Mitotic Spindle Positioning (MISP) Facilitates Colorectal Cancer Progression by Forming a Complex with Opa Interacting Protein 5 (OIP5) and Activating the JAK2-STAT3 Signaling Pathway.

Patients with inflammatory bowel disease (IBD) who experience long-term chronic inflammation of the colon are at an increased risk of developing colorectal cancer (CRC). Mitotic spindle positioning (MISP), an actin-binding protein, plays a role in mitosis and spindle positioning. MISP is found on the apical membrane of the intestinal mucosa and helps stabilize and elongate microvilli, offering protection against colitis. This study explored the role of MISP in colorectal tumorigenesis using a database, human CRC cells, and a mouse model for colitis-induced colorectal tumors triggered by azoxymethane (AOM)/dextran sodium sulfate (DSS) treatment. We found that MISP was highly expressed in colon cancer patient tissues and that reduced MISP expression inhibited cell proliferation. Notably, MISP-deficient mice showed reduced colon tumor formation in the AOM/DSS-induced colitis model. Furthermore, MISP was found to form a complex with Opa interacting protein 5 (OIP5) in the cytoplasm, influencing the expression of OIP5 in a unidirectional manner. We also observed that MISP increased the levels of phosphorylated STAT3 in the JAK2-STAT3 signaling pathway, which is linked to tumorigenesis. These findings indicate that MISP could be a risk factor for CRC, and targeting MISP might provide insights into the mechanisms of colitis-induced colorectal tumorigenesis.

Involvement of Bmal1 and Clock in Bromobenzene Metabolite-Induced Diurnal Renal Toxicity.

Circadian rhythms are endogenous oscillators that regulate 24 h behavioral and physiological processes. Our previous investigation demonstrated that bromobenzene metabolite (4-bromocatechol: 4-BrCA) exhibited chronotoxicity (i.e., the nephrotoxicity induced by 4-BrCA was observed during the dark phase, while not observed at light phase in mice). However, the molecular mechanism is still unknown. The aim of the present study is to investigate the cellular molecule(s) involved in the 4-BrCA-induced nephrotoxicity using mouse renal cortex tubular cell lines (MuRTE61 cells). We found that 4-BrCA showed dose dependent (0.01-1 mM) cell proliferation defect in MuRTE61 cells. By treating with 0.03 mM 4-BrCA, we demonstrated that major clock genes (Bmal1, Clock, Cry1, Cry2, Per1, and Per2) were significantly downregulated. Interestingly, the expression levels of two genes, Bmal1 and Clock, continued to decrease after 3 h of treatment with 4-BrCA, while Cry1, Per1, and Per2 were unchanged until 24 h of treatment. Moreover, BMAL1 and CLOCK levels are higher at light phase. We speculated that BMAL1 and CLOCK might function defensively against 4-BrCA-induced nephrotoxicity since the expression levels of Bmal1 and Clock were rapidly decreased. Finally, overexpression of Bmal1 and Clock restored 4-BrCA-induced cell proliferation defect in MuRTE61 cells. Taken together, our results suggest that Bmal1 and Clock have protective roles against 4-BrCA-induced nephrotoxicity.

Molecular and Pathological Analyses of IARS1-Deficient Mice: An IARS Disorder Model.

Most mitochondrial diseases are hereditary and highly heterogeneous. Cattle born with the V79L mutation in the isoleucyl-tRNA synthetase 1 (IARS1) protein exhibit weak calf syndrome. Recent human genomic studies about pediatric mitochondrial diseases also identified mutations in the IARS1 gene. Although severe prenatal-onset growth retardation and infantile hepatopathy have been reported in such patients, the relationship between IARS mutations and the symptoms is unknown. In this study, we generated hypomorphic IARS1V79L mutant mice to develop an animal model of IARS mutation-related disorders. We found that compared to wild-type mice, IARSV79L mutant mice showed a significant increase in hepatic triglyceride and serum ornithine carbamoyltransferase levels, indicating that IARS1V79L mice suffer from mitochondrial hepatopathy. In addition, siRNA knockdown of the IARS1 gene decreased mitochondrial membrane potential and increased reactive oxygen species in the hepatocarcinoma-derived cell line HepG2. Furthermore, proteomic analysis revealed decreased levels of the mitochondrial function-associated protein NME4 (mitochondrial nucleoside diphosphate kinase). Concisely, our mutant mice model can be used to study IARS mutation-related disorders.

