemia-Reperfusion Injury: From Murine Model to Clinical Trials

Donor organ shortage still remains a serious obstacle for the access of wait-list patients to kidney transplantation, the best treatment for End-Stage Kidney Disease (ESKD). To expand the number of transplants, the use of lower quality organs from older ECD or DCD donors has become an established routine but at the price of increased incidence of Primary Non-Function, Delay Graft Function and lower-long term graft survival. In the last years, several improvements have been made in the field of renal transplantation from surgical procedure to preservation strategies. To improve renal outcomes, research has focused on development of innovative and dynamic preservation techniques, in order to assess graft function and promote regeneration by pharmacological intervention before transplantation. This review provides an overview of the current knowledge of these new preservation strategies by machine perfusions and pharmacological interventions at different timing possibilities: in the organ donor, ex-vivo during perfusion machine reconditioning or after implementation in the recipient. We will report therapies as anti-oxidant and anti-inflammatory agents, senolytics agents, complement inhibitors, HDL, siRNA and H2S supplementation. Renal delivery of pharmacologic agents during preservation state provides a window of opportunity to treat the organ in an isolated manner and a crucial route of administration. Even if few studies have been reported of transplantation after ex-vivo drugs administration, targeting the biological pathway associated to kidney failure (i.e. oxidative stress, complement system, fibrosis) might be a promising therapeutic strategy to improve the quality of various donor organs and expand organ availability.

Treatment of transplant kidneys during machine perfusion

The increasing use of donation after circulatory death (DCD) and extended criteria donor (ECD) organs has raised awareness of the need to improve the quality of kidneys for transplantation. Treating kidneys during the preservation interval could improve early and long-term graft function and survival. Dynamic modes of preservation including hypothermic machine perfusion (HMP) and normothermic machine perfusion (NMP) may provide the functional platforms to treat these kidneys. Therapies in the field of regenerative medicine including cellular therapies and genetic modification and the application of biological agents targeting ischaemia reperfusion injury (IRI) and acute rejection are a growing area of research. This review reports on the application of cellular and gene manipulating therapies, nanoparticles, anti-inflammatory agents, anti-thrombolytic agents and monoclonal antibodies administered during HMP and NMP in experimental models. The review also reports on the clinical effectiveness of several biological agents administered during HMP. All of the experimental studies provide proof of principle that therapies can be successfully delivered during HMP and NMP. However, few have examined the effects after transplantation. Evidence for clinical application during HMP is sparse and only one study has demonstrated a beneficial effect on graft function. More investigation is needed to develop perfusion strategies and investigate the different experimental approaches.

Pathogenesis of Chronic Allograft Dysfunction Progress to Renal Fibrosis

Kidney transplantation is a life-change measurement for the patients of end-stage renal disease (ESRD). However, the renal allograft cannot avoid initial acute kidney injury (AKI) and subsequent chronic allograft dysfunction (CAD), gradually develops fibrosis and eventually loses function. It is imperative to disclose the pathogenesis of AKI and CAD in order to facilitate interventions. We have studied the involvement of immunity, inflammation, and apoptosis in ischemia-reperfusion injury (IRI) and/or immunosuppressant induced AKI models, with associated chronic damage. Our research mainly focused on tubular epithelial cells (TECs) that are passive victims and also active participators in injury and mediate following repair or fibrosis. Targeting not only fibroblasts/myofibroblasts, but also TECs, might be a fundamental strategy to prevent and treat renal fibrosis. We have also evaluated the potential application of siRNA targeting caspase-3 and tissue protective erythropoietin derivatives, HBSP and CHBP, aiming to treat AKI and prevent CAD. Significant improvements have been obtained, but timely diagnosis and precise therapy of AKI and prevention of CAD progressing to ESRD are still very challenging. Modern technologies such as microarray and sequencing analysis have been used to identify biomarkers and potentially facilitate individual cell target treatment for transplant patients.

The Protective Effects of Helix B Surface Peptide on Experimental Acute Liver Injury Induced by Carbon Tetrachloride

BACKGROUND

To investigate the protective effects of helix B surface peptide (HBSP) on acute liver injury induced by carbon tetrachloride (CCl₄).

METHODS

HBSP (8 nmol/kg) was intraperitoneally injected into C57 BL/6 mice 2 h after CCl₄ administration. Serum and liver tissue samples were collected 24 h after injury. Liver function and histological injuries were evaluated. Inflammatory cell infiltration and cytokines were examined and hepatocytes apoptosis was measured. The human liver cell line LO2 and murine primary hepatocytes were stimulated by CCl₄ with and without HBSP treatment and glutathione peroxidase activity, cell survival, and apoptosis were evaluated. In addition, we examined the PI3K/Akt/mTORC1 pathway to elucidate the mechanism underlying HBSP-mediated protection in acute liver injury.

