Kaiyin Wu

Combined C3b and factor B autoantibodies and MPGN type II.

This letter describes two unrelated patients with membranoproliferative glomerulonephritis type 2 and autoantibodies to the two individual components of C3 convertase, factor B and C3. These autoantibodies enhance C3 convertase activity, probably leading to nephritis.

Tumor-Produced Versican V1 Enhances hCAP18/LL-37 Expression in Macrophages through Activation of TLR2 and Vitamin D3 Signaling to Promote Ovarian Cancer Progression In Vitro

Tumor-associated macrophages have been shown to promote tumor growth. They may have an obligatory function in angiogenesis, invasion, and metastasis through release of inflammatory mediators. Their presence in ovarian cancer has been correlated with poor prognosis in these patients. The human cationic antimicrobial protein-18 (hCAP18)/LL-37 was originally identified as an effector molecule of the innate immune system. It is released by innate immune cells, such as macrophages, to combat microorganisms. Previous studies have characterized the hCAP18/LL-37 as a growth factor that has been shown to promote ovarian tumor progression. However, the role hCAP18/LL-37 has in macrophage-promoted ovarian tumor development and how its expression is controlled in this context remains poorly understood. Here, we demonstrate in co-culture experiments of macrophages and ovarian cancer cells a significant increase in the in vitro proliferation and invasiveness of the tumor cells is observed. These enhanced growth and invasion properties correlated with hCAP18/LL-37 induction. HCAP18/LL-37 expression was diminished by addition of two neutralizing antibodies, TLR2 or TLR6, as well as Cyp27B1 or VDR inhibitors. Furthermore, either the TLR2 or TLR6 antibody reduced vitamin D3 signaling and tumor cell progression in vitro. Addition of Cyp27B1 or VDR inhibitors abrogated TLR2/6 activation-induced expression of hCAP18/LL-37 in macrophages. Knockdown of tumor-produced versican V1 by RNAi in these tumor cells led to a decreased induction of hCAP18/LL-37 in macrophages. Versican V1 knockdown also inhibited TLR2 and vitamin D3 signaling, as well as growth and invasiveness of these tumor cells in the in vitro co-culture. In summary, we have found that versican V1 enhances hCAP18/LL-37 expression in macrophages through activation of TLR2 and subsequent vitamin D-dependent mechanisms which promote ovarian tumor progression in vitro.

Recurrent Primary Focal Segmental Glomerulosclerosis Managed With Intensified Plasma Exchange and Concomitant Monitoring of Soluble Urokinase-Type Plasminogen Activator Receptor-Mediated Podocyte β3-integrin Activation.

Background Primary focal segmental glomerulosclerosis (FSGS) often causes nephrotic proteinuria and frequently results in end-stage renal disease and recurrence after kidney transplantation. Recent studies describe soluble urokinase-type plasminogen activator receptor (suPAR) as a circulating factor implicated in FSGS. Methods This single-center study included 12 adult patients with histologically proven primary FSGS (n = 2) or recurrent FSGS after transplantation (n = 10). The effect of plasma exchange (PE) on clinical outcome, suPAR levels, and in vitro podocyte &bgr;3-integrin activation was investigated over a median of 11 (6-18) sessions of PE. Results The course of treatment was monitored in a total of 70 sessions of PE, which partly eliminated suPAR, with a mean reduction of 37 ± 12% of serum concentration per session. However, a substantial rebound was observed between sessions, with suPAR levels reaching 99 ± 22% of the pretreatment levels after a median of 4 days. Podocyte &bgr;3-integrin activation dropped significantly after PE but rebounded within 4 days concomitant with a rising suPAR level. In 11 of 12 patients, multimodal treatment (including extensive PE) reduced proteinuria significantly (from 5.3 [2.0-7.8] to 1.0 [0.4-1.6] g/d), indicating clinical efficacy of the therapy. One patient suffered allograft loss due to FSGS recurrence. A persisting response was independent of a lasting reduction in the level of total suPAR because there was no sustained significant change in suPAR levels before and after the course of intensified treatment (3814 ± 908 to 3595 ± 521 pg/mL; P = 0.496). Conclusions We conclude that multimodal therapy including extensive PE was associated with stabilization of recurrent FSGS and a temporary lowering of plasma suPAR as well as podocyte &bgr;3-integrin activation. Whether a sustained lowering of total suPAR results in further improved outcomes requires additional study.

