Cold Storage Disrupts the Proteome and Phosphoproteome Landscape in Rat Kidney Transplants.

Background: Prolonged cold storage (CS) of kidneys results in poor long-term outcomes after transplantation (Tx). We reported previously that CS of rat kidneys for 18 h before transplant impaired proteasome function, disrupted protein homeostasis, and reduced graft function. The goal of the present study was to identify the renal proteins, including phosphoproteins, that are dysregulated by this CS injury.

Normal Proteasome Function Is Needed to Prevent Kidney Graft Injury during Cold Storage Followed by Transplantation.

Kidney transplantation is the preferred treatment for end-stage kidney disease (ESKD). However, there is a shortage of transplantable kidneys, and donor organs can be damaged by necessary cold storage (CS). Although CS improves the viability of kidneys from deceased donors, prolonged CS negatively affects transplantation outcomes.

Cold Storage Followed by Transplantation Induces Immunoproteasome in Rat Kidney Allografts: Inhibition of Immunoproteasome Does Not Improve Function.

Key Points: Cold storage (CS) increases the severity of graft dysfunction in a time-dependent manner, and prolonged CS decreases animal survival. CS plus transplant increases iproeasome levels/assembly in renal allografts; IFN- is a potential inducer of the iproteasome. Inhibiting iproteasome during renal CS did not confer graft protection after transplantation.

Cold Storage Followed by Transplantation Induces Interferon-Gamma and STAT-1 in Kidney Grafts.

Cold storage (CS)-mediated inflammation, a reality of donor kidney processing and transplantation, can contribute to organ graft failure. However, the mechanisms by which this inflammation is perpetuated during and after CS remain unclear. Here, we examined the immunoregulatory roles of signal transducer and activator of transcription (STAT) family proteins, most notably STAT1 and STAT3, with our in vivo model of renal CS and transplant.

Aberrant activation of the complement system in renal grafts is mediated by cold storage.

Aberrant complement activation leads to tissue damage during kidney transplantation, and it is recognized as an important target for therapeutic intervention. However, it is not clear whether cold storage (CS) triggers the complement pathway in transplanted kidneys. The goal of the present study was to determine the impact of CS on complement activation in renal transplants.

The BK activator NS11021 partially protects rat kidneys from cold storage and transplantation-induced mitochondrial and renal injury.

Kidneys from deceased donors used for transplantation are placed in cold storage (CS) solution during the search for a matched recipient. However, CS induces mitochondrial and cellular injury, which exacerbates renal graft dysfunction, highlighting the need for therapeutic interventions. Using an in vitro model of renal CS, we recently reported that pharmacological activation of the mitochondrial BK channel (mitoBK) during CS protected against CS-induced mitochondrial injury and cell death.

Targeting Mitochondria during Cold Storage to Maintain Proteasome Function and Improve Renal Outcome after Transplantation.

Kidney transplantation is the preferred treatment for end-stage kidney disease (ESKD). Compared to maintenance dialysis, kidney transplantation results in improved patient survival and quality of life. Kidneys from living donors perform best; however, many patients with ESKD depend on kidneys from deceased donors.

Cold Storage Increases Albumin and Advanced Glycation-End Product-Albumin Levels in Kidney Transplants: A Possible Cause for Exacerbated Renal Damage.

Unlabelled: Prolonged cold storage (CS) of kidneys is associated with poor renal outcome after transplantation (Tx). We recently showed that in rats (Lewis), proteasome and renal function were severely compromised in kidney transplants subjected to CS (CS/Tx) as compared with those without CS exposure (autotransplanted [ATx]).

Methods: Evaluation of whole-kidney extracts from our rat kidney transplant model showed a subset of proteins induced after CS/Tx when compared with ATx or sham groups; this study examined those proteins using mass spectrometry, western blotting, immunoprecipitation, and immunohistochemistry.

The first direct activity assay for the mitochondrial protease OMA1.