A single amino acid substitution in PRKDC is a determinant of sensitivity to Adriamycin-induced renal injury in mouse.

Adriamycin (ADR)-induced nephropathy is frequently utilized in rodent models of podocytopathy. However, the application of this model in mice is limited to a few strains, such as BALB/c mice. The most commonly used mouse strain, C57BL/6 (B6), is resistant to ADR-induced nephropathy, as are all mouse strains with a B6 genetic background. Reportedly, the R2140C variant of the Prkdc gene is the cause of susceptibility to ADR-induced nephropathy in mice. To verify this hypothesis, we produced Prkdc mutant B6 mice, termed B6-PrkdcR2140C, that possess the R2140C mutation. After administration of ADR, B6-PrkdcR2140C mice exhibited massive proteinuria and glomerular and renal tubular injuries. In addition, there was no significant difference in the severity between B6-PrkdcR2140C and BALB/c. These findings demonstrated that B6-PrkdcR2140C show ADR-induced nephropathy susceptibility at a similar level to BALB/c, and that the PRKDC R2140C variant causes susceptibility to ADR-induced nephropathy. In future studies, ADR-induced nephropathy may become applicable to various kinds of genetically modified mice with a B6 background by mating with B6-PrkdcR2140C.

New inducible mast cell-deficient mouse model (Mcpt5/Cma1DTR).

Mast cell-deficient mice are helpful for understanding the roles of mast cells in vivo. To date, a dozen mouse models for mast cell deficiency have been reported. However, mice with a specific depletion of all populations of mast cells have not been reported. We generated knock-in mice, termed Mcpt5/Cma1DTR mice, expressing human diphtheria toxin A (DT) receptor under the endogenous promoter of Mcpt5 (also known as Cma1), which encodes mouse mast cell protease-5. Flow cytometry and histological analysis showed that intraperitoneal injection of DT induced almost complete depletion of mast cells in heterozygote Mcpt5/Cma1DTR/+ mice. The deletion rates of mast cells in peritoneal cavity, mesentery, abdominal skin, ear skin, and glandular stomach were 99.9%, 100%, 98.7%, 97.7%, and 100%, respectively. Passive cutaneous anaphylaxis reaction also revealed mast cell deficiency in ear skin after DT treatment. Other than mast cells, a small percentage of marginal zone B cells in Mcpt5/Cma1DTR/+ mice were killed by DT treatment. In conclusion, the Mcpt5/Cma1DTR/+ mouse model is valuable for achieving conditional depletion of all populations of mast cells without inducing a marked reduction in other cells.

Genetic loci for resistance to podocyte injury caused by the tensin2 gene deficiency in mice.

BACKGROUND: Tensin2 is a focal adhesion-localized multidomain protein expressed in various tissues, and its dysfunction leads to alterations in podocytes. However, these podocyte-related manifestations are dependent on murine strain. Tensin2 dysfunction results in susceptible strains developing podocyte foot process effacement and massive albuminuria, whereas podocytes in resistant strains remain almost intact. In our previous studies, quantitative trait loci analysis and congenic analysis using resistant C57BL/6J and susceptible ICGN mice identified a modifier locus associated with podocyte injury caused by tensin2 dysfunction on chromosome 2. However, the effect of this modifier locus on chromosome 2 is insufficient to explain the resistance of C57BL/6J mice to tensin2 dysfunction, indicating the existence of other modifier genes. RESULTS: Whereas previous studies focused on the severity of chronic kidney disease, the present study focused on podocyte injury. We performed a genome-wide linkage analysis of backcrosses between two tensin2-deficient mouse strains, B6.ICGN-Tns2 nph and FVB.ICGN-Tns2 nph , and detected a novel major modifier locus on chromosome 10. The combined effect of the C57BL/6J alleles of the two loci on chromosomes 2 and 10 reduced the urinary albumin excretion caused by tensin2 dysfunction to a level comparable to that of C57BL/6J mice. CONCLUSIONS: These data indicate that the resistance to podocyte injury caused by tensin2 dysfunction is mainly produced by the effects of the modifier genes on the two loci. The identification of these modifier genes is expected to help elucidate the mechanism underlying podocyte injury.