Identification of T Cell-Mediated Vascular Rejection After Kidney Transplantation by the Combined Measurement of 5 Specific MicroRNAs in Blood.

Background MicroRNAs (miRNAs, miR) hold important roles in the posttranscriptional regulation of gene expression. Their function has been correlated with kidney disease, and they might represent a new class of biomarkers for frequent evaluation of renal graft status. We analyzed their potential in identifying severe T cell–mediated vascular rejection (TCMVR) (Banff 4-II/III) in kidney transplanted patients. Methods Microarray experiments and semiquantitative real-time reverse transcription polymerase chain reaction were performed with total RNA isolated from blood cells of kidney graft recipients. Initial microarray analysis revealed 23 differentially expressed miRNAs distinguishing patients with TCMVR from patients with stable grafts. From these, we validated and further determined the expression of 6 differentially expressed miRNAs and 2 control miRNAs in 161 samples from patients with T cell–mediated rejection (Banff 3-Borderline, Banff 4-I/II/III), Banff-2 antibody-mediated rejection, Banff-5 interstitial fibrosis/tubular atrophy, in samples from stable patients and in samples from patients with urinary tract infection using real-time reverse transcription polymerase chain reaction. Results Expression levels of all 6 candidate miRNAs were significantly downregulated in blood of TCMVR patients compared to the other groups and displayed high sensitivities and specificities for diagnosing TCMVR. The combination of 5 miRNAs, identified by an unbiased multivariate logistic regression followed by cross-validation, enhanced the sensitivity and specificity for the diagnosis of TCMVR after renal transplantation. Conclusions The combined measurement of miRNA-15B, miRNA-16, miRNA-103A, miRNA-106A, and miRNA-107 may help to better identify TCMVR after renal transplantation in a precise and clinically applicable way.

Role of TRPV1 Channels in Ischemia/Reperfusion-Induced Acute Kidney Injury

Objectives Transient receptor potential vanilloid 1 (TRPV1) -positive sensory nerves are widely distributed in the kidney, suggesting that TRPV1-mediated action may participate in the regulation of renal function under pathophysiological conditions. Stimulation of TRPV1 channels protects against ischemia/reperfusion (I/R)-induced acute kidney injury (AKI). However, it is unknown whether inhibition of these channels is detrimental in AKI or not. We tested the role of TRPV1 channels in I/R-induced AKI by modulating these channels with capsaicin (TRPV1 agonist), capsazepine (TRPV1 antagonist) and using Trpv1−/− mice. Methods and Results Anesthetized C57BL/6 mice were subjected to 25 min of renal ischemia and 24 hrs of reperfusion. Mice were pretreated with capsaicin (0.3 mg/kg body weight) or capsazepine (50 mg/kg body weight). Capsaicin ameliorated the outcome of AKI, as measured by serum creatinine levels, tubular damage,neutrophil gelatinase-associated lipocalin (NGAL) abundance and Ly-6B.2 positive polymorphonuclear inflammatory cells in injured kidneys. Neither capsazepine nor deficiency of TRPV1 did deteriorate renal function or histology after AKI. Measurements of endovanilloids in kidney tissue indicate that 20-hydroxyeicosatetraeonic acid (20-HETE) or epoxyeicosatrienoic acids (EETs) are unlikely involved in the beneficial effects of capsaicin on I/R-induced AKI. Conclusions Activation of TRPV1 channels ameliorates I/R-induced AKI, but inhibition of these channels does not affect the outcome of AKI. Our results may have clinical implications for long-term safety of renal denervation to treat resistant hypertension in man, with respect to the function of primary sensory nerves in the response of the kidney to ischemic stimuli.

