Progranulin deficiency attenuates tubulointerstitial injury in a mouse unilateral ureteral obstruction model.

Progranulin (PGRN) may have two opposing effects-inflammation and anti-inflammation-in different diseases. Although previous studies have reported that PGRN is involved in liver fibrosis, its involvement in tubulointerstitial fibrosis remains to be fully elucidated. Herein, we investigated these issues using PGRN-knockout (KO) mice treated with unilateral ureteral obstruction (UUO). Eight-week-old male PGRN-KO and wild-type (WT) mice were euthanized 3 and 7 days following UUO, and their kidneys were harvested for histopathological analysis. The renal expression of PGRN was evaluated by immunohistochemical and/or western blot analyses. The renal mRNA levels of markers related to inflammation (Il1b, Tnf, Il6, Ccl2, and Adgre1) and fibrosis (Tgfb1, Acta2, Fn1, and Col1a2) were evaluated using quantitative PCR. Histological changes such as renal tubular atrophy, urinary casts, and tubulointerstitial fibrosis were significantly improved in UUO-KO mice compared with UUO-WT mice. Quantitative PCR revealed that the mRNA expression levels of all inflammation- and fibrosis-related markers were lower in UUO-KO mice than in UUO-WT mice at 3 and/or 7 days after UUO. Moreover, PGRN and GRN protein levels were higher in the kidneys of UUO-WT mice than in mice that did not undergo UUO. Elevated GRN levels associated with excess PGRN levels may be involved in the occurrence of renal inflammation and fibrosis in UUO mice.

Progranulin and Its Receptor Predict Kidney Function Decline in Patients With Type 2 Diabetes.

Progranulin (PGRN), a growth factor, is abundantly expressed in a broad range of tissues and cell types with pleiotropic functions including inflammation, neurodegeneration, and facilitating lysosome acidification. PGRN binds to TNF receptors (TNFR) and inhibits downstream inflammatory signaling pathways. TNFR is a well-known predictor of glomerular filtration rate (GFR) decline in a variety of diseases. Therefore, we measured circulating PGRN in addition to TNFR using an enzyme-linked immunosorbent assay and explored whether it predicted renal prognosis in 201 Japanese patients with type 2 diabetes. During a median follow-up of 7.6 years, 21 participants reached primary renal endpoint, which involves a decline of at least 57% in eGFR from baseline, or the onset of end-stage renal disease. Univariate Cox regression analysis revealed that classical renal measures (GFR and albuminuria), two TNF-related biomarkers (PGRN and TNFR), and BMI were associated with this outcome. Multivariate analysis demonstrated that high levels of PGRN [HR 2.50 (95%CI 2.47-2.52)] or TNFR1 [HR 5.38 (95%CI 5.26-5.50)] were associated with this outcome after adjusting for relevant covariates. The high levels of PGRN as well as TNFR1 were associated with a risk of primary renal outcome in patients with type 2 diabetes after adjusting for established risk factors.

Differential organ-specific inflammatory response to progranulin in high-fat diet-fed mice.

Progranulin (PGRN) has been reported to bind tumor necrosis factor (TNF) receptor and to inhibit TNFα signaling. We evaluated the effect of augmentation of TNFα signaling by PGRN deficiency on the progression of kidney injury. Eight-week-old PGRN knockout (KO) and wild-type (WT) mice were fed a standard diet or high-fat diet (HFD) for 12 weeks. Albuminuria, markers of tubular damage, and renal mRNA levels of inflammatory cytokines were higher in HFD-fed KO (KO-HFD) mice than in HFD-fed WT (WT-HFD) mice. Body weight, vacuolization in proximal tubules, and systemic and adipose tissue inflammatory markers were lower in the KO-HFD mice than in the WT-HFD mice. The renal megalin expression was lower in the KO mice than in the WT mice regardless of the diet type. The megalin expression was also reduced in mouse proximal tubule epithelial cells stimulated with TNFα and in those with PGRN knockdown by small interfering RNA in vitro. PGRN deficiency was associated with both exacerbated renal inflammation and decreased systemic inflammation, including that in the adipose tissue of mice with HFD-induced obesity. Improved tubular vacuolization in the KO-HFD mice might partially be explained by the decreased expression of megalin in proximal tubules.

