Nonalbuminuric proteinuria as a biomarker for tubular damage in early development of nephropathy with type 2 diabetic patients

AIM

The aim of this study was to evaluate the association between urinary nonalbumin protein (NAP) and urinary tubular markers in early diabetic nephropathy.

METHODS

Urinary NAP was measured in 118 patients with type 2 diabetes with estimated glomerular filtration rates (eGFR) ≥60 mL/min/1.73 m². Urine levels of tubular markers [kidney injury molecule (KIM)-1, neutrophil gelatinase-assoicated lipocalin (NGAL) and liver-type fatty acid-binding protein (L-FABP)] were measured by using an Enzyme-linked immunosorbent assay (ELISA). Patients were divided into three groups according to urinary NAP values.

RESULTS

The urine levels of KIM-1, NGAL and L-FABP were significantly higher in the third tertile group than in the first tertile group (all p < 0.001). There was a significant positive correlation between NAP and each tubular marker (KIM-1, NGAL and L-FABP) in univariate analysis (all p < 0.001). Urinary NAP was positively correlated with all urinary tubular markers after adjustment for age, duration of diabetes, systolic blood pressure, eGFR, low-density lipoprotein cholesterol, HbA1c and albumin-to-creatinine ratio (KIM-1 r = 0.170, p < 0.001; NGAL r = 0.142, p < 0.015 and L-FABP r = 0.262, p < 0.001). In normoalbuminuric patients (n = 58), urinary NAP was also significantly correlated with NGAL and L-FABP in multivariate regression analyses (r = 0.302, p = 0.030 and r = 0.430, p = 0.001).

CONCLUSIONS

These findings suggest that urinary NAP reflects tubular damage in the early-stage type 2 diabetic nephropathy (eGFR ≥ 60 mL/min/1.73 m²). We suggest that urinary NAP could be used as a biomarker for tubular damage in clinical practice.

Complete mitochondrial genome of Sebastes hubbsi (Scorpaenidae, Scorpaeniformes) from the East Sea, Korea

Hybrids of Sebastes hubbsi, considered a valid species, have been found in the ocean. To examine the basic characteristics of mitochondrial DNA, we analysed the complete mitogenome of S. hubbsis using next-generation sequencing. The complete mitogenome was 16,453 bp in length and comprised 13 protein-coding genes (PCGs), 2 rRNAs, 22 tRNAs and 1 control region. The complete mitochondrial DNA had 27.9% A, 26.7% T, 17.2% G and 28.3% C, showing a slight AT bias (54.5%). The start codon of all PCGs was ATG, except COX1 (GTG). The stop codons in the PCGs were mainly TAA, except ND1 and ND3 (TAG), ND4 (AGA) and Cytb (incomplete termination codon, T). The tRNAs had a typical cloverleaf structure, except tRNA(Ser (AGY)) which lacked the DHU arm. The complete mitogenome of S. hubbsi can be used for hybridization or on-going speciation studies within allied species in the Scorpaenidae.

Abstract 523: Detection of PIWI-piRNAS in the mitochondria of human normal and cancer cells

Piwi-interacting RNAs (piRNAs) are a class of small non-coding RNAs that regulate differentiation in primordial germ cells, found mainly in the nucleus and cytoplasm. However, despite the essentiality of mitochondria to intrinsic apoptosis and energy metabolism, the presence of piRNAs (and their associated Piwi proteins) in this organelle remains largely unknown. In this study, a public database comparison of mitochondrial RNA-seq data from human normal (HEK293) and cancer (HeLa and 143B) cells revealed the presence of 29 mature piRNA sequences, with 12 of those piRNA sequences perfectly matching 7 tRNAs (Phe, Val, Leu, His, Ser, Glu, and Thr), suggesting piRNAs and tRNAs derive from a common precursor mitochondrial polycistronic transcript. Consistent with their known interaction with piRNAs, further examination revealed the presence of PIWI proteins in mitochondria. Moreover, the majority of the 29 piRNA sequences overlapped multiple longer sequences (expressed sequence tags, ESTs) that uniquely mapped to the mitochondrial genome. To our knowledge, this is the first report of Piwi and piRNAs in the mitochondria of mammalian normal and cancer cells.

Citation Format: ChangHyuk Kwon, Hyosun Tak, Mina Rho, Hae Ryung Chang, Yon Hui Km, Kyung Tae Kim, Eun Kyung Lee, Curt Balch, Seungyoon Nam. Detection of PIWI-piRNAS in the mitochondria of human normal and cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 523. doi:10.1158/1538-7445.AM2014-523

Abstract 2136: Long-term metformin use reduces gastric cancer risk in type 2 diabetics without insulin treatment: a nationwide cohort study

Background: Metformin use has been associated with a decreased incidence and mortality of various cancers.