Neuroprotection against permanent focal cerebral ischemia by ginkgolides A and B is associated with obstruction of the mitochondrial apoptotic pathway via inhibition of c-Jun N-terminal kinase in rats

We have previously reported that ginkgolides containing ginkgolides A and B (GKAB) reduce infarct size in a rat model of focal ischemia. c‐Jun N‐terminal kinase (JNK), also known as stress‐activated kinase (SAPK), is a critical stress‐responsive kinase activated by various brain insults. Previous studies have demonstrated a brief increase in p‐SAPK/JNK levels after focal ischemic brain injuries. In this study, we sought to investigate whether the neuroprotective effects of GKAB in rat models of permanent focal cerebral ischemia are associated with the JNK signaling pathway. Sprague‐Dawley rats were subjected to permanent middle cerebral artery occlusion by intraluminal suture blockade. GKAB was injected intravenously immediately after ischemia onset. Here we demonstrate in rats that GKAB reduces neuronal apoptosis and blocks the increase of p‐SAPK/JNK levels and nuclear translocation after cerebral ischemia in a dose‐dependent manner. Furthermore, we report that cerebral ischemia increases ischemia‐induced induction of reactive oxygen species, and this effect was blocked by GKAB. In addition, we show that BimL is induced and attenuated by GKAB. GKAB also repressed the ischemia‐induced increase in the expression of Bax and reversed the decline in expression of Bcl‐2. Likewise, there was a reduction in the release or activation of several mitochondrial proapoptotic molecules, including cytochrome c, caspases 3 and 9, and PARP. Taken together, our findings strongly suggest that GKAB‐mediated neuroprotective effects against focal ischemia act through the inhibition of p‐SAPK/JNK activation, in which the obstruction of the mitochondrial apoptotic pathway via the JNK signaling pathway is a key downstream mechanism of GKAB.

Renal Ischemia/Reperfusion Injury in Soluble Epoxide Hydrolase-Deficient Mice

Aim 20-hydroxyeicosatetraenoic acid (20-HETE) and epoxyeicosatrienoic acids (EETs) are cytochrome P450 (CYP)-dependent eicosanoids that play opposite roles in the regulation of vascular tone, inflammation, and apoptosis. 20-HETE aggravates, whereas EETs ameliorate ischemia/reperfusion (I/R)-induced organ damage. EETs are rapidly metabolized to dihydroxyeicosatrienoic acids (DHETs) by the soluble epoxide hydrolase (sEH). We hypothesized that sEH gene (EPHX2) deletion would increase endogenous EET levels and thereby protect against I/R-induced acute kidney injury (AKI). Methods Kidney damage was evaluated in male wildtype (WT) and sEH-knockout (KO)-mice that underwent 22-min renal ischemia followed by two days of reperfusion. CYP-eicosanoids were analyzed by liquid chromatography tandem mass spectrometry. Results Contrary to our initial hypothesis, renal function declined more severely in sEH-KO mice as indicated by higher serum creatinine and urea levels. The sEH-KO-mice also featured stronger tubular lesion scores, tubular apoptosis, and inflammatory cell infiltration. Plasma and renal EET/DHET-ratios were higher in sEH-KO than WT mice, thus confirming the expected metabolic consequences of sEH deficiency. However, CYP-eicosanoid profiling also revealed that renal, but not plasma and hepatic, 20-HETE levels were significantly increased in sEH-KO compared to WT mice. In line with this finding, renal expression of Cyp4a12a, the murine 20-HETE-generating CYP-enzyme, was up-regulated both at the mRNA and protein level, and Cyp4a12a immunostaining was more intense in the renal arterioles of sEH-KO compared with WT mice. Conclusion These results indicate that the potential beneficial effects of reducing EET degradation were obliterated by a thus far unknown mechanism leading to kidney-specific up-regulation of 20-HETE formation in sEH-KO-mice.

Clinical Outcome of Patients with De Novo C1q-Binding Donor-Specific HLA Antibodies after Renal Transplantation.