Fractional excretion of tumor necrosis factor receptor 1 and 2 in patients with type 2 diabetes and normal renal function.

AIMS/INTRODUCTION: Increased concentrations of serum tumor necrosis factor (TNF) receptors (TNFRs; TNFR1 and TNFR2) are positively associated with the urinary albumin-to-creatinine ratio (ACR), and negatively associated with the estimated glomerular filtration rate (eGFR) in patients with type 2 diabetes. However, the mechanism underlying this increase and the relationship between TNFRs in serum, and urine and kidney measures (ACR and eGFR) are unclear. MATERIALS AND METHODS: This was a cross-sectional study that included 499 patients with type 2 diabetes and eGFR ≥60 mL/min/1.73 m2 . The concentrations of TNFRs in serum and urine, and their respective fractional excretion, were measured. RESULTS: Serum and urinary TNFR levels were positively associated with the ACR, and negatively associated with the eGFR. The fractional excretion of TNFRs did not differ between patients with an eGFR ≥90 and those with an eGFR 60-89 mL/min/1.73 m2 , and also did not correlate with eGFR. After adjustment for relevant covariates, the serum TNFRs were associated with a lower eGFR (60-89 mL/min/1.73 m2 ) and an increased ACR (≥30 mg/gCr), but urinary TNFRs were associated with an increased ACR (≥30 mg/gCr) alone, in the multivariate logistic model. CONCLUSIONS: The pattern of fractional excretion TNFRs showed that an increase in serum TNFRs might result from their increased systemic production, including in the kidney, rather than being a simple reflection of GFR decline. Kidney measures appear to be strongly associated with serum TNFRs rather than urinary TNFRs in patients with type 2 diabetes and normal renal function.

The sodium-glucose cotransporter 2 inhibitor tofogliflozin prevents diabetic kidney disease progression in type 2 diabetic mice.

Trials on cardiovascular and renal outcomes in patients with type 2 diabetes have consistently demonstrated that sodium-glucose cotransporter 2 (SGLT2) inhibitors reduce the risk of diabetic kidney disease (DKD) progression. However, their renal protective mechanisms have yet to be completely understood and the effect on albuminuria reduction in animal models is controversial. We investigated these issues using KK and KK-Ay mice as a control (CTRL) and as a model for type 2 diabetes (DKD), respectively. KK-Ay mice were treated with 0.015% tofogliflozin, which is an SGLT2 inhibitor, starting at seven weeks of age for eight weeks. Compared with the CTRL mice, the DKD mice had higher HbA1c levels and albuminuria. Although tofogliflozin treatment significantly lowered HbA1c levels, it did not reverse albuminuria. Tofogliflozin treatment enhanced damage in both the glomerular (i.e., enlarged mesangial area, increased foot process effacement rate, and decreased number of WT-1-positive cells) and tubulointerstitial (increased protein levels of KIM-1 and MCP-1, increased number of macrophages, and abnormal mitochondrial morphology) areas. Our results suggest that tofogliflozin may prevent glomerular and tubulointerstitial damage, partly by ameliorating hyperglycemia, renal inflammation, and abnormal mitochondrial morphology.

Aspartic acid supplementation ameliorates symptoms of diabetic kidney disease in mice.

Diabetic kidney disease (DKD) is among the most common and serious complications of both type 1 and type 2 diabetes. In this study, we used KK/Ta-Ins2Akita (KK-Akita) mice as a model of DKD and KK/Ta (KK) mice as controls to identify novel factors related to the development/progression of DKD. Capillary electrophoresis coupled with mass spectrometry analysis revealed that circulating Asp (l-aspartic acid) levels in diabetic KK-Akita mice tend to be lower than those in control KK mice. Therefore, we evaluated the effect of Asp supplementation to prevent the progression of DKD in KK-Akita mice. Mice were divided into three groups: (a) untreated KK mice (Control group), (b) untreated KK-Akita mice (DKD group), and (c) treated (double-volume Asp diet) KK-Akita mice (Tx group). Kidney sections were stained with fluorescein isothiocyanate-labeled lectins, wheat germ agglutinin (WGA), and anti-endothelial nitric oxide synthase (eNOS) antibody for evaluation of endothelial surface layer (ESL) and NO synthesis. The mesangial area and glomerular size in the DKD group were significantly larger than those in the Control group; however, there was no significant difference in those between the DKD and Tx groups. Albuminuria, the ratio of foot process effacement, and thickness of glomerular basement membrane in the Tx group were significantly lower than those in the DKD group. Furthermore, the expression levels of glomerular WGA and microvascular eNOS in the Tx group improved significantly and approached the level in the Control group. In conclusion, the improvement of albuminuria in the Tx group may be caused by the reduction of oxidative stress in the kidneys, which may lead to the subsequent improvement of glomerular ESL.