Aim: The aim of this study was to evaluate the association between metformin use and gastric cancer.

Methods: We randomy selected 100,000 type 2 diabetic patients from the 2004 Korean National Health Insurance claim database, and assessed gastric cancer incidence among 39,989 patients (aged 30-97 years) who were regularly treated with anti-diabetic drugs and followed-up from 2004 to 2010. In total, 26,690 patients had used metformin out of 32,978 diabetics who had not regularly used insulin (insulin non-users), and 5,855 patients had used metformin out of 7,011 regular insulin users.

Results: Patients who used metformin showed a lower incidence of gastric cancer than those who did not use metformin, in insulin non-users (P=0.047, log-rank test). However, in patients on regular insulin, there was no difference of gastric cancer incidence according to metformin use. In insulin non-users, the adjusted hazard ratio (AHR) for metformin use was 0.73 (95% confidential interval [CI], 0.53-1.01) with borderline statistical significance (P=0.059). Duration of metformin use was associated with the reduction of gastric cancer risk (AHR, 0.88; 95% CI 0.81-0.96, P=0.003), especially in patients that used metformin for more than 3 years (AHR, 0.57; 95% CI, 0.37-0.87; P=0.009).

Conclusion: Metformin use &gt;3 years in type 2 diabetics who do not use insulin is associated with significantly reduced gastric cancer risk.

Citation Format: Soo-Jeong Cho, Young-Il Kim, So Young Kim, Jong-Hyock Park, Il Ju Choi, You Jin Lee, Eun Kyung Lee, Myeong-Cherl Kook, Chan Gyoo Kim, Keun Won Ryu, Young-Woo Kim. Long-term metformin use reduces gastric cancer risk in type 2 diabetics without insulin treatment: a nationwide cohort study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2136. doi:10.1158/1538-7445.AM2014-2136

Abstract 4103: Biomarkers of thyroid function and autoimmunity associated with thyroid cancer risk: A nested case-control study

Background & Objective: The incidence of thyroid cancer has been increased in several countries. However, the markers to predict for high-risk group have not been fully established. We aim to investigate the potential association between the biomarkers of thyroid function/autoimmunity and the risk of thyroid cancer in Korean population, where the incidence rate of thyroid cancer is one of the highest in the world.

Design: This study was a nested case-control study within the Cancer Screenee Cohort study, which consisted of 257 incident thyroid cancer patients who were ascertained during mean of 2.2 years of follow-up and 257 controls. Total triidothyronine (TT3), free thyroxine (FT4), thyroid-stimulating hormone (TSH), and thyroglobulin (Tg), and two markers of thyroid autoimmunity (anti-thyroperoxidase [TPOAb] and anti-thyroglobulin [TgAb] antibodies) were measured. Logistic regression models were used to examine the association between these biomarkers and thyroid cancer risk. Stratified analyses were conducted by sex, BMI, and smoking status.

Results: When the markers were categories by tertile distribution of the levels of controls group, highest tertile of FT4 (OR [95% CI] = 1.73[1.11, 2.69]) and middle tertile of TSH (OR [95% CI] = 1.77[1.14, 2.74]) were associated with thyroid cancer risk in multivariate analyses. In addition, normal (30-60 U/mL) (OR [95% CI] = 8.47 [5.39, 13.33]) or elevated levels (60 &gt; U/mL) (OR [95% CI] = 4.48 [2.59, 7.76]) of TPOAb showed an elevated risk for thyroid cancer. Stratified analyses implied that some of these associations could be differed by sex, BMI, or smoking status.

Conclusions: This study represented that the levels of biomarkers of thyroid function/autoimmunity, particularly the presence of TPOAb, may be used as diagnostic adjuncts for predicting thyroid cancer risk.

