Acute kidney injury (AKI) caused by ischemia reperfusion is a major clinical problem in both native and transplanted kidneys. We previously showed that deficiency of Nrf2, a potent bZIP transcription factor that binds to the antioxidant response element, enhances susceptibility to experimental ischemic AKI. Here we further explored the role of Nrf2 in AKI by amplifying Nrf2 activation in vivo and in vitro with the synthetic triterpenoid CDDO-imidazolide. Mice treated with CDDO-imidazolide and undergoing experimental bilateral ischemic AKI had improved survival and renal function. Treated mice had improved renal histology with a decrease in tubular injury, as well as a decrease in pro-inflammatory cytokine and chemokine production compared to vehicle-treated mice. In an exploration of protective mechanisms, we found an up-regulation of Nrf2 target antioxidant genes in CDDO-imidazolide treated mouse kidneys. Furthermore, Nrf2 deficient mice treated with CDDO-imidazolide had no significant improvement in mortality, renal function or histology, pro-inflammatory cytokine gene expression, and no significant increase in antioxidant gene expression. In vitro studies demonstrated that the renal epithelial cells were likely an important target of CDDO-imidazolide. Thus, activation of Nrf2 signaling with CDDO-imidazolide confers protection from AKI, and presents a new therapeutic opportunity for this common and serious condition.

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Nanoparticles have garnered widespread interest for both the imaging and treatment of cancer due to their unique and tunable pharmacokinetics and their ability to carry a high payload of diverse compounds. However, despite these favorable attributes, the extent of tumor accumulation can be severely restricted due to the dense stroma surrounding the often-permeable blood vessel wall and high intratumoral pressure. In this study, we investigated whether modifying the surface of pegylated gold nanoparticles (AuNPs) with collagenase could improve the accumulation of nanoparticles within a murine tumor xenograft. It was determined that collagenase remains active after surface conjugation and the presence of collagenase has no measureable effect on cell proliferation in vitro. Following intravenous injection, the largest fractions of collagenase-labeled AuNPs were found in the liver and spleen. Histological analysis revealed no signs of toxicity in either of these organs. Blood chemistry revealed normal levels of liver enzymes, but a slightly elevated level of total bilirubin. Within the tumor, AuNPs labeled with collagenase exhibited a 35% increase in accumulation compared with unlabeled AuNPs. Therefore, these studies provide preliminary evidence that the functionalization of nanoparticles with collagenase represent an effective and safe approach to improve tumor accumulation.

Inflammation contributes to the pathogenesis of ischemic acute kidney injury (AKI), and T cells mediate the early phase of ischemia-reperfusion injury (IRI). The Fas/Fas ligand (FasL) pathway modulates the balance of T cell subsets in the peripheral circulation as well as multiple inflammatory responses, suggesting that FasL may mediate ischemic AKI. Here, we induced bilateral renal IRI in mice bearing a loss-of-function mutation of FasL (the gld mutation) and in wild-type mice. Compared with wild-type mice, serum creatinine was lower in gld mice (1.4 Ϯ 0.9 mg/dl versus 2.6 Ϯ 0.4) at 24 hours after IRI (P Ͻ 0.05). In addition, gld mice had fewer TNF-␣-producing T lymphocytes in the kidneys and renal lymph nodes. Furthermore, pharmacologic blockade of FasL protected the kidneys of wild-type mice from IRI. Analysis of bone marrow chimeric mice suggested that the pathogenic effect of FasL involves leukocytes; reconstitution of wild-type mice with gld splenocytes attenuated IRI. In contrast, reconstitution of gld mice with wild-type splenocytes enhanced IRI. These data demonstrate that FasL, particularly on leukocytes, mediates ischemic AKI.