Circulating kidney injury molecule-1 as a biomarker of renal parameters in diabetic kidney disease.

AIMS/INTRODUCTION: Urinary kidney injury molecule-1 (KIM-1) has been associated with proximal tubular damage in human and animal studies. Although it has been recognized as a biomarker of acute kidney injury and chronic kidney disease, its significance in the serum remains unclear. Therefore, we examined the relationship of serum and urinary KIM-1 levels with renal parameters in patients with type 2 diabetes. MATERIALS AND METHODS: Serum and urinary KIM-1 levels, together with urinary liver-type fatty acid-binding protein, were measured in 602 patients with type 2 diabetes and an estimated glomerular filtration rate (eGFR) ≥30 mL/min/1.73 m2 . These were then compared with the urinary albumin-to-creatinine ratio and eGFR. RESULTS: The serum and urinary KIM-1 levels were significantly different among the three (eGFR ≥60, 45-59, <45 mL/min/1.73 m2 ) groups. These levels were positively associated with the albumin-to-creatinine ratio and negatively associated with eGFR. In a multivariate logistic model, both serum and urinary KIM-1 were associated with an increased albumin-to-creatinine ratio (>30 mg/g Cr), but only the serum KIM-1 was associated with a lower eGFR (<60 mL/min/1.73 m2 ), after adjustment for covariates. CONCLUSIONS: Renal parameters appear to be strongly associated with serum KIM-1, and not urinary KIM-1, in patients with type 2 diabetes and an eGFR ≥30 mL/min/1.73 m2 .

Different growth and metastatic phenotypes associated with a cell-intrinsic change of Met in metastatic melanoma.

A dynamic phenotypic change contributes to the metastatic progression and drug resistance in malignant melanoma. Nevertheless, mechanisms for a phenotypic change have remained to be addressed. Here, we show that Met receptor expression changes in a cell-autonomous manner and can distinguish phenotypical differences in growth, as well as in metastatic and drug-resistant characteristics. In metastatic melanoma, the cells are composed of Met-low and Met-high populations. Met-low populations have stem-like gene expression profiles, are resistant to chemotherapeutic agents, and have shown abundant angiogenesis and rapid tumor growth in subcutaneous inoculation. Met-high populations have a differentiated phenotype, are relatively resistant to B-RAF inhibitor, and are highly metastatic to the lungs. Met plays a definitive role in lung metastasis because the lung metastasis of Met-high cells requires Met, and treatment of mice with the Met-containing exosomes from Met-high cells facilitates lung metastasis by Met-low cells. Clonal cell fate analysis showed the hierarchical phenotypical changes from Met-low to Met-high populations. Met-low cells either showed self-renewal or changed into Met-high cells, whereas Met-high cells remained Met-high. Clonal transition from Met-low to Met-high cells accompanied changes in the gene expression profile, in tumor growth, and in metastasis that were similar to those in Met-high cells. These findings indicate that malignant melanoma has the ability to undergo phenotypic change by a cell-intrinsic/autonomous mechanism that can be characterized by Met expression.

Pharmacokinetics and pharmacodynamics following intravenous administration of recombinant human hepatocyte growth factor in rats with renal injury.

