Antisense oligonucleotide of clusterin mRNA induces apoptotic cell death and prevents adhesion of rat ASC-17D Sertoli cells

UV-induced skin's green autofluorescence is a biomarker for both non-invasive evaluations of the dosages of UV exposures of the skin and non-invasive prediction of UV-induced skin damage

It is crucial to discover biomarkers for non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period, and for non-invasive prediction of UV-induced skin damage. Our current study has obtained findings: UVB exposures produced dose-dependent increases in skin's green autofluorescence (AF) intensity of mice, which were significantly associated with the UVB dosages. The UVC-induced green AF increases were dose dependent, which were highly associated with the UVC dosages. Moreover, both previous reports and our current study have collectively shown significant association between UVB/UVC dosages and UVB/UVC-induced skin damage. Collectively, our study has indicated that the UVB/UVC-induced skin's AF are first biomarkers for both non-invasive evaluations of the dosages of UV exposures to a person during post-UV exposure period and non-invasive and label-free prediction of UVB/UVC-induced skin damage.

The evaluation of a tissue-engineered cardiac patch seeded with hips derived cardiac progenitor cells in a rat left ventricular model

BACKGROUND

Ventricular septal perforation and left ventricular aneurysm are examples of potentially fatal complications of myocardial infarction. While various artificial materials are used in the repair of these issues, the possibility of associated infection and calcification is non-negligible. Cell-seeded biodegradable tissue-engineered patches may be a potential solution. This study evaluated the feasibility of a new left ventricular patch rat model to study neotissue formation in biodegradable cardiac patches.

METHODS

Human induced pluripotent stem cell-derived cardiac progenitor cells (hiPS-CPCs) were cultured onto biodegradable patches composed of polyglycolic acid and a 50:50 poly (l-lactide-co-ε-caprolactone) copolymer for one week. After culturing, patches were implanted into left ventricular walls of male athymic rats. Unseeded controls were also used (n = 10/group). Heart conditions were followed by echocardiography and patches were subsequently explanted at 1, 2, 6, and 9 months post-implantation for histological evaluation.

RESULT

Throughout the study, no patches ruptured demonstrating the ability to withstand the high pressure left ventricular system. One month after transplantation, the seeded patch did not stain positive for human nuclei. However, many new blood vessels formed within patches with significantly greater vessels in the seeded group at the 6 month time point. Echocardiography showed no significant difference in left ventricular contraction rate between the two groups. Calcification was found inside patches after 6 months, but there was no significant difference between groups.

CONCLUSION

We have developed a surgical method to implant a bioabsorbable scaffold into the left ventricular environment of rats with a high survival rate. Seeded hiPS-CPCs did not differentiate into cardiomyocytes, but the greater number of new blood vessels in seeded patches suggests the presence of cell seeding early in the remodeling process might provide a prolonged effect on neotissue formation. This experiment will contribute to the development of a treatment model for left ventricular failure using iPS cells in the future.

Effect of sitagliptin plus metformin on β-cell function, islet integrity and islet gene expression in Zucker diabetic fatty rats

AIM

The combination of metformin and a dipeptidyl peptidase 4 (DPP-4) inhibitor has been shown to be an effective, safe, and well-tolerated treatment for type 2 diabetes. We evaluated β-cell function and morphological changes in islets in Zucker diabetic fatty (ZDF) rats following combined therapy with sitagliptin and metformin and investigated the expression of potentially relevant genes using cDNA microarrays.

METHODS

Nine-week-old ZDF rats were randomly divided into four treatment groups: no treatment (control); sitagliptin; metformin, and sitagliptin plus metformin. After 5 weeks of treatment, an oral glucose tolerance test was performed and plasma levels of active GLP-1 and islet morphology and gene expression were assessed.

RESULTS

Combination therapy reduced fasting glucose and postprandial plasma glucose levels and increased active GLP-1 levels, compared with monotherapy. Combination therapy also increased insulin secretion, the proportion of small islets, and the intensity of insulin staining. Furthermore, it increased the expression of genes involved in cell survival and growth and downregulated apoptosis-associated genes, relative to monotherapy.