Citation Format: Jeongseon Kim, Young Ae Cho, Aesun Shin, Jeonghee Lee, Sun-Young Kong, Eun Kyung Lee, You Jin Lee. Biomarkers of thyroid function and autoimmunity associated with thyroid cancer risk: A nested case-control study. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4103. doi:10.1158/1538-7445.AM2014-4103

Fermentation with Aquilariae Lignum enhances the anti-diabetic activity of green tea in type II diabetic db/db mouse

The major components of tea may be significantly influenced according to the type of fermentation, and consequently the effects of different teas will differ. We examined whether green tea fermented with Aquilariae Lignum (fGT) shows a stronger anti-diabetic effect than unfermented green tea (GT) on mice with type 2 diabetes. To evaluate the anti-obesity effect of fGT, we assessed body weight, fecal excretion, serum leptin levels, exocrine pancreatic zymogen granule contents, and periovarian fat weight and adiponectin contents. Blood glucose levels, pancreatic weight, and numbers of pancreatic islet insulin- and glucagon-producing cells were determined to evaluate anti-hypoglycemic effects, while total cholesterol, triglyceride, and low- and high-density lipoprotein levels were determined to evaluate anti-hyperlipidemic effects. The antioxidant effect of fGT was detected by measuring malondialdehyde and glutathione contents and the activities of catalase and superoxide dismutase. fGT showed anti-obesity, anti-hypoglycemic, anti-hyperlipidemia, and antioxidant effects. Additionally, fGT exerted stronger anti-diabetic effects compared with GT. Collectively, these results suggested that fGT fermented with the appropriate amounts of Aquilariae Lignum (49:1) has a stronger effect compared with GT. Thus, fGT is a promising and potent new therapeutic agent for type 2 diabetes.

Therapeutic potential of Dickkopf-1 in wild-type BRAF papillary thyroid cancer via regulation of β-catenin/E-cadherin signaling

BACKGROUND

Aberrant activation of the Wnt/β-catenin pathway is a common pathogenesis of various human cancers. We investigated the role of the Wnt inhibitor, Dkk-1, in papillary thyroid cancer (PTC).

METHODS

Immunohistochemical β-catenin staining was performed in tissue microarray containing 148 PTCs and five normal thyroid tissues. In vivo effects of Dkk-1 were explored using ectopic tumors with BHP10-3SC cells.

RESULTS

In 27 PTC patients, 60% of patients showed β-catenin up-regulation and Dkk-1 down-regulation in tumor vs normal tissues. Tissue microarray analysis showed that 14 of 148 PTC samples exhibited cytoplasmic-dominant β-catenin expression compared to membranous-dominant expression in normal tissues. Aberrant β-catenin expression was significantly correlated with higher rates of the loss of membranous E-cadherin expression and poor disease-free survival than that in the normal membranous expression group over a median follow-up period of 14 years. Implantation of Dkk-1-overexpressing BHP10-3SC cells revealed delayed tumor growth, resulting from the rescue of membranous β-catenin and E-cadherin expressions. Furthermore, tissue microarray analysis demonstrated that BRAF(WT) patients had higher rates of aberrant expressions of β-catenin and E-cadherin than BRAF(V600E) patients. Indeed, the inhibitory effects of Dkk-1 on cell survival were more sensitive in BRAF(WT) (BHP10-3SC and TPC-1) than in BRAF(V600E) (SNU-790 and BCPAP) cells. Overexpression of BRAF(V600E) in normal thyroid epithelial (H tori) cells also reduced the effects of Dkk-1 on cell survival.

CONCLUSION

A subset of PTC patients showed aberrant expression of β-catenin/E-cadherin signaling and poor disease-free survival. Dkk-1 might have a therapeutic role, particularly in BRAF(WT) patients.

Enhancement of tumor-specific T cell-mediated immunity in dendritic cell-based vaccines by Mycobacterium tuberculosis heat shock protein X

Despite the potential for stimulation of robust antitumor immunity by dendritic cells (DCs), clinical applications of DC-based immunotherapy are limited by the low potency in generating tumor Ag-specific T cell responses. Therefore, optimal conditions for generating potent immunostimulatory DCs that overcome tolerance and suppression are key factors in DC-based tumor immunotherapy. In this study, we demonstrate that use of the Mycobacterium tuberculosis heat shock protein X (HspX) as an immunoadjuvant in DC-based tumor immunotherapy has significant potential in therapeutics. In particular, the treatment aids the induction of tumor-reactive T cell responses, especially tumor-specific CTLs. The HspX protein induces DC maturation and proinflammatory cytokine production (TNF-α, IL-1β, IL-6, and IFN-β) through TLR4 binding partially mediated by both the MyD88 and the TRIF signaling pathways. We employed two models of tumor progression and metastasis to evaluate HspX-stimulated DCs in vivo. The administration of HspX-stimulated DCs increased the activation of naive T cells, effectively polarizing the CD4(+) and CD8(+) T cells to secrete IFN-γ, as well as enhanced the cytotoxicity of splenocytes against HPV-16 E7 (E7)-expressing TC-1 murine tumor cells in therapeutic experimental animals. Moreover, the metastatic capacity of B16-BL6 melanoma cancer cells toward the lungs was remarkably attenuated in mice that received HspX-stimulated DCs. In conclusion, the high therapeutic response rates with tumor-targeted Th1-type T cell immunity as a result of HspX-stimulated DCs in two models suggest that HspX harnesses the exquisite immunological power and specificity of DCs for the treatment of tumors.

