Icariin: A Promising Natural Product in Biomedicine and Tissue Engineering.

Among scaffolds used in tissue engineering, natural biomaterials such as plant-based materials show a crucial role in cellular function due to their biocompatibility and chemical indicators. Because of environmentally friendly behavior and safety, green methods are so important in designing scaffolds. A key bioactive flavonoid of the Epimedium plant, Icariin (ICRN), has a broad range of applications in improving scaffolds as a constant and non-immunogenic material, and in stimulating the cell growth, differentiation of chondrocytes as well as differentiation of embryonic stem cells towards cardiomyocytes. Moreover, fusion of ICRN into the hydrogel scaffolds or chemical crosslinking can enhance the secretion of the collagen matrix and proteoglycan in bone and cartilage tissue engineering. To scrutinize, in various types of cancer cells, ICRN plays a decisive role through increasing cytochrome c secretion, Bax/Bcl2 ratio, poly (ADP-ribose) polymerase as well as caspase stimulations. Surprisingly, ICRN can induce apoptosis, reduce viability and inhibit proliferation of cancer cells, and repress tumorigenesis as well as metastasis. Moreover, cancer cells no longer grow by halting the cell cycle at two checkpoints, G0/G1 and G2/M, through the inhibition of NF-κB by ICRN. Besides, improving nephrotoxicity occurring due to cisplatin and inhibiting multidrug resistance are the other applications of this biomaterial.

Stem cell therapy in the heart: Biomaterials as a key route.

Cardiovascular diseases are one of the main concerns, nowadays causing a high rate of mortality in the world. The majority of conventional treatment protects the heart from failure progression. As a novel therapeutic way, Regenerative medicine in the heart includes cellular and noncellular approaches. Despite the irrefutable privileges of noncellular aspects such as administration of exosomes, utilizing of miRNAs, and growth factors, they cannot reverse necrotic or ischemic myocardium, hence recruiting of stem cells to help regenerative therapy in the heart seems indispensable. Stem cell lineages are varied and divided into two main groups namely pluripotent and adult stem cells. Not only has each of which own regenerative capacity, benefits, and drawbacks, but their turnover also close correlates with the target organ and/or tissue as well as the stage and level of failure. In addition to inefficient tissue integration due to the defects in delivering methods and poor retention of transplanted cells, the complexity of the heart and its movement also make more rigorous the repair process. Hence, utilizing biomaterials can make a key route to tackle such obstacles. In this review, we evaluate some natural products which can help stem cells in regenerative medicine of the cardiovascular system.

Signal transducer and activator of transcription 3 downregulation in J774A.1 cell line as a model of M2 macrophages in tumor microenvironment.

AIM: Tumor-associated macrophages (TAMs) play a decisive role in the regulation of tumor progression by manipulating tumor oncogenesis, angiogenesis, and immune functions within tumor microenvironments. Tumor progression is frequently associated with a phenotypic switch from M1 to M2 in TAM. Activation of signal transducer and activator of transcription 3 (STAT3) in TAM lead to tumor-induced immunosuppression. STAT3 is usually constitutively activated in a variety of malignancies. Consequently, STAT3 has emerged as a promising target for cancer immunotherapy. MATERIALS AND METHODS: In this study, J774A.1 cell line which is an M2 macrophage and overexpress STAT3 was cultured in Dulbecco's Modified Eagle Medium supplemented by fetal bovine serum. Then, the STAT3 silencing was evaluated by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) using oligofectamine containing STAT3 short interfering RNA (siRNA). Oligofectamine containing STAT3 siRNA and control siRNA were added at a final concentration of 100 nM siRNA. The untransfected cells were considered as control group. RESULTS: The semi-quantitative RT-PCR studies showed that J774A.1 cells express a high level of STAT3. Incubation of J774A.1 cells with oligofectamine containing STAT3 siRNA knockdown the STAT3 expression significantly both in 48 and 72 h study; however, the effect was more pronounced in 72 h study. CONCLUSION: The expression of STAT3 in J774A.1 cells confirmed that these cells are M2 macrophage. Moreover, silencing of STAT3 by siRNA delivery using oligofectamine delivery suggests that siRNA delivery using vehicles like nanoliposome could be a useful therapeutic agent in M2 macrophage therapy and its switch to M1 macrophages. This approach could be considered as a novel therapeutic agent for the treatment of all cancers.

Evaluation of toll-like receptor 4 expression in human bone marrow mesenchymal stem cells by lipopolysaccharides from Shigella.