Mitochondria continually undergo fission and fusion which allow mitochondria to rapidly change their shape, size, and function throughout the cell life cycle. OMA1, a zinc metalloproteinase enzyme, is a key regulator of the mitochondrial fusion machinery. The paucity of information regarding OMA1 regulation and function largely stems from the fact that there is no direct method to quantitatively measure its activity.

A Cycle of Altered Proteasome and Reactive Oxygen Species Production in Renal Proximal Tubular Cells.

Aims: An intricate relationship exists between the mitochondrial function and proteasome activity. Our recent report showed in a rat model of renal transplantation that mitochondrial dysfunction precedes compromised proteasome function and this results in a vicious cycle of mitochondrial injury and proteasome dysfunction. In this study, we studied whether reactive oxygen species (ROS) has a role in proteasome alteration in renal cells and

Methods: We used the genomic and pharmacologic approach on rat normal kidney proximal tubular (NRK) cell lines.

Renal cold storage followed by transplantation impairs proteasome function and mitochondrial protein homeostasis.

Identifying pathways related to renal cold storage (CS) that lead to renal damage after transplantation (Tx) will help us design novel pathway-specific therapies to improve graft outcome. Our recent report showed that mitochondrial function was compromised after CS alone, and this was exacerbated when CS was combined with Tx (CS/Tx). The goal of this study was to determine whether the proteasome exacerbates mitochondrial dysfunction after CS/Tx.

Renal cold storage followed by transplantation impairs expression of key mitochondrial fission and fusion proteins.

Background: The majority of transplanted kidneys are procured from deceased donors which all require exposure to cold storage (CS) for successful transplantation. Unfortunately, this CS leads to renal and mitochondrial damage but, specific mitochondrial targets affected by CS remain largely unknown. The goal of this study is to determine whether pathways involved with mitochondrial fusion or fission, are disrupted during renal CS.

Inactivation of renal mitochondrial respiratory complexes and manganese superoxide dismutase during sepsis: mitochondria-targeted antioxidant mitigates injury.

Acute kidney injury (AKI) is a complication of sepsis and leads to a high mortality rate. Human and animal studies suggest that mitochondrial dysfunction plays an important role in sepsis-induced multi-organ failure; however, the specific mitochondrial targets damaged during sepsis remain elusive. We used a clinically relevant cecal ligation and puncture (CLP) murine model of sepsis and assessed renal mitochondrial function using high-resolution respirometry, renal microcirculation using intravital microscopy, and renal function.

Replenishment of the B cell compartment after doxorubicin-induced hematopoietic toxicity is facilitated by STAT1.

STAT1 serves as an important regulator in the response to pathogens, oncogenic transformation, and genotoxic insults. It exerts these effects by shaping the innate and adaptive immune response and by participating in genotoxic stress pathways, leading to apoptosis and inhibition of cell proliferation. We have investigated the role of STAT1 in hematopoietic toxicity induced by doxorubicin in STAT1-proficient and -deficient mice.

Lapatinib and doxorubicin enhance the Stat1-dependent antitumor immune response.

The dual erbB1/2 tyrosine kinase inhibitor lapatinib as well as the anthracycline doxorubicin are both used in the therapy of HER2-positive breast cancer. Using MMTV-neu mice as an animal model for HER2-positive breast cancer, we observed enhanced tumor infiltration by IFN-γ-secreting T cells after treatment with doxorubicin and/or lapatinib. Antibody depletion experiments revealed a contribution of CD8⁺ but not CD4⁺ T cells to the antitumor effect of these drugs.

The use of the Cre/loxP system to study oxidative stress in tissue-specific manganese superoxide dismutase knockout models.

Significance: Respiring mitochondria are a significant site for reactions involving reactive oxygen and nitrogen species that contribute to irreversible cellular, structural, and functional damage leading to multiple pathological conditions. Manganese superoxide dismutase (MnSOD) is a critical component of the antioxidant system tasked with protecting the oxidant-sensitive mitochondrial compartment from oxidative stress. Since global knockout of MnSOD results in significant cardiac and neuronal damage leading to early postnatal lethality, this approach has limited use for studying the mechanisms of oxidant stress and the development of disease in specific tissues lacking MnSOD.