A long non-coding RNA snaR contributes to 5-fluorouracil resistance in human colon cancer cells

Several types of genetic and epigenetic regulation have been implicated in the development of drug resistance, one significant challenge for cancer therapy. Although changes in the expression of non-coding RNA are also responsible for drug resistance, the specific identities and roles of them remain to be elucidated. Long non-coding RNAs (lncRNAs) are a type of ncRNA (> 200 nt) that influence the regulation of gene expression in various ways. In this study, we aimed to identify differentially expressed lncRNAs in 5-fluorouracil-resistant colon cancer cells. Using two pairs of 5-FU-resistant cells derived from the human colon cancer cell lines SNU-C4 and SNU-C5, we analyzed the expression of 90 lncRNAs by qPCR-based profiling and found that 19 and 23 lncRNAs were differentially expressed in SNU-C4R and SNU-C5R cells, respectively. We confirmed that snaR and BACE1AS were downregulated in resistant cells. To further investigate the effects of snaR on cell growth, cell viability and cell cycle were analyzed after transfection of siRNAs targeting snaR. Down-regulation of snaR decreased cell death after 5-FU treatment, which indicates that snaR loss decreases in vitro sensitivity to 5-FU. Our results provide an important insight into the involvement of lncRNAs in 5-FU resistance in colon cancer cells.

Recurrent hypoglycemia triggered by sorafenib therapy in a patient with hemangiopericytoma

Targeted therapy has been proven to be one of the most effective cancer treatments. However, some endocrine disorders can occur during treatment with targeted agents. We report the case of a patient who exhibited a wax and wane pattern of hypoglycemia that was attributed to sorafenib therapy. A 32-year-old woman with metastatic hemangiopericytoma visited the emergency department in a stuporous state. Nonhyperinsulinemic hypoglycemia was diagnosed, was exacerbated shortly after sorafenib therapy, and was improved by the cessation of sorafenib with additional glucocorticoid therapy. Patients with metastatic hemangiopericytoma should be carefully monitored with particular attention to hypoglycemia when sorafenib therapy is initiated.

Kikuchi-Fujimoto disease mimicking malignant lymphoma with 2-[(18)F]fluoro-2-deoxy-D-glucose PET/CT in children

PURPOSE

Kikuchi-Fujimoto disease (KFD) is a benign disease, which is characterized by a cervical lymphadenopathy with fever, and it often mimics malignant lymphoma (ML). 2-[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) is a powerful imaging modality for the diagnosis, staging and monitoring of ML, with the limitations including the nonspecific FDG uptake in infectious or inflammatory processes. This study compared clinical manifestations and PET/CT findings between KFD and ML patients.

METHODS

We retrospectively reviewed the medical records of 23 patients with KFD and 33 patients with ML, diagnosed histopathologically, between January 2000 and May 2013 at the Department of Pediatrics, Yeungnam University Medical Center. Among them, we analyzed the clinical manifestations, laboratory findings and characteristics, and the amount of (18)F-FDG uptake between 8 KFD and 9 ML patients who had (18)F-FDG PET/CT.

RESULTS

The (18)F-FDG PET/CT maximum standardized uptake values (SUVmax) ranged from 8.3 to 22.5 (mean, 12.0) in KFDs, and from 5.8 to 34.3 (mean, 15.9) in MLs. There were no significant differences in SUVmax between KFDs and MLs. (18)F-FDG PET/CT with ML patients showed hot uptakes in the extranodal organs, such as bone marrow, small bowel, thymus, kidney, orbit and pleura. However, none of the KFD cases showed extranodal uptake (P<0.001). (18)F-FDG PET/CT findings of KFD with nodal involvement only were indistinguishable from those of ML.

CONCLUSION

Patients who had extranodal involvement on PET/CT were more likely to have malignancy than KFD.

Long-term metformin use reduces gastric cancer risk in type 2 diabetics without insulin treatment: a nationwide cohort study

BACKGROUND

Metformin use has been associated with a decreased incidence and mortality of various cancers.