Long-term clinical outcomes of endoscopic submucosal dissection for colorectal neoplasms in 423 cases: a retrospective study.

Background and study aim Endoscopic submucosal dissection (ESD) is known as a curative treatment for colorectal superficial neoplasms. There is however a need for more long-term clinical data to establish the full advantages of colorectal ESD regarding very low recurrence rates. The aim of this retrospective study was to determine long-term clinical outcomes of colorectal ESD. Methods A total of 423 lesions treated by ESD for colorectal adenoma/dysplasia or adenocarcinoma between 1998 and 2008 at a single high volume referral center were included. We conducted a retrospective survey on patients with follow-up and obtained complete 1-, 3-, and 5-year outcome data for 358 (85 %), 292 (69 %), and 209 (49 %) lesions, respectively. Curative resection was defined when the pathological specimen had carcinoma-free resection margins, irrespective of piecemeal or en bloc resection, without submucosal deep invasion (≥ 1000 µm), lymphovascular involvement, or a poorly differentiated adenocarcinoma component. Results After a median 4.9 years of follow-up, the 3-year overall cumulative endoscopic recurrence rate and cancerous recurrence rate were 2.9 % (95 % confidence interval [95 %CI] 1.2 - 4.7) and 1.1 % (0 - 2.1), respectively. The 5-year overall cumulative endoscopic recurrence and cancerous recurrence rates were 3.8 % (1.7 - 5.9) and 1.6 % (0.1 - 3.0), respectively. In 361 lesions eligible for endoscopic follow-up, the 3-year endoscopic recurrence and cancerous recurrence rates were 2.4 % (0.8 - 4.1) and 0.4 % (0 - 1.4), respectively. Multivariate analysis revealed that piecemeal resection and submucosal deep tumor invasion were associated with recurrence. Conclusions The current study demonstrated favorable long-term clinical outcomes of colorectal ESD when en bloc curative resection is achieved.

Mouse chromosome 2 harbors genetic determinants of resistance to podocyte injury and renal tubulointerstitial fibrosis.

BACKGROUND: Tensin2 deficiency results in alterations in podocytes and subsequent glomerular and tubulointerstitial injuries. However, this pathology is critically dependent on genetic background. While the Tensin2-deficient podocytes of resistant murine strains, including C57BL/6J mice, remain almost intact, susceptible murine strains with Tensin2 deficency, including ICGN mice, develop chronic kidney disease following alterations in the podocyte foot processes. In a previous study, genome-wide linkage analysis was utilized to identify the quantitative trait loci associated with the disease phenotypes on mouse chromosome 2. This study investigated the disease phenotypes of chromosome 2 consomic and subcongenic strains. RESULTS: ICGN consomic mice introgressed with chromosome 2 from the C57BL/6J mouse were generated and found to exhibit milder renal failure than that in ICGN mice. We developed 6 subcongenic strains that carry C57BL/6J-derived chromosomal segments from the consomic strain. One showed significantly milder albuminuria, another showed significantly milder tubulointerstitial injury, and the both showed significantly milder glomerular injury. CONCLUSIONS: These data indicate that mouse chromosome 2 harbors two major genes associated with the severities of nephropathy induced by Tensin2 deficiency. The proximal region on chromosome 2 contributes to the resistance to tubulointerstitial fibrosis. In contrast, the distal region on chromosome 2 contributes to the resistance to podocyte injury. This study would be helpful to discover the biological mechanism underlying the renal injury, and may lead to the identification of therapeutic targets.

Nerve Growth Factor Expression Is Not Associated with Perineural Invasion in Extrahepatic Cholangiocarcinoma.