Role of reduced manganese superoxide dismutase in ischemia-reperfusion injury: a possible trigger for autophagy and mitochondrial biogenesis?

Excessive generation of superoxide and mitochondrial dysfunction has been described as being important events during ischemia-reperfusion (I/R) injury. Our laboratory has demonstrated that manganese superoxide dismutase (MnSOD), a major mitochondrial antioxidant that eliminates superoxide, is inactivated during renal transplantation and renal I/R and precedes development of renal failure. We hypothesized that MnSOD knockdown in the kidney augments renal damage during renal I/R.

MitoQ blunts mitochondrial and renal damage during cold preservation of porcine kidneys.

Cold preservation has greatly facilitated the use of cadaveric kidneys for transplantation but damage occurs during the preservation episode. It is well established that oxidant production increases during cold renal preservation and mitochondria are a key target for injury. Our laboratory has demonstrated that cold storage of renal cells and rat kidneys leads to increased mitochondrial superoxide levels and mitochondrial electron transport chain damage, and that addition of Mitoquinone (MitoQ) to the preservation solutions blunted this injury.

Utility of post-urinary tract infection imaging in patients with normal prenatal renal ultrasound.

The American Academy of Pediatrics recommends renal ultrasound (RUS) and voiding cystourethrography (VCUG) for all infants after a first urinary tract infection (UTI). However, many congenital renal anomalies are identified by a prenatal US. At the present time, there are no data regarding the yield of post-UTI imaging among infants who have a documented normal prenatal US.

Generation and characterization of a novel kidney-specific manganese superoxide dismutase knockout mouse.

Inactivation of manganese superoxide dismutase (MnSOD), a mitochondrial antioxidant, has been associated with renal disorders and often results in detrimental downstream events that are mechanistically not clear. Development of an animal model that exhibits kidney-specific deficiency of MnSOD would be extremely beneficial in exploring the downstream events that occur following MnSOD inactivation. Using Cre-Lox recombination technology, kidney-specific MnSOD deficient mice (both 100% and 50%) were generated that exhibited low expression of MnSOD in discrete renal cell types and reduced enzymatic activity within the kidney.

Role of mitochondrial-derived oxidants in renal tubular cell cold-storage injury.

Cold storage (CS) is regarded as a necessary procedure during donation of a deceased-donor kidney that helps to optimize organ viability. Increased oxidant generation during CS as well as during the reperfusion (or rewarming/CS.RW) phase has been suggested to be a major contributor to renal injury, although the source of and/or biochemical pathways involved in oxidant production remain unclear.

Infiltrating CD11b+CD11c+ cells have the potential to mediate inducible nitric oxide synthase-dependent cell death in mammary carcinomas of HER-2/neu transgenic mice.

The development of autochtonous mammary tumors in HER-2/neu transgenic mice is facilitated by immune tolerance to the neu-transgene. However, appropriate vaccination strategies can initiate immune system-mediated antitumor response by a process that requires IFN-gamma. We investigated the role of inducible nitric oxide synthase (iNOS) induction by IFN-gamma to promote tumor cell apoptosis.

Precision-cut slice cultures of tumors from MMTV-neu mice for the study of the ex vivo response to cytokines and cytotoxic drugs.

Ex vivo analysis of signaling pathways operating in tumor tissue is complicated by the three-dimensional structure, in particular by stroma-epithelial interactions. Studies performed with pure populations of tumor cells usually do not take into account this issue. One possibility to preserve the tissue architecture is the use of tumor slices.

CCR7-CCL19/CCL21-regulated dendritic cells are responsible for effectiveness of sublingual vaccination.

Our previous studies demonstrated the potential of the sublingual (s.l.) route for delivering vaccines capable of inducing mucosal as well as systemic immune responses.