BACKGROUND/AIM: Hepatocyte growth factor (HGF) plays a role in the regeneration and protection of the kidney, but little information is available concerning the pharmacokinetics of therapeutic treatment with HGF. In this study, HGF was administered after the onset of renal injury, and pharmacokinetic analysis was performed simultaneously with an efficacious dose. METHODS: For the study of pharmacodynamics, recombinant human HGF was intravenously administered to rats with glycerol-induced acute kidney injury (AKI). In the pharmacokinetic study, rats subjected to glycerol injection or renal ischemia-reperfusion were used as models of AKI, and rats subjected to 5/6 nephrectomy were used as models of chronic kidney disease (CKD). RESULTS: After intravenous administration of HGF at doses of 0.5-2.0 mg/kg, the elevation of blood urea nitrogen was suppressed, indicating that HGF had a pharmacodynamic effect. However, no significant difference was seen in the pharmacokinetic parameters such as clearance, distribution volume and half-life between the normal, AKI and CKD groups. CONCLUSION: The intravenous administration of HGF after the onset of renal dysfunction exerted a pharmacological effect on AKI, and renal injury did not affect the clearance of plasma HGF. This unaffected profile may serve as a base for the safety of HGF during therapeutic administration.

Sense transgene-induced post-transcriptional gene silencing in tobacco compromises the splicing of endogenous counterpart genes.

Sense transgene-induced post-transcriptional gene silencing (S-PTGS) is thought to be a type of RNA silencing in which ARGONAUTE1 directs the small interfering RNA (siRNA)-mediated cleavage of a target mRNA in the cytoplasm. Here, we report that the altered splicing of endogenous counterpart genes is a main cause for the reduction of their mature mRNA levels. After the S-PTGS of a tobacco endoplasmic reticulum ω-3 fatty acid desaturase (NtFAD3) gene, 3'-truncated, polyadenylated endo-NtFAD3 transcripts and 5'-truncated, intron-containing endo-NtFAD3 transcripts were detected in the total RNA fraction. Although transcription proceeded until the last exon of the endogenous NtFAD3 gene, intron-containing NtFAD3 transcripts accumulated in the nucleus of the S-PTGS plants. Several intron-containing NtFAD3 transcripts harboring most of the exon sequences were generated when an endogenous silencing suppressor gene, rgs-CaM, was overexpressed in the S-PTGS plants. These intron-containing NtFAD3 splice variants were generated in the presence of NtFAD3 siRNAs that are homologous to the nucleotide sequences of these splice variants. The results of this study indicate that the inhibition of endo-NtFAD3 gene expression is primarily directed via the alteration of splicing and not by cytoplasmic slicer activity. Our results suggest that the transgene and intron-containing endogenous counterpart genes are differentially suppressed in S-PTGS plants.

Feasibility of intraoperative radiation therapy for early breast cancer in Japan: a single-center pilot study and literature review.

BACKGROUND: Intraoperative radiation therapy (IORT) is under evaluation in breast-conserving surgery because the feasibility of the IORT procedure including transportation of the patient under general anesthesia is not well established. Thus, this prospective single-center study aimed to test the feasibility of IORT at a single dose of 21 Gy in Japanese breast cancer patients. METHODS: The primary endpoint was early toxicity; the secondary endpoint was late toxicity. Patients with histologically or cytologically proven primary early breast cancer were eligible. Inclusion criteria were as follows: (1) T < 2.5 cm; (2) desire for breast-conserving surgery; (3) age >50 years; (4) surgical margin >1 cm; (5) intraoperative pathologically free margins; and (6) sentinel node negative. Exclusion criteria were (1) contraindications to radiation therapy; (2) past radiation therapy for the same breast or chest; (3) extensive intraductal component; and (4) a tumor located in the axillary tail of the breast. All patients gave written informed consent. Partial resection was performed with at least a margin of 1 cm around the tumor. The patient was transported from the surgical suite to the radiation room. Radiation (Clinac(®) 21EX, Varian Medical Systems, Inc.) at 21 Gy was delivered directly to the mammary gland. Toxicity was evaluated with the Common Terminology Criteria for Adverse Events V4.0. RESULTS: Five patients were enrolled in this pilot study and received 21 Gy. Follow-up ranged from 7.8 to 11.0 months (median 10.2). Intraoperative transportation to the radiation room during the surgical procedure under general anesthesia was performed safely in all patients. Treatment-related toxicities within 3 months were deep connective tissue fibrosis (grade 1, n = 3) and pain (grade 1, n = 3). There was no case of wound infection, wound dehiscence, or soft tissue necrosis. Overall, there was no severe adverse event. CONCLUSIONS: The procedure was tolerated very well in this first group of Japanese female patients treated with IORT, as was the case with European women. A longer follow-up is needed for the evaluation of any potential late side effects or recurrences. A phase II study is now being conducted for the next group of patients (UMIN000003578).