CONCLUSIONS

Combination treatment with sitagliptin and metformin preserved β-cell function and β-cell integrity in ZDF rats. This may be associated with the transcriptional activation of anti-apoptotic and pro-survival genes, as well as the suppression of pro-apoptotic genes.

Chapter 9: Oxidative stress in malignant progression: The role of Clusterin, a sensitive cellular biosensor of free radicals

Clusterin/Apolipoprotein J (CLU) gene is expressed in most human tissues and encodes for two protein isoforms; a conventional heterodimeric secreted glycoprotein and a truncated nuclear form. CLU has been functionally implicated in several physiological processes as well as in many pathological conditions including ageing, diabetes, atherosclerosis, degenerative diseases, and tumorigenesis. A major link of all these, otherwise unrelated, diseases is that they are characterized by increased oxidative injury due to impaired balance between production and disposal of reactive oxygen or nitrogen species. Besides the aforementioned diseases, CLU gene is differentially regulated by a wide variety of stimuli which may also promote the production of reactive species including cytokines, interleukins, growth factors, heat shock, radiation, oxidants, and chemotherapeutic drugs. Although at low concentration reactive species may contribute to normal cell signaling and homeostasis, at increased amounts they promote genomic instability, chronic inflammation, lipid oxidation, and amorphous aggregation of target proteins predisposing thus cells for carcinogenesis or other age-related disorders. CLU seems to intervene to these processes due to its small heat-shock protein-like chaperone activity being demonstrated by its property to inhibit protein aggregation and precipitation, a main feature of oxidant injury. The combined presence of many potential regulatory elements in the CLU gene promoter, including a Heat-Shock Transcription Factor-1 and an Activator Protein-1 element, indicates that CLU gene is an extremely sensitive cellular biosensor of even minute alterations in the cellular oxidative load. This review focuses on CLU regulation by oxidative injury that is the common molecular link of most, if not all, pathological conditions where CLU has been functionally implicated.

Clusterin induces differentiation of pancreatic duct cells into insulin-secreting cells

AIMS/HYPOTHESIS

We recently reported that expression of the gene encoding clusterin (Clu) is upregulated in the regenerating pancreas, particularly in tissues undergoing differentiation. This led us to propose that clusterin participates in the cytodifferentiation of pancreatic tissue, particularly the endocrine islet cells. The aim of this study was to investigate whether clusterin induces the differentiation of duct-lining cells into insulin-secreting cells.

METHODS

We isolated ductal tissue from rat pancreas and cultured it to develop epithelial cell explants for transfection of the Clu cDNA as well as for treatment of clusterin protein.

RESULTS

The number of newly differentiated insulin cells increased 6.9-fold upon Clu overexpression compared with controls. Ins1 mRNA and peptide levels were also increased. Furthermore, glucose-stimulated insulin secretion was observed in the differentiated insulin cells. These cells were immunoreactive for insulin and C-peptide, but negative for other islet hormones and for cytokeratin-20, which indicates a fully differentiated state. Insulin cell differentiation was also increased in a dose-dependent manner by treating duct cells in culture with clusterin, indicating a growth-factor-like action of clusterin in insulin cell differentiation.

CONCLUSIONS/INTERPRETATION

These results suggest that clusterin can be considered as a potential morphogenic factor that promotes differentiation of pancreatic beta cells.