RESULTS

HBSP significantly decreased serum alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, and pro-inflammatory cytokines in liver tissues after CCl₄ injection compared with those in the control group. Immunohistochemical staining indicated that the number of CD3-, CD8-, and CD68-positive cells and the expression of cleaved caspase-3 were significantly decreased by HBSP treatment. Additionally, HBSP reduced apoptosis in vivo. In an in vitro study, the glutathione peroxidase activity and survival rate increased, while the total apoptotic rate was reduced in the HBSP-treated group compared with that in the control group after CCl₄ treatment. HBSP activated the PI3K/Akt/mTORC1 pathway, which was confirmed by the PI3K inhibitor LY294002 both in vivo and in vitro. Furthermore, HBSP increased the survival of mice with acute liver injury, and this effect was abolished by LY294002.

CONCLUSIONS

HBSP is a potential therapeutic agent against acute liver injury induced by CCl₄.

A novel cyclic helix B peptide inhibits dendritic cell maturation during amelioration of acute kidney graft rejection through Jak-2/STAT3/SOCS1

We recently synthesized a novel proteolysis-resistant cyclic helix B peptide (CHBP) that exhibits promising renoprotective effects. Dendritic cells (DCs) play an activation role in acute rejection (AR). Thus, the present study was designed to investigate the effects of CHBP on DCs in a rat renal transplantation model. The left kidney was harvested from male Lewis rats and then transplanted into male Wistar rats with or without CHBP treatment. Five successive treatment doses of CHBP after transplantation significantly ameliorated AR with lower histological injury, apoptosis and CD4⁺ and CD8⁺ T-cell infiltration in renal allografts. CHBP reduced IFN-γ and IL-1β levels but increased IL-4 and IL-10 levels in the serum. The number of mature DCs was significantly decreased in renal allografts treated with CHBP. In addition, incubating DCs with CHBP in vitro led to reduction in TNF-α, IFN-γ, IL-1β and IL-12 levels and increase of IL-10 expression at the protein level in the supernatant. Mechanistically, CHBP inhibited TLR activation-induced DC maturation by increasing SOCS1 expression through Jak-2/STAT3 signaling. In conclusion, CHBP suppresses renal allograft AR by inhibiting the maturation of DCs via Jak-2/STAT3/SOCS1 signaling, suggesting that CHBP may be an potential therapeutic drug for treating renal AR.

Cyclic helix B peptide inhibits ischemia reperfusion-induced renal fibrosis via the PI3K/Akt/FoxO3a pathway

Renal fibrosis is a main cause of end-stage renal disease. Clinically, there is no beneficial treatment that can effectively reverse the progressive loss of renal function. We recently synthesized a novel proteolysis-resistant cyclic helix B peptide (CHBP) that exhibits promising renoprotective effects. In this study, we evaluated the effect of CHBP on renal fibrosis in an in vivo ischemia reperfusion injury (IRI) model and in vitro TGF-β-stimulated tubular epithelial cells (TCMK-1 and HK-2) model. In the IRI in vivo model, mice were randomly divided into sham (sham operation), IR and IR + CHBP groups (n = 6). CHBP (8 nmol/kg) was administered intraperitoneally at the onset of reperfusion, and renal fibrosis was evaluated at 12 weeks post-reperfusion. Our results showed that CHBP markedly attenuated the IRI-induced deposition of collagen I and vimentin. In the in vitro model, CHBP reversed the TGF-β-induced down-regulation of E-cadherin and up-regulation of α-SMA and vimentin. Furthermore, CHBP inhibited the phosphorylation of Akt and Forkhead box O 3a (FoxO3a), whose anti-fibrotic effect could be reversed by the 3-phosphoinositide-dependent kinase-1 (PI3K) inhibitor wortmannin as well as FoxO3a siRNA. These findings demonstrate that CHBP attenuates renal fibrosis and the epithelial-mesenchymal transition of tubular cells, possibly through suppression of the PI3K/Akt pathway and thereby the inhibition FoxO3a activity.

Fighting against kidney diseases with small interfering RNA: opportunities and challenges

The significant improvements in siRNA therapy have been achieved, which have great potential applications in humans. The kidney is a comparatively easy target organ of siRNA therapy due to its unique structural and functional characteristics. Here, we reviewed recent achievements in siRNA design, delivery and application with focuses on kidney diseases, in particular kidney transplant-related injuries. In addition, the strategy for increasing serum stability and immune tolerance of siRNA was also discussed. At last, the future challenges of siRNA therapy including organ/tissue/cell-specific delivery and time-controlled silence, as well as selecting therapeutic targets, were addressed as well.

Emerging therapies targeting intra-organ inflammation in transplantation

Over the past several years, the field of transplantation has witnessed significant progress on several fronts; in particular, achievements have been made in devising novel immunosuppressive strategies. An under-explored area that may hold great potential to improve transplantation outcomes is the design of novel strategies to apply specifically to organs to reduce intra-graft inflammation. A growing body of evidence indicates a key role of intra-graft inflammatory cascade in potently instigating the alloimmune response. Indeed, controlling the activation of innate immunity/inflammatory responses has been shown to be a promising strategy to increase the graft acceptance and survival. In this minireview, we provide an overview of emerging targeted strategies, which can be directly applied to grafts to down-regulate intra-graft inflammation prior to transplantation.