Background De novo donor specific anti-HLA antibodies (dnDSA) may cause graft loss in renal transplant recipients. The capability to bind the complement may help to stratify the risk for inferior outcomes associated with dnDSA. We developed a modified C1q-binding assay and hypothesized that C1q-binding dnDSA could differentiate between indolent and harmful dnDSA causing antibody-mediated rejection (AMR) and graft loss. Methods We retrospectively identified 59 renal transplant recipients who developed dnDSA and had serum available and complete follow-up. All patients were analyzed for C1q-binding dnDSA at the time of dnDSA detection, and 1-year later or at time of AMR. AMR-positive patients were also tested 6 to 12 months before the event if IgG dnDSA was present. Results Thirty-seven of 59 dnDSA+ patients developed AMR during 5.9 ± 3.1 years follow-up. AMR-positive patients had more dnDSA with a significant higher frequency of class I, a higher frequency and a higher mean fluorescence intensity value of C1q+-dnDSA at all time-points. Death-censored AMR-free and allograft survivals were significantly lower in C1q+-dnDSA patients. In multivariate analysis, C1q+-dnDSA was an independent risk factor for AMR. Conclusions C1q-binding dnDSA is associated with inferior outcomes, yet not in all patients. Nevertheless, C1q+-dnDSA was shown to be an independent risk factor of AMR and graft loss and may be a useful tool to stratify the immunological risk for AMR.

Rituximab in Combination With Bortezomib, Plasmapheresis, and High-Dose IVIG to Treat Antibody-Mediated Renal Allograft Rejection

Background Current treatment strategies for antibody-mediated renal allograft rejection (AMR) are not sufficiently effective. In most centers, “standard of care” treatment includes plasmapheresis (PPH) and IVIG preparations. Since several years, modern therapeutics targeting B cells and plasma cells have become available. We investigated, whether combined administration of rituximab and bortezomib in addition to PPH and high-dose IVIG is useful. Methods Between November 2011 and January 2013, we treated 10 consecutive patients with biopsy-proven AMR with rituximab (500 mg), bortezomib (4× 1.3 mg/m2), PPH (6×), and high-dose IVIG (1.5 g/kg) (group A). This group was compared with a group of 11 consecutive patients treated with an identical regimen without rituximab between July 2010 and November 2011 (group B). Results Median follow-up was 41(33-46) months in group A and 55(47-63) months in group B. At 40 months after treatment, graft survival was 60% in group A and 64% in group B, respectively (P = 0.87). Before and after treatment, serum creatinine, estimated glomerular filtration rate, and proteinuria were not different between groups. A significant reduction in donor-specific HLA antibody mean fluorescence intensity was observed in group A (25.2%, P = 0.046) and B (38.3%, P = 0.01) at 3 months posttreatment. In group A, more patients suffered from side effects compared with group B (infections: 70% vs 18%, P = 0.02). Conclusions The addition of rituximab to bortezomib, PPH, and high-dose IVIG did not further improve graft survival. Instead, we observed an increase of side effects. Therefore, combined administration of bortezomib and rituximab in addition to PPH and IVIG should be regarded with caution.

The Relationship of the Severity and Category of Acute Rejection With Intimal Arteritis Defined in Banff Classification to Clinical Outcomes.

Background It is unclear if the category of acute rejection with intimal arteritis (ARV) is relevant to short- and long-term clinical outcomes and if the graft outcomes are affected by the severity of intimal arteritis. Methods One hundred forty-eight ARV episodes were reviewed and categorized according to the 2013 Banff criteria of AMR: T cell–mediated rejection with intimal arteritis (v) lesion (TCMRV; n = 78), total antibody-mediated rejection with v lesion (AMRV), which were further divided into suspicious AMRV (n = 37) and AMRV (n = 33). The Banff scores of intimal arteritis (v1, v2 and v3) represented low, moderate, and high ARV severity. Results The grafts with TCMRV, suspicious AMRV (sAMRV), and AMRV showed similar responses to antirejection therapy, whereas the grafts with v2- or v3-ARV responded significantly poorer compared to those with v1-ARV. The 8-year death-censored graft survival (DCGS) rate was 56.8% of TCMRV versus 34.1% of total AMRV (Log rank, P = 0.03), but the 1- and 5-year DCGS rates were comparable between the 2 groups; moreover, the 1-, 5-, and 8-year DCGS rates of v1-ARV were evidently higher than v2- and v3-ARV (each pairwise comparison to v1-AVR yields P < 0.01); in contrast, the DCGS rates were similar between sAMRV and AMRV. The existing donor-specific antibodies or moderate microvascular inflammation or C4d-positive staining or intensive tubulointerstitial inflammation played a less significant role on the long-term graft survival. Conclusions Compared to the category, the ARV severity is more closely associated with the initial response to antirejection therapy and long-term graft failure. The sAMRV and AMRV might represent a spectrum of the same disorder.