Clusterin protects the lung from leukocyte-induced injury

Clusterin (CLU) is a multifunctional 75- to 80-kDa glycoprotein that is upregulated during cellular stress and might represent a defense mechanism during local cellular damage. Mechanisms discussed are antiapoptotic, antioxidative, and anticomplement properties as well as chaperone-like features protecting stressed proteins. The aim of this study was to investigate potential protective effects of CLU on pulmonary vasculature after in situ PMN activation in isolated rabbit lungs. The experiments were performed on 24 isolated and ventilated rabbit lungs that were perfused with 200 mL of Krebs-Henseleit-10% blood buffer with a constant flow of 150 mL/min in a recirculating system. It was tested whether pretreatment with CLU (2.5 microg/ml; n = 8) or catalase (CAT, 5000 U/ml; n = 8) before N-formyl-Met-Leu-Phe (fMLP; 10(-8) M) injection influenced pulmonary artery pressure (PAP) peak airway pressures (PAW) and edema formation as compared with controls (n = 8). Baseline values of PAP were 9-11 mmHg and PAW 11-13 cm H2O. Application of fMLP resulted in an acute significant (P < 0.01) increase of PAP (48 +/- 29 mmHg) within 2 min in the control group and PAW increased to 35 +/- 7 cm H2O within 30 min. Pretreatment with CLU completely suppressed the PAP and PAW response as a result of the fMLP challenge (P < 0.001), whereas a transient PAW increase up to 27 +/- 15 mmHg was observed after CAT. Complement factor C3a release was suppressed by CAT, whereas CLU blocked the complement cascade at the level of C5b-9 formation. Moreover, generation of thromboxane A(2) was reduced after CLU and CAT. Lung edema occurred in the fMLP group but was absent (P < 0.001) after CLU and CAT treatment. Both CLU and CAT prevented fMLP-induced lung injury. Stabilizing effects of CLU, point towards complement regulating features at the level of the terminal complement sequence. Elevated levels of CLU during inflammation could reflect a compensatory organ protective mechanism. Further studies are required to elucidate the clinical impact of the observed organ-protective properties of CLU.

Histologic changes of nonbiodegradable and biodegradable biomaterials used to repair right ventricular heart defects in rats

OBJECTIVES

Nonbiodegradable synthetic materials have been widely used to repair cardiac defects. Material-related failures, however, such as lack of growth, thrombosis, and infection, do occur. Because a biodegradable scaffold can be replaced by the patient's own cells and will be treated as a foreign body for a limited period, we compared four biodegradable materials (gelatin, polyglycolic acid (PGA), and copolymer made of epsilon-caprolactone and l-lactic acid reinforced with a poly-l-lactide knitted [KN-PCLA] or woven fabric [WV-PCLA]) with a nonbiodegradable polytetrafluoroethylene (PTFE) material. An animal heart model was tested that simulates the in vivo clinical condition to which a synthetic material would be used.

METHODS

The five patches were used to repair transmural defects surgically created in the right ventricular outflow tracts of adult rat hearts (n = 5, each patch group). The PTFE patch group served as a control group. At 8 weeks after implantation, the biomaterials were excised. Patch size, patch thickness, infiltrated cell number, extracellular matrix composition, and patch degradation were evaluated.

RESULTS

The PTFE patch itself did not change in size except for increasing in thickness because of fibroblast and collagen coverage of both its surfaces. Host cells did not migrate into the PTFE biomaterial. In contrast, cells migrated into the biodegrading gelatin, PGA, and KN-PCLA and WV-PCLA scaffolds. Cellular ingrowth per unit patch area was highest in the KN-PCLA patch. The KN-PCLA patch increased modestly in size and thinness. The WV-PCNA patch did not change in size or thickness. Fibroblasts and collagen were the dominant cellular infiltrate and extracellular matrix formed in the biodegrading scaffolds. The in vivo rates of biomaterial degradation, thinning, and expansion were material specific. All the subendocardial patch surfaces were covered with endothelial cells. No thrombi were seen.

CONCLUSIONS

The unique, spongy matrix structure of the PCLA patch favored cell colonization relative to the other patches. The strong, durable outer poly-l-lactide fabric layers in these patches offered physical, biocompatible, and bioresorbable advantages relative to the other biodegradable materials studied. Host cells migrated into all the biomaterials. The cells secreted matrix and formed tissue, which was endothelialized on the endocardial surface. The biomaterial degradation rates and the tissue formation rates were material related. The PCLA grafts hold promise to become a suitable patch for surgical repair.