A normative study of the synovial fluid proteome from healthy porcine knee joints

Synovial fluid in an articulating joint contains proteins derived from the blood plasma and proteins that are produced by cells within the joint tissues, such as synovium, cartilage, ligament, and meniscus. The proteome composition of healthy synovial fluid and the cellular origins of many synovial fluid components are not fully understood. Here, we present a normative proteomics study using porcine synovial fluid. Using our optimized method, we identified 267 proteins with high confidence in healthy synovial fluid. We also evaluated mRNA expression data from tissues that can contribute to the synovial fluid proteome, including synovium, cartilage, blood, and liver, to better estimate the relative contributions from these sources to specific synovial fluid components. We identified 113 proteins in healthy synovial fluid that appear to be primarily derived from plasma transudates, 37 proteins primarily derived from synovium, and 11 proteins primarily derived from cartilage. Finally, we compared the identified synovial fluid proteome to the proteome of human plasma, and we found that the two body fluids share many similarities, underlining the detected plasma derived nature of many synovial fluid components. Knowing the synovial fluid proteome of a healthy joint will help to identify mechanisms that cause joint disease and pathways involved in disease progression.

Rapamycin protects kidney against ischemia reperfusion injury through recruitment of NKT cells

Background

NKT cells play a protective role in ischemia reperfusion (IR) injury, of which the trafficking in the body and recruitment in injured organs can be influenced by immunosuppressive therapy. Therefore, we investigated the effects of rapamycin on kidneys exposed to IR injury in early stage and on trafficking of NKT cells in a murine model.

Material and methods

Balb/c mice were subjected to kidney 30 min ischemia followed by 24 h reperfusion. Rapamycin (2.5 ml/kg) was administered by gavage daily, starting 1 day before the operation. Renal function and histological changes were assessed. The proportion of NKT cells in peripheral blood, spleen and kidney was detected by flow cytometry. The chemokines and corresponding receptor involved in NKT cell trafficking were determined by RT-PCR and flow cytometry respectively.

Results

Rapamycin significantly improved renal function and ameliorated histological injury. In rapamycin-treated group, the proportion of NKT cells in spleen was significantly decreased but increased in peripheral blood and kidney. In addition, the CXCR3⁺ NKT cell in the kidney increased remarkably in the rapamycin-treated group. The chemokines, CXCL9 and CXCL10, as the ligands of CXCR3, were also increased in the rapamycin-treated kidney.

Conclusions

Rapamycin may recruit NKT cells from spleen to the IR-induced kidney to ameliorate renal IR injury in the early stage.

Immunotherapy of hepatocellular carcinoma with small double-stranded RNA

Background

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with limited therapeutic options. Since HCC has been shown to be immunogenic, immunotherapy is considered a promising therapeutic approach. Small interfering RNAs (siRNAs), depending on their structure and sequence, can trigger the innate immune system, which can potentially enhance the adaptive anticancer immune response in the tumor-bearing subjects. Immunostimulatory properties of nucleic acids can be applied to develop adjuvants for HCC treatment.

Methods

The transplantable HCC G-29 tumor in male CBA/LacSto (CBA) mice was used to study the effects of immunostimulatory RNA on tumor growth. Tumor size, metastases area in different organs of mice and mouse survival rate were analyzed. Furthermore the mouse serum IFN-α levels were measured using ELISA.

Results

In the present study, we found that a 19-bp RNA duplex (ImmunoStimulattory RNA or isRNA) with 3-nt overhangs at the 3′-ends of specific sequence displays immunostimulatory, antitumor, and antimetastatic activities in mice bearing HCC G-29. Our results demonstrate that isRNA strongly increases the level of interferon-α (IFN-α) by up to 25-fold relative to the level in mice injected with Lipofectamine alone (Mock), and to a lesser extent increases the level of proinflammatory cytokine interleukin-6 (IL-6) (by up to 5.5-fold relative to the Mock level), in mice blood serum. We showed that isRNA reliably (P < 0.05) inhibits primary tumor growth in mice compared to the mock group. Furthermore, injections of isRNA significantly enhanced necrotic processes in the center of the primary tumor, and decreased by twofold the width of the undifferentiated peripheral zone and the number of mitotic cells in this zone. The results showed that isRNA efficiently reduces the area of metastases in the liver, kidneys, and heart of CBA/LacSto mice with HCC.

Conclusions

The obtained results clearly demonstrate immunostimulatory and antimetastatic properties of the isRNAs in mice with HCC. Consequently, this short double-stranded RNA can be considered as a potential adjuvant for the therapy of HCC.