BACKGROUND: Although the presence of perineural invasion has been recognized as a poor prognostic factor in extrahepatic cholangiocarcinoma, the molecular mechanisms of perineural invasion in extrahepatic cholangiocarcinoma remain unclear. Nerve growth factor has been reported to be a candidate predictive biomarker of perineural invasion in some cancers. AIM: To investigate the impact of intratumoral nerve growth factor expression in resected extrahepatic cholangiocarcinoma on survival. METHODS: Intratumoral nerve growth factor expression was investigated immunohistochemically in 112 patients with resected extrahepatic cholangiocarcinoma. Associations between nerve growth factor expression and clinicopathological factors were statistically evaluated, and risk factors for poor survival were analyzed using univariate and multivariate analyses. RESULTS: High and low nerve growth factor expression was observed in 62 (55%) and 50 (45%) patients, respectively. For all 112 patients, no significant correlation was found between nerve growth factor expression and presence of perineural invasion (P = 0.942). Moreover, nerve growth factor expression was not associated with recurrence-free survival (P = 0.861) and overall survival (P = 0.973). In multivariate analysis, lymph node metastasis (P = 0.004) was identified as an independent risk factor for early recurrence and the presence of perineural invasion (P = 0.002) and lymph node metastasis (P < 0.001) was identified as independent risk factors for poor survival. CONCLUSIONS: Intratumoral nerve growth factor expression is not associated with perineural invasion or recurrence-free and overall survival in patients with resected extrahepatic cholangiocarcinoma.

Does the routine handling affect the phenotype of disease model mice?

The three different mouse handling methods, picking up by tails, tunnels, and open hands were performed using the ICGN glomerulonephritis mouse and the severity of symptoms was evaluated. The handling groups exhibited a tendency of more severe symptoms than the non-handling control group. Female mice handled by their tails showed significantly more severe symptoms than the control group. In addition, we subjected the normal laboratory mice, C57BL/6 and BALB/c mice to tail and tunnel handling to assess the stress conditions. The plasma corticosterone level in the tail-handled mice was higher than that in control mice. These results indicate that handling causes stress and may affect the phenotype of disease model mice.

Does preoperative biliary drainage compromise the long-term survival of patients with pancreatic head carcinoma?

BACKGROUND AND OBJECTIVES: The aim of this study was to determine the impact of preoperative biliary drainage (PBD) on long-term survival in patients with pancreatic head carcinoma after surgical resection. METHODS: Medical records of 160 patients with pancreatic head carcinoma who underwent surgical resection were reviewed retrospectively. Clinicopathological parameters including long-term survival were compared between patients who did and did not undergo PBD. RESULTS: Overall survival of patients who underwent PBD (n = 93) was significantly worse than that of patients who did not (n = 67) by univariate analysis (P = 0.030). However, multivariate analysis revealed that PBD was not an independent prognostic factor for overall survival (P = 0.227). Patients who underwent percutaneous transhepatic biliary drainage (PTBD) had significantly worse survival than patients who underwent endoscopic retrograde biliary drainage (ERBD, P = 0.038) and patients who did not undergo PBD (P = 0.001). The rate of peritoneal recurrence in patients who underwent PTBD was significantly higher than that of patients who underwent ERBD (P = 0.033) or patients who did not undergo PBD (P = 0.034). CONCLUSIONS: PBD may not affect the long-term survival of patients with pancreatic head carcinoma if ERBD is used.

A pilot study of fluorescent imaging of colorectal tumors using a γ-glutamyl-transpeptidase-activatable fluorescent probe.

UNLABELLED: Backgrounds/Aim: Colorectal laterally spreading tumors (LSTs) are sometimes difficult to visualize even with image-enhanced endoscopy. γ-Glutamyl-transpeptidase (GGT) is a cell surface-associated enzyme that is overexpressed in various types of human cancers. Furthermore, GGT expression is higher in colorectal cancer cells than in normal colorectal mucosa. γ-Glutamyl hydroxymethyl rhodamine green (gGlu-HMRG), an activatable fluorescent probe, is nonfluorescent under a neutral pH and normal cellular environment; however, it turns highly fluorescent upon reaction with GGT. We evaluated ex vivo fluorescent imaging of colorectal LSTs using this GGT-activatable fluorescent probe. METHODS: Between March 2013 and March 2014, 30 endoscopically resected colorectal LSTs were prospectively included in this study. Each was analyzed by first taking a baseline image before spraying, then spraying with gGlu-HMRG onto the freshly resected specimen, and finally taking fluorescent images 15 min after spraying with a dedicated imaging machine. RESULTS: Of the LSTs, 67% rapidly showed positive fluorescent activity. These activities were shown in adenoma (54%) and carcinoma in adenoma (76%), and in LST-granular type (80%) and LST-nongranular type (40%). CONCLUSION: Topically spraying gGlu-HMRG enabled rapid and selective fluorescent imaging of colorectal tumors owing to the upregulated GGT activity in cancer cells.