Lipopolysaccharides (LPS) from gram negative bacteria stimulate toll-like receptor 4 (TLR4) expression in immune cells. Recent reports state that bone marrow-derived cells such as mesenchymal stem cells (MSCs) also express TLR proteins. Numerous researches have studied the effect of a number of LPSs on TLR4 expression, but no data exists on the effect of LPSs from different strains of one bacterial genus on TLR4 expression. In this study, we investigate the effects of various concentrations of LPS from different Shigella strains on TLR4 expression in human bone marrow (hBM)-MSCs. At the mRNA level, we have found that untreated hBM-MSCs (control) did not express TLR4 compared to the experimental groups. Cells treated with LPS from Shigella flexneri had the highest expression of TLR4, whereas cells treated with LPS from Shigella sonnei had the lowest expression. We observed that LPSs had a dose-dependent effect on TLR4 expression in all of the treatment groups. ELISA findings for interleukin-6 secretion have confirmed mRNA expression results for all treatment groups. Hence, LPS from S. flexneri can be considered as an optimum LPS to stimulate the immune system for vaccine production against shigellosis. Also, TLR activation in hBM-MSCs can modulate their function such as homing.

Use of an in vitro model in tissue engineering to study wound repair and differentiation of blastema tissue from rabbit pinna.

Rabbit ear wound repair is an accepted model for studies of tissue regeneration, leading to scar less wound repair. It is believed that a specific tissue, blastema, is responsible for such interesting capacity of tissue regeneration. To test this idea further and to elucidate the cellular events happening during the ear wound repair, we designed some controlled experiments in vitro. Small pieces of the ear were punched and washed immediately with normal saline. The tissues were then cultured in the Dulbecco's Modified Eagle(')s Medium, supplemented with fetal bovine serum in control group. As a treatment vitamin A and C was used to evaluate the differentiation potency of the tissue. These tissues were fixed, sectioned, stained, and microscopically studied. Micrographs of electron microscopy provided evidences revealing dedifferentiation of certain cells inside the punched tissues after incubation in tissue culture medium. The histological studies revealed that cells of the tissue (i) can undergo cellular proliferation, (ii) differentiate to epithelial, condrogenic, and osteogenic tissues, and (iii) regenerate the wounds. These results could be used for interpretation of the possible events happening during tissue engineering and wound repair in vitro. An important goal of this study is to create a tissue engineering and tissue banking model, so that in the future it could be used in further blastema tissue studies at different levels.

Xenotransplantation of human adipose derived mesenchymal stem cells in a rodent model of Huntington's disease: motor and non-motor outcomes.

Human mesenchymal stem cells (hMSCs) have been presented as alternative sources of cells to be transplanted into the brain in neurodegenerative disorders. In this regard, the efficacy of hMSCs transplants in reducing motor and non-motor deficits in a quinolinic acid (QA) rat model of Huntington's disease (HD) was tested in the present study. After unilateral lesions in striatum by QA, the isolated and purified hMSCs from liposuction of healthy male donors were transplanted into the damaged striatum of the rats. The cells were stably transfected with a vector containing TurboGFP and JRed to make it possible to trace them after transplantation. Animals were tested by motor and non-motor function tests at different times after the cell transplantation. The hMSCs survived 7 weeks in the brains. An improvement was observed in behavioral tests such as apomophine-induced rotation, hanging wire, and rotarod for the hMSC-treated rats. Anxiety like behaviors were decreased in hMSCs-treated animals when they were examined using open field, elevated plus maze, light and dark box, and novelty suppressed feeding tests. Compared to QA, the hMSCs treatment decreased motor activities. These results confirmed the potential efficacy of hMSCs in treatment of behavioral defects in HD. Generally, the data demonstrated that xenologous transplantation of hMSCs could be considered as an ideal candidate for treatment of neurodegenerative diseases, especially HD.

Histopathological and behavioral assessment of toxin-produced cerebellar lesion: a potent model for cell transplantation studies in the cerebellum.

OBJECTIVE: The cerebellum is a key structure involved in coordinated motor planning, cognition, learning and memory functions. This study presents a permanent model of a toxin produced cerebellar lesion characterized according to contemporary motor and cognitive abnormalities. MATERIALS AND METHODS: In this experimental study, slow administration of quinolinic acid (QA, 5 µl of 200 µmol, 1 µl/minute) in the right cerebellar hemisphere (lobule VI) caused noticeable motor and cognitive disturbances along with cellular degeneration in all treated animals. We assessed behavioral and histopathological studies over ten weeks after QA treatment. The data were analyzed with ANOVA and the student's t test. RESULTS: The QA treated group showed marked motor learning deficits on the rotating rod test (p=0.0001), locomotor asymmetry on the cylinder test (p=0.0001), dysmetria on the beam balance test (p=0.0001), abnormalities in neuromuscular strength on the hang wