Autophagy protects against human islet amyloid polypeptide‐associated apoptosis

Aims/Introduction: Islets in type 2 diabetes are characterized by deposition of islet amyloid polypeptide (IAPP) as well as β‐cell dysfunction. The unique amyloidogenic character of human (h)IAPP is associated with cytotoxicity. Autophagy is a ubiquitous system of cellular recycling that contributes to cell survival. Thus, we examined whether autophagy could ameliorate hIAPP‐associated cytotoxicity. Materials and Methods: First, we used a COS‐1 cell model, lacking endogenous IAPP that might affect cytotoxicity related to exogenous hIAPP. Next, we used the mouse β‐cell line, MIN‐6 cells. Both cells were transfected with hIAPP or rat (r)IAPP expression constructs, or transfected with bicistronic vectors expressing green fluorescent protein (GFP) and either hIAPP or rIAPP for flow cytometry analysis. Cell viability and apoptosis markers were studied in relation to chemical or genetic modulation of autophagy. Results: The viability of cells expressing hIAPP was significantly decreased as compared with those expressing rIAPP and the cleavage of pro‐caspase‐3 was elevated in hIAPP‐transfected cells. The formation of autophagosomes and the conversion of microtubule‐associated protein light chain 3B I to II were elevated in hIAPP‐expressing cells. The viability of hIAPP‐expressing cells was increased after treatment with rapamycin, an inducer of autophagy, and decreased after treatment with 3‐methyladenine, an inhibitor of autophagy. In MIN‐6 cells, annexin positive cells were increased by 3‐methyladenine and decreased by rapamycin using flow cytometry. Knocking down of the autophagy protein 5 gene decreased hIAPP‐transfected cell viability. Conclusions: Autophagy is co‐localized with hIAPP expression and it plays a protective role in hIAPP‐associated apoptosis. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00065.x, 2010)     

Increase in cortical pyramidal cell excitability accompanies depression-like behavior in mice: a transcranial magnetic stimulation study

Clinical evidence suggests that cortical excitability is increased in depressives. We investigated its cellular basis in a mouse model of depression. In a modified version of forced swimming (FS), mice were initially forced to swim for 5 consecutive days and then were treated daily with repetitive transcranial magnetic stimulation (rTMS) or sham treatment for the following 4 weeks without swimming. On day 2 through day 5, the mice manifested depression-like behaviors. The next and last FS was performed 4 weeks later, which revealed a 4 week maintenance of depression-like behavior in the sham mice. In slices from the sham controls, excitability in cingulate cortex pyramidal cells was elevated in terms of membrane potential and frequencies of spikes evoked by current injection. Depolarized resting potential was shown to depend on suppression of large conductance calcium-activated potassium (BK) channels. This BK channel suppression was confirmed by measuring spike width, which depends on BK channels. Chronic rTMS treatment during the 4 week period significantly reduced the depression-like behavior. In slices obtained from the rTMS mice, normal excitability and BK channel activity were recovered. Expression of a scaffold protein Homer1a was reduced by the FS and reversed by rTMS in the cingulate cortex. Similar recovery in the same behavioral, electrophysiological, and biochemical features was observed after chronic imipramine treatment. The present study demonstrated that manifestation and disappearance of depression-like behavior are in parallel with increase and decrease in cortical neuronal excitability in mice and suggested that regulation of BK channels by Homer1a is involved in this parallelism.     

High-grade breast cancers include both highly sensitive and highly resistant subsets to cytotoxic chemotherapy

Purpose  

We reported that breast cancers achieving pathological complete response (pCR) or progressive disease (PD) to neoadjuvant chemotherapy (NAC), which are considered exact opposites on the chemosensitivity spectrum, have certain clinicopathological features in common. To determine the highly sensitive and highly resistant subsets to cytotoxic chemotherapy, we evaluated predictive factors for pCR and PD to NAC, and assessed the similarities in these factors.     

Preparation of polymeric nanoparticles of cyclosporin A using infrared pulsed laser

Nanoparticle formation of poorly water-soluble drugs is a means of providing much benefit for improving solubility and bioavailability. We showed that laser irradiation of drugs can be a novel tool for dispersing drug nanoparticles in water. Using our method, we were able to produce nanoparticles containing immunosuppressant drug, cyclosporin A, which shows poor solubility toward water, with high levels of the drug using polyvinyl pyrrolidone and sodium dodecyl sulfate as stabilizing agents. The absence of degradation products was confirmed and the loss of pharmaceutical activity with an inhibitory effect on the interleukin-2 production of Jurkat T cells did not occur. Cyclosporin A nanoparticles showed a spherical shape and their particle size was distributed uniformly around 200 nm. Powder X-ray diffraction analysis suggested that cyclosporin A in the nanoparticles was in an amorphous state. In the measurement of solubility rate, the nanoparticle formulation showed a higher rate than that which had not been processed. At present, although this laser irradiation technology has low productivity, it is expected as a new technology for drug nanoparticle manufacturing together with the development of a new laser device.     