Is pancreatic fistula associated with worse overall survival in patients with pancreatic carcinoma?

BACKGROUND: Pancreatic fistula (PF) is one of the leading complications after pancreatic resection for pancreatic carcinoma. The aim of this study was to determine whether PF was associated with deterioration of long-term outcomes in patients with pancreatic carcinoma after surgical resection. METHODS: Medical records of 210 patients with pancreatic carcinoma who underwent tumor resection were reviewed retrospectively. PF was defined as grade B or C PF according to the criteria of the International Study Group on Pancreatic Fistula. Clinicopathological factors including overall survival were compared between patients with and without PF by univariate and multivariate analyses. RESULTS: Thirty-one patients (15 %) developed postoperative PF, and 179 (85 %) did not. The 31 cases of PF consisted of 27 grade B PF and 4 grade C PF. There were no differences in the use of adjuvant chemotherapy, tumor differentiation, lymph node status, surgical margin status, or UICC stage between groups. Overall 5-year survival rates for patients with and without PF were 25 and 27 %, respectively. There was no significant difference in overall survival between the two groups (P = 0.743). Multivariate analysis demonstrated that the use of postoperative adjuvant chemotherapy (P < 0.001), tumor differentiation (P = 0.005), and lymph node metastasis (p < 0.001) were factors independently associated with overall survival. CONCLUSIONS: These results suggested that PF was not associated with deterioration of long-term outcomes in patients with pancreatic carcinoma. However, further analyses on larger number of patients are needed to determine a negative effect of grade C PF on long-term survival.

Elevated perioperative serum CA 19-9 levels are independent predictors of poor survival in patients with resectable cholangiocarcinoma.

BACKGROUND AND OBJECTIVES: Identification of prognostic markers is important to establish a perioperative therapeutic strategy for resectable cholangiocarcinoma (CC). The aim of this study was to investigate whether perioperative serum carbohydrate antigen 19-9 (CA19-9) levels can predict survival of patients who underwent surgical resection for CC. METHODS: The study included 106 patients who underwent surgical resection for CC. Serum CA19-9 levels were measured preoperatively after biliary drainage and postoperatively about 4 weeks after surgery. The association of clinicopathological factors (including perioperative serum CA19-9 levels) with overall survival (OS) was analyzed with univariate and multivariate analyses. RESULTS: Differences in OS were significant between groups divided on the basis of two preoperative CA19-9 cutoff values (in U/ml) of 37 and 200 and three postoperative CA19-9 cutoff values (in U/ml) of 37, 100, and 200. In multivariate analysis, absence of postoperative adjuvant chemotherapy (P = 0.002), lymph node metastasis (P = 0.0002), preoperative CA19-9 (≥ 200 IU/ml) (P = 0.03), and postoperative CA19-9 (≥ 37 IU/ml) (P < 0.0001) were identified as independent predictors of poor OS. CONCLUSION: Both pre- and postoperative serum CA19-9 levels predict the survival of patients with resectable CC, and may contribute to the establishment of a new therapeutic strategy.

Nonalcoholic fatty liver disease after pancreatoduodenectomy is closely associated with postoperative pancreatic exocrine insufficiency.