AIM

To evaluate the association between metformin use and gastric cancer.

METHODS

We randomly selected 100 000 type 2 diabetic patients from the 2004 Korean National Health Insurance claim database, and assessed gastric cancer incidence among 39 989 patients (aged 30-97 years) who were regularly treated with anti-diabetic drugs and followed-up from 2004 to 2010. In total, 26 690 patients had used metformin out of 32 978 diabetics who had not regularly used insulin (insulin non-users), and 5855 patients had used metformin out of 7011 regular insulin users.

RESULTS

Patients who used metformin showed a lower incidence of gastric cancer than those who did not use metformin, in insulin non-users (P = 0.047, log-rank test). However, in patients on regular insulin, there was no difference of gastric cancer incidence according to metformin use. In insulin non-users, the adjusted hazard ratio (AHR) for metformin use was 0.73 (95% confidential interval [CI], 0.53-1.01) with borderline statistical significance (P = 0.059). Duration of metformin use was associated with the reduction in gastric cancer risk (AHR, 0.88; 95% CI 0.81-0.96, P = 0.003), especially in patients who used metformin for more than 3 years (AHR, 0.57; 95% CI, 0.37-0.87; P = 0.009).

CONCLUSION

Metformin use >3 years in type 2 diabetics who do not use insulin is associated with a significantly reduced gastric cancer risk.

6-Amino-2,4,5-trimethylpyridin-3-ols: a new general synthetic route and antiangiogenic activity

A new synthetic strategy for preparation of a wide range of 6-amino-2,4,5-trimethylpyridin-3-ols from pyridoxine·HCl via a six-step sequence has been developed. This approach features an introduction of various amino groups to C(6)-position of 3-benzyloxy-6-bromo-2,4,5-trimethylpyridine (13), a key intermediate, by a Buchwald-Hartwig amination reaction using palladium(0) transition metal, which certainly renders an expanded scope of amino substituents. Some analogs prepared using the methods described here showed high level of antiangiogenic and antitumor activities in chick chorioallantoic membrane (CAM) assay, demonstrating the potential of these new aminopyridinols as antiangiogenic agents.

Risk factors for recurrence after therapeutic lateral neck dissection for primary papillary thyroid cancer

BACKGROUND

Lateral lymph node metastasis is an important prognostic factor and is predictive of tumor recurrence and cause-specific survival in patients with papillary thyroid cancer (PTC). However, the factors predicting recurrence and clinical outcomes after therapeutic lateral neck dissection are not well established. The aims of this study were to evaluate the incidence, pattern, and factors predictive of PTC recurrence after therapeutic lateral neck dissection.

MATERIALS AND METHODS

The records of 126 consecutive patients who underwent total thyroidectomy with therapeutic lateral neck dissection for primary PTC at the National Cancer Center were retrospectively reviewed. The factors predictive of recurrence were determined using both univariate and multivariate analyses considering several clinicopathologic variables.

RESULTS

The median follow-up period was 61.2 months, during which 22 patients (17.5 %) experienced recurrence with 1 death (0.8 %) due to disease. Locoregional recurrence and distant metastasis were found in 20 cases (15.9 %) and 2 cases (1.6 %), respectively. Male gender, aggressive histology, number of lymph node metastases, initial level of T4-off Tg per ng/mL, and ATA risk categories (high risk) were independent risk factors for recurrence. Of note, initial T4-off Tg levels greater than 4.2 ng/mL showed highest sensitivity and specificity in predicting recurrence.

CONCLUSIONS

These results provide useful information regarding the clinical outcomes after therapeutic lateral neck dissection for primary PTC and can be used to identify at-risk patients who need aggressive treatment and intensive surveillance for postoperative recurrence.

HDAC2 provides a critical support to malignant progression of hepatocellular carcinoma through feedback control of mTORC1 and AKT