Resection of solitary metachronous lymph node metastasis from hepatocellular carcinoma following transarterial chemotherapy with cisplatin: a case report

A 74-year-old female was found to have a 40-mm liver tumor (in segment VIII) by ultrasonography and was diagnosed with hepatocellular carcinoma (HCC). She underwent liver resection and was stably treated without recurrence for 19 months. A 45-mm extrahepatic tumor was then found during follow-up with enhanced computed tomography and was diagnosed as being a metachronous lymph node (LN) metastasis. Angiography revealed that the metastasis LN was fed by both the right and left gastric arteries. Transarterial chemotherapy with cisplatin was scheduled to control LN metastasis and to prevent intrahepatic metastasis, simultaneously. Blood alteration using coil embolization was performed to isolate the feeding arteries before transarterial chemotherapy with cisplatin powder. The patient was stably treated for 6 months (3 times) and no new intra- or extrahepatic metastatic lesions appeared during the chemotherapy. The patient subsequently underwent systematic LN dissection of the porta hepatis. She was successfully treated, and has remained recurrence-free for almost 5 years.     

Extraskeletal Ewing’s sarcoma in a 67-year-old man

Ewing’s sarcoma is a round-cell tumor that commonly arises from bone, but extraskeletal Ewing’s sarcoma (EES) uncommonly occurs in the deep soft tissue of the extremities or paravertebral region [1], and is morphologically indistinguishable from bone lesions. EES is generally found in adolescents and young adults, although a few cases have been reported in older people [2–4]. The optimal treatment and prognosis are not clearly defined because of the rarity of EES. Because the differential diagnosis includes other round-cell tumors with a cytologic appearance similar to Ewing’s sarcoma, cytogenetic and molecular genetic findings of translocations are important in differentiating EES from other round-cell tumors. We present the case of a 67-year-old man with EES in the thigh whose diagnosis was confirmed histologically and cytogenetically. The patient was informed that data concerning the case would be submitted for publication, and he consented.     

Regulation of synthesis and oxidation of fatty acids by adiponectin receptors (AdipoR1/R2) and insulin receptor substrate isoforms (IRS-1/-2) of the liver in a nonalcoholic steatohepatitis animal model

Nonalcoholic steatohepatitis (NASH) is one of the most frequent causes of abnormal liver dysfunction associated with synthesis and oxidation of fatty acids. Adiponectin receptors (AdipoR1/R2) and insulin receptor substrates (IRS-1/-2) are known as modulators of these fatty acid metabolisms in the liver; however, the regulatory roles of these receptors in the synthesis and oxidation of fatty acids are unclear in the liver of NASH. In this study, we examined the roles of hepatic AdipoR1/R2 and IRS-1/-2 in NASH using an animal model. After feeding a high-fat and high-cholesterol diet to obese fa/fa Zucker rats for 8 weeks, rats showed fatty liver spontaneously with inflammation and fibrosis that are characteristic of NASH. The expression levels of AdipoR1/R2 and IRS-2 were significantly decreased, whereas IRS-1 was significantly increased, in NASH. As a result of the decrease of AdipoR1/R2 expression, the messenger RNA expression levels of genes located downstream of AdipoR1/R2, adenosine monophosphate-activated protein kinase α1/α2, which inhibits fatty acid synthesis, and peroxisome proliferator-activated receptor α, which activates fatty acid oxidation, also decreased. Expression level of sterol regulatory element binding protein-1c was found to be elevated, suggesting the up-regulation of IRS-1, and resulted in increased fatty acid synthesis. Furthermore, increase of forkhead box protein A2 expression was observed, which might be associated with the down-regulation of IRS-2, facilitating fatty acid oxidation. Taken together, increased synthesis and oxidation of fatty acids by up- or down-regulation of AdipoR or IRS may contribute to the progression of NASH. Thus, AdipoR and IRS might be crucially important regulators for the synthesis and oxidation of fatty acids in the liver of NASH.     

细胞角蛋白及其mRNA在根端囊肿上皮衬里中的表达

目的本研究目的是探讨根端囊肿上皮衬里细胞角蛋白及其mRNA的表达情况.方法检测52例根端囊肿衬里上皮的细胞角蛋白(CK8,CK13和CK18)的表达,其中采用免疫组化染色法检测32例上颌根端囊肿和20例下颌根端囊肿;采用原位杂交法检测24例上颌根端囊肿和13例下颌根端囊肿CK-mRNA表达;采用逆转录聚合酶链反应(RT-PCR)法检测24例上颌囊肿.结果上颌根端囊肿中CK8,CK13,CK18阳性的鳞状上皮衬里分别是20例,29例和19例,下颌根端囊肿中表达阳性的分别为10例,20例和11例.上颌根端囊肿中[CK18( )-CK13(-)]3例,[CK18( )-CK13( )]13例,[CK18(-)-CK13( )]13例,而下颌根端囊肿中[CK18( )-CK13(-)]0例,[CK18( )-CK13( )]11例,[CK18(-)-CK13( )]9例.原位杂交显示24例上颌根端囊肿和13例下颌根端囊肿分别有9例和4例囊肿衬里中有CK18-mRNA表达.RT-PCR检测发现CK18-mRNA和CK13-mRNA在正常鼻窦粘膜和牙龈上皮(对照组)及上颌囊肿衬里都有表达.结论CK18-mRNA和CK13-mRNA在根端囊肿鳞状上皮和柱状上皮基本上都有表达.上颌根端囊肿中CK蛋白及其CK18-mRNA表达的不同,可能是囊肿上皮衬里基因型发生转变的结果.