BACKGROUND: In recent years, nonalcoholic fatty liver disease (NAFLD) after pancreatoduodenectomy (PD) has become increasingly problematic. Our aims were to clarify the relationship between NAFLD and postoperative pancreatic exocrine function and to identify the risk factors for NAFLD after PD. METHODS: Patients who underwent PD (n = 104) were assessed with abdominal unenhanced computed tomography (CT) to determine the fatty liver changes and were given a (13) C-labeled mixed triglyceride breath test to measure pancreatic exocrine function. The percent (13) CO2 cumulative dose at 7 hr (% dose (13) C cum 7 hr) <5% was considered diagnostic for pancreatic exocrine insufficiency (PEI). Relationships between the occurrence of NAFLD and clinical factors including postoperative pancreatic exocrine function were analyzed. RESULTS: Twenty-six of 104 patients (25%) developed postoperative NAFLD. The postoperative CT attenuation of the liver (R = 0.326, P < 0.001) and the liver-to-spleen attenuation ratio (R = 0.315, P = 0.001) significantly correlated with the postoperative values of % dose (13) C cum 7 hr. Multivariate analysis determined that postoperative PEI was the only independent risk factor for NAFLD (P = 0.025). CONCLUSIONS: NAFLD frequently occurs postoperatively after PD. NAFLD after PD may be closely associated with postoperative PEI.

Indicators for proper management of surgical drains following pancreaticoduodenectomy.

BACKGROUND: The indicators for proper drain management following pancreaticoduodenectomy (PD) remain unclear. Our aim was to identify appropriate timing and proper indicators for safe drain management after PD. METHODS: Prospectively collected data from 200 patients who underwent PD were evaluated. Postoperative clinical factors for clinically relevant pancreatic fistulas (CR-POPFs) and management of surgically placed drains were analyzed retrospectively. RESULTS: CR-POPFs occurred in 8% of patients. By logistic regression analysis, one factor (non-serous fluid in the drain) on postoperative day (POD) 1 and two factors (non-serous fluid in the drain and serum CRP levels) on POD 3 and 4 were significantly associated with CR-POPFs. Receiver operating characteristic analysis demonstrated that combined predictive factors on POD 4 were the most accurate. Of 163 patients with serous fluid in the drain and CRP <15.6 mg/dl on POD 4, 1% had CR-POPFs, but no patient required POPF-related re-drainage. In contrast, among 37 patients with non-serous fluid in the drain or CRP levels ≥15.6 mg/dl, 35% had CR-POPFs, and 8% required POPF-related re-drainage. CONCLUSIONS: A combination of CRP levels and the color of surgical drain fluid, not POD1 or 3, but on POD 4, may be the most accurate indicators for safe drain management following PD.

Automated scoring of glomerular injury in TNS2-deficient nephropathy.

Several artificial intelligence (AI) systems have been developed for glomerular pathology analysis in clinical settings. However, the application of AI systems in nonclinical fields remains limited. In this study, we trained a convolutional neural network model, which is an AI algorithm, to classify the severity of Tensin 2 (TNS2)-deficient nephropathy into seven categories. A dataset consisting of 803 glomerular images was generated from kidney sections of TNS2-deficient and wild-type mice. Manual evaluations of the images were conducted to assess their glomerular injury scores. The trained AI achieved approximately 70% accuracy in predicting the glomerular injury score for TNS2-deficient nephropathy. However, the AI achieved approximately 100% accuracy when considering predictions within one score of the true label as correct. The AI's predicted mean score closely matched the true mean score. In conclusion, while the AI model may not replace human judgment entirely, it can serve as a reliable second assessor in scoring glomerular injury, offering potential benefits in enhancing the accuracy and objectivity of such assessments.

Close relations between podocyte injuries and membranous proliferative glomerulonephritis in autoimmune murine models.