Long-circulating gold nanoparticles (AuNPs) have garnered a great deal of interest as both imaging and therapeutic agents. However, their protracted elimination and long-term persistence within many organ systems remains a concern for clinical translation. To improve the excretion of long-circulating nanoparticles, we prepared ~80 nm biodegradable polymeric micelles with 0.9 nm or 5 nm AuNPs tightly packed within the hydrophobic core. These gold-loaded polymeric micelles (GPMs) were expected to allow for improved excretion of gold, compared with single large AuNPs, owing to the smaller size and larger surface-to-volume ratio of the individual AuNPs within the micelle. Following intravenous administration of GPMs, organs were harvested and examined for gold content using inductively coupled plasma optical emission spectrometry (ICP-OES) for up to 3 months post-injection. While both GPM formulations showed significant clearance of gold over time, micelles containing 0.9 nm AuNPs showed a 72% and 67% reduction in gold content in the liver and spleen, respectively, between 1 day and 3 months post-injection, compared with a 38% and 35% reduction in mice receiving 5 nm GPMs. Furthermore, feces and urine analysis revealed approximately 7.5 and 100 times more gold, respectively, in mice that received 0.9 nm GPMs one day after injection. These findings suggest that the excretion profile of inorganic nanomaterials may be improved if clusters of small inorganic materials are used in favor of single solid particles.

Because of their low membrane permeability the use of polymeric vesicles in certain drug delivery and molecular imaging applications and as bioreactors is less than ideal. Here, we report a simple method to prepare porous polymeric vesicles that possess high membrane permeability. Specifically, porous vesicles were produced from the aqueous assembly of the diblock copolymer PEG-PBD, and the triblock copolymer PEG-PPO-PEG. It was found that PEG-PPO-PEG-doped polymersomes exhibited improved membrane permeability to molecules less than 5 kDa. Further, these porous vesicles retained molecules ≥10 kDa within their aqueous interiors with no significant leakage. To demonstrate its application, highly efficient magnetic resonance contrast agents were produced from porous polymersomes by encapsulating macromolecules labeled with gadolinium. Due to a fast water exchange rate with surrounding bulk water, these paramagnetic porous polymersomes exhibited higher r1 relaxivity compared with Gd-encapsulated vesicles with no pores. Due to their simplicity, the porous polymersomes prepared with this method are expected to have additional useful applications.

Although T cells have been shown to play a direct role in kidney ischemia-reperfusion injury (IRI), little is known about the underlying mechanisms. We hypothesized that studying the transcriptional responses in kidney-infiltrating T cells would help elucidate novel therapeutic targets for kidney IRI. Unilateral renal pedicle clamping for 45 min was performed in male C57BL/6 mice, and CD3(+) T cells were isolated from the kidney and purified. Transcriptional activities of T cell were measured by array-based PCR compared between ischemic kidneys and contralateral nonischemic kidneys. Among total of 89 genes analyzed, 24, 22, 24, and 37 genes were significantly changed at 6 h, day 3, day 10, and day 28 after IRI. Genes associated with cytokines, chemokines, and costimulatory molecules were upregulated. Pathway analysis identified CC motif chemokine receptor 5 (CCR5) as a candidate pathophysiological pathway. CCR5 upregulation was validated at the protein level, and CCR5 blockade improved renal function after kidney IRI. Using discovery techniques to identify transcriptional responses in purified kidney-infiltrating cells enabled the elucidation of novel mechanisms and therapeutic targets for IRI.

Copper(II) hydroxide reacts with 2,2Ј-bipyridine (bipy) and sodium pyrophosphate in a 2:2:1 stoichiometric ratio under ambient conditions at pH 1.6 in water. The resulting neutral dinuclear Cu II complex features a bridging set containing bridging monoprotonated pyrophosphate and a monoatomic chloro bridge (making this the first pyrophosphate bridged coordination complex containing an alternate, additional halide bridge between the metal centers). Single-crystal X-ray diffraction studies revealed the complex to be {[Cu(bipy)] 2 (µ-HP 2 O 7 )(µ-Cl)}·H 2 O. The structure consists of a dimeric copper(II) system with each metal ion in a square pyramidal geometry. The asymmetric [Cu(bipy)] 2+ units are bridged by bis-bidentate pyrophosphate and an axially bridging chlorine atom. The incorporation of an additional bridge (halide) and the presence of protonated pyrophosphate (HP 2 O 7 3-) in the structure are both rare for this family of structures. Inter-