α-Lipoic acid-induced inhibition of proliferation and met phosphorylation in human non-small cell lung cancer cells.

α-Lipoic acid (α-LA), a naturally occurring anti-oxidant and co-factor for metabolic enzymes, suppresses the growth of different types of tumor cells. The mechanisms that are responsible for these results, however, remain to be elucidated. In the present study, we investigated the effects of α-LA on the proliferation and activation status of definitive receptor tyrosine kinases, epidermal growth factor receptor (EGFR) and Met/hepatocyte growth factor (HGF) receptor, in gefitinib-sensitive human non-small cell lung cancer cells harboring EGFRs with an activating mutation. The enantiomers R-α-LA and S-α-LA suppressed cell proliferation and increased the level of reactive oxygen species in HCC-827 and PC-9 human non-small cell lung cancer cells in an indistinguishable dose-dependent fashion. A phospho-receptor tyrosine kinase array and cell cycle analysis indicated that α-LA decreased tyrosine phosphorylation levels of EGFR, ErbB2, and Met, and this was associated with an inhibition in the cell-cycle transition from the G1 phase to the S phase without inducing apoptosis. Gefitinib, an inhibitor for EGFR tyrosine kinase, inhibited EGFR tyrosine phosphorylation/activation and proliferation of the cells. Instead, the addition of HGF induced Met tyrosine phosphorylation, and this was associated with a resistance to gefitinib-induced growth inhibition, which meant a gain in proliferative ability. In the presence of gefitinib and HGF, the addition of α-LA suppressed Met tyrosine phosphorylation, and this was associated with an inhibition in cell growth. These results suggest that the suppression of tyrosine phosphorylation/activation of growth factor receptors that is critical for the proliferation of human non-small cell lung cancer cells is a mechanism by which α-LA exerts growth inhibition for cancer cells.

High recurrence risk and use of adjuvant trastuzumab in patients with small, HER2-positive, node-negative breast cancers.

BACKGROUND: Five randomized trials of adjuvant trastuzumab have reported significant improvements in recurrence-free survival (RFS) and overall survival. However, patients with node-negative tumors 1 cm or smaller were excluded from these trials. We assessed the recurrence risk and benefit of adjuvant therapy in such patients with small tumors. METHODS: We identified patients with node-negative breast tumors 1 cm or smaller between April 2003 and December 2007. Patients were categorized according to HER2 status and pathological tumor size (pT <5 mm vs. 5-10 mm), hormone receptor (HR) status and adjuvant chemotherapy. The primary endpoint was RFS. RESULTS: Of 267 patients included in the analysis, 42 had HER2-positive tumors. The median follow-up was 4.3 years. RFS was worse in patients with HER2-positive tumors than HER2-negative tumors (90.5 vs. 97.7% at 5 years; P = 0.031). In the group with HER2-positive tumors, there were no recurrences in patients with pT<5 mm, but 4 recurrences in those with pT 5-10 mm. RFS was worse in patients with pT 5-10 mm than pT <5 mm (79.0 vs. 100%, P = 0.025). Furthermore 3 recurrences occurred in patients without adjuvant trastuzumab, and 1 recurrence occurred as soon as adjuvant trastuzumab was finished. Our results appear to establish the efficacy of adjuvant trastuzumab therapy. HR status and use of adjuvant chemotherapy were not significantly associated with RFS. CONCLUSIONS: Patients with HER2-positive, node-negative breast tumors 1 cm or smaller (especially 0.5-1.0 cm) have a significant recurrence risk and the decision to employ adjuvant trastuzumab therapy should be discussed with patients based on our results and those of other studies.

[Elderly patient with recurrent rectal cancer successfully responded to modified FOLFOX6 chemotherapy with bevacizumab--a case report].

An 80-year-old female visited our hospital with the chief complaint of lower abdominal pain and diarrhea. She was diagnosed to have rectal cancer. Hartmann operation was performed and curative resection was successfully achieved. Postoperative stage was III according to the classification of the Japanese Society for Cancer of the Colon and Rectum(The 7th Edition). She was treated with oral tegafur(UFT 300mg/body/day)as adjuvant chemotherapy for 6 months. Paraaortic lymph node metastasis and local recurrence were diagnosed by abdominal CT 1 year after the surgery. Her performance status score was 0. She was treated with modified FOLFOX6 chemotherapy combined with bevacizumab. Abdominal CT revealed a partial response after 5 courses. She experienced grade 2 leukocyopenia, grade 3 neutropenia, grade 2 proteinuria and grade 2 hypertension.