BACKGROUND: Membranous proliferative glomerulonephritis (MPGN) is a major primary cause of chronic kidney disease (CKD). Podocyte injury is crucial in the pathogenesis of glomerular disease with proteinuria, leading to CKD. To assess podocyte injuries in MPGN, the pathological features of spontaneous murine models were analyzed. METHODS: The autoimmune-prone mice strains BXSB/MpJ-Yaa and B6.MRL-(D1Mit202-D1Mit403) were used as the MPGN models, and BXSB/MpJ-Yaa(+) and C57BL/6 were used as the respective controls. In addition to clinical parameters and glomerular histopathology, the protein and mRNA levels of podocyte functional markers were evaluated as indices for podocyte injuries. The relation between MPGN pathology and podocyte injuries was analyzed by statistical correlation. RESULTS: Both models developed MPGN with albuminuria and elevated serum anti-double-strand DNA (dsDNA) antibody levels. BXSB/MpJ-Yaa and B6.MRL showed severe proliferative lesions with T and B cell infiltrations and membranous lesions with T cell infiltrations, respectively. Foot process effacement and microvillus-like structure formation were observed ultrastructurally in the podocytes of both MPGN models. Furthermore, both MPGN models showed a decrease in immune-positive areas of nephrin, podocin and synaptopodin in the glomerulus, and in the mRNA expression of Nphs1, Nphs2, Synpo, Actn4, Cd2ap, and Podxl in the isolated glomerulus. Significant negative correlations were detected between serum anti-dsDNA antibody levels and glomerular Nphs1 expression, and between urinary albumin-to-creatinine ratio and glomerular expression of Nphs1, Synpo, Actn4, Cd2ap, or Podxl. CONCLUSION: MPGN models clearly developed podocyte injuries characterized by the decreased expression of podocyte functional markers with altered morphology. These data emphasized the importance of regulation of podocyte injuries in MPGN.

Genetic background strongly influences the transition to chronic kidney disease of adriamycin nephropathy in mice.

Animal models of podocytopathy and chronic kidney diseases (CKD) help elucidate these pathologies. Adriamycin (ADR)-induced nephropathy is a common rodent model of podocytopathy. BALB/c mice are sensitive to ADR, whereas C57BL/6 (B6) mice, the most commonly used strain, are resistant to ADR. Therefore, mouse strains with the B6 genetic background cannot be used as an ADR nephropathy model. We previously generated DNA-dependent protein kinase catalytic subunit (Prkdc) mutant B6 mice (B6-PrkdcR2140C) carrying the R2140C mutation that causes ADR nephropathy. However, whether ADR nephropathy in the novel strain progresses to CKD after ADR administration has not been evaluated. Therefore, we examined whether the B6-PrkdcR2140C mice develop CKD after ADR administration. We also evaluated whether differences existed in the genetic background in ADR nephropathy by comparing the B6-PrkdcR2140C mice with BALB/c mice. Our findings demonstrated that B6-PrkdcR2140C progresses to CKD and is resistant to nephropathy compared with the BALB/c mice. The B6-PrkdcR2140C and BALB/c mice differed in the expression of genes related to inflammatory mediators, and further analysis is required to identify factors that contribute to resistance to nephropathy.

Differences in susceptibility to ADR nephropathy among C57BL/6 substrains.

Adriamycin (ADR) nephropathy is the most widely used nephropathy model to study the pathophysiological mechanisms of chronic kidney disease (CKD) in mice. However, its application is limited to a few mouse strains such as the BALB/c strain; the standard strain, C57BL/6J (B6J), does not develop ADR nephropathy. Nevertheless, Arif et al. reported that C57BL/6N (B6N), another standard strain, is ADR-susceptible. Since then, no follow-up reports or other studies have been published on ADR nephropathy in B6N mice. Therefore, the goal of this study was to determine whether B6N mice are indeed susceptible to ADR nephropathy and whether there are differences in ADR susceptibility among the substrains of C57BL/6NCrl (NCrl) and C57BL/6NJcl (NJcl). NCrl mice showed marked albuminuria and mesangial cell proliferation, which are associated with mild ADR nephropathy, confirming that NCrl mice were susceptible to ADR nephropathy. On the other hand, NJcl mice did not exhibit these symptoms. ADR nephropathy models are usually generated by administering ADR through the tail vein, but Arif et al. administered ADR through the orbital vein. Therefore, we investigated the effect of the route of administration on ADR nephropathy. The degree of ADR nephropathy was found to vary based on the route of administration: more severe nephropathy was observed upon administration through the tail vein than through the orbital vein. Therefore, we conclude that NCrl mice are susceptible to ADR nephropathy, and the severity of ADR-induced nephropathy through orbital vein administration is relatively lower than that through the tail vein.