Aberrant regulation of histone deacetylase 2 (HDAC2) contributes to malignant progression in various cancers, but the underlying mechanism leading to the activation of oncogenic HDAC2 remains unknown. In this study, we show that HDAC2 expression is upregulated in a large cohort of patients with human hepatocellular carcinoma, and that high expression of HDAC2 was significantly associated with poor prognosis of patients with hepatocellular carcinoma. We found that mTORC1/NF-κBp50 signaling is necessary for the growth factor-induced HDAC2 and is sustained in hepatocellular carcinoma, but not in normal hepatic cells. Growth factor-induced mTORC1 activates the nuclear translocation of NF-κBp50, where it binds to the intragenic sequences of the HDAC2 gene and promotes its transcription. Hepatocellular carcinoma tissues derived from chemical-induced mouse and rat liver cancer models validated that mTORC1 activation and NF-κBp50 nuclear translocation are essential for the transcriptional activation of oncogenic HDAC2 in hepatocellular carcinoma. In addition, we demonstrate that HDAC2 is required to maintain mTORC1 activity by stabilizing the mTOR/RAPTOR complex. Elevated expression of HDAC2 triggers a positive feedback loop that activates AKT phosphorylation via the transcriptional modulation of phosphoinositide signaling molecules. Bioinformatics analysis of HDAC2 signature and immunoblot analysis of mesenchymal genes also evidenced that HDAC2 plays a role in the malignant behavior of tumor cells by Snail induction and simultaneously E-cadherin suppression in hepatocellular carcinoma cells. These findings establish a molecular mechanism responsible for the activation of oncogenic HDAC2, which explains how growth factor-induced HDAC2 maintains mitogenic signaling and function during hepatocellular malignant progression and provide a novel strategy for therapeutic intervention in liver cancer. Cancer Res; 74(6); 1728-38. ©2014 AACR.

Respiratory insufficiency and dynamic hyperinflation after rigid bronchoscopy in a patient with relapsing polychondritis -a case report-

Relapsing polychondritis (RP) is an uncommon disease that is characterized by inflammation and destruction of cartilaginous structures. When tracheobronchial tree is involved, respiratory obstructive symptoms can occur. A 35-year-old man, with a previous diagnosis of RP, was scheduled for rigid bronchoscopy to relieve dyspnea, caused by subglottic stenosis. After laser splitting of the subglottic web, the spontaneous respiration of the patient was insufficient, and hypercarbia developed progressively even with assisted ventilation. After 20 minutes of aggressive hyperventilation to reduce end-tidal CO₂ level, sudden extreme tachycardia and hypotension developed. Ventilation rate was reduced and prolonged expiration time was allowed to alleviate a near-tampon status from dynamic hyperinflation. After the hemodynamic status was stabilized, the patient was transferred to the ICU for mechanical ventilation. He received ICU care for 30 days, and now, he was on supportive care on a ward, considering Y stent insertion to prevent luminal collapse from tracheobronchomalacia.

Down-regulation of mortalin exacerbates Aβ-mediated mitochondrial fragmentation and dysfunction

Mitochondrial dynamics greatly influence the biogenesis and morphology of mitochondria. Mitochondria are particularly important in neurons, which have a high demand for energy. Therefore, mitochondrial dysfunction is strongly associated with neurodegenerative diseases. Until now various post-translational modifications for mitochondrial dynamic proteins and several regulatory proteins have explained complex mitochondrial dynamics. However, the precise mechanism that coordinates these complex processes remains unclear. To further understand the regulatory machinery of mitochondrial dynamics, we screened a mitochondrial siRNA library and identified mortalin as a potential regulatory protein. Both genetic and chemical inhibition of mortalin strongly induced mitochondrial fragmentation and synergistically increased Aβ-mediated cytotoxicity as well as mitochondrial dysfunction. Importantly we determined that the expression of mortalin in Alzheimer disease (AD) patients and in the triple transgenic-AD mouse model was considerably decreased. In contrast, overexpression of mortalin significantly suppressed Aβ-mediated mitochondrial fragmentation and cell death. Taken together, our results suggest that down-regulation of mortalin may potentiate Aβ-mediated mitochondrial fragmentation and dysfunction in AD.

TNFα-induced miR-130 resulted in adipocyte dysfunction during obesity-related inflammation

Adipocytes are continuously stimulated by proinflammatory cytokines such as TNFα, which cause adipocyte dysfunction by facilitating the inflammatory response. Although miR-130 was reported to be an important regulator of adipogenesis by targeting PPARγ mRNA, little is known about the mechanisms regulating miR-130 expression during the proinflammatory response. Here, we examined miR-130 levels in white adipose tissue (WAT) from high-fat diet (HFD) mice and TNFα-stimulated adipocytes. Primary transcripts of miR-130 were increased after TNFα stimulation, indicating that induction of miR-130 during the pro-inflammatory response is regulated by a transcriptional event. A chromatin immunoprecipitation assay showed that p65 binding to the promoter regions of miR-130 was enhanced after TNFα treatment. Taken together, our findings suggest that induction of miR-130 by TNFα is responsible for adipocyte dysfunction.