Different reactivities of enzyme-linked immunosorbent assays for hepatocyte growth factor.

BACKGROUND: Hepatocyte growth factor (HGF) plays diverse roles in organ development, tissue regeneration, and tumor progression. Measurement of HGF concentrations in blood and tissues using enzyme-linked immunosorbent assay (ELISA) is a simple and easy way to understand the significance of HGF in tissue regeneration, pathophysiology, and diagnosis. METHODS: We evaluated 3 ELISA kits from different sources, referred to herein as kits A, B, and C for convenience. RESULTS: We found that the concentrations of human HGF determined using ELISA vary significantly depending on the source of the ELISA kit. Kits A and B detected both single-chain pro-HGF and 2-chain mature HGF, but kit C detected only 2-chain HGF. A difference in reactivity was also detected during analysis of plasma samples. When rat plasma collected 4 h after subcutaneous administration of human HGF was analyzed, the HGF concentration determined using kit B was remarkably higher than those obtained using kits A and C. Results of a biological assay and Western blot analysis indicated that kit B detects even degraded HGF, by which the HGF concentrations determined using kit B were significantly overestimated. CONCLUSIONS: This information serves as a guide for the selection of ELISA kits for human HGF.

Generation of engineered recombinant hepatocyte growth factor cleaved and activated by Genenase I.

Hepatocyte growth factor (HGF) is biosynthesized as a biologically inactive, single-chain form (pro-HGF). Its activation is associated with cleavage at Arg494-Val495 into a two-chain mature form composed of disulfide-linked alpha- and beta-chains. Because serum is a major source of HGF activator (the predominant serine protease responsible for the processing of pro-HGF), serum-free production of recombinant, two-chain HGF had not been established. In this study, to enable serum-free production of two-chain HGF, we generated engineered human pro-HGFs that can be specifically cleaved and activated by Genenase I. Since Genenase I specifically cleaves the C-terminus of the His-Tyr sequence, which does not exist in human HGF, Arg494 (the C-terminus of the HGF alpha-chain) was replaced by His-Tyr, Ala-Ala-His-Tyr, Pro-Gly-His-Tyr, or Pro-Gly-Ala-Ala-His-Tyr. Genenase I cleaved engineered pro-HGFs specifically at the replaced amino acid sequences, forming a disulfide-linked two-chain form. The cleavage was most efficient in the case of the Pro-Gly-Ala-Ala-His-Tyr sequence, and cleaved HGFs displayed biological activities identical to those of wild-type HGF. Considering a potential medical application of HGF, the present technique is valuable because it enables the production of recombinant, two-chain HGF entirely without serum and extends the choice of host cells and organisms for recombinant production.

The effects of spacer sequences on silencing efficiency of plant RNAi vectors.

RNA interference (RNAi) has been used to suppress gene expression in various eukaryotic organisms. In plants, RNAi can be induced by introduction of an RNAi vector that transcribes a self-complementary hairpin RNA. Most basic RNAi constructs have an inverted repeat interrupted with a spacer sequence. To test silencing capability of RNAi constructs, we developed an in vivo assay that is based on the RNAi-mediated changes of the alpha-linolenic acid content in hairy roots. A tobacco endoplasmic reticulum omega-3 fatty acid desaturase (NtFAD3) is the main enzyme for production of alpha-linolenic acid of root membrane lipids. Tobacco hairy roots transformed with the RNAi vectors against the NtFAD3 gene showed a decrease in alpha-linolenic acid content. The frequency of RNA silencing was more affected by spacer sequence than by spacer length, at least between 100 and 1800 bp. Since significant amounts of hairpin RNA against the NtFAD3 gene remained in the transgenic plants displaying a weak silencing phenotype, low degree of silencing was attributed to low efficiency of hairpin RNA processing mediated by Dicer-like proteins. Our results show the possibility of producing a broad range of the RNAi-induced silencing phenotypes by replacing the spacer sequence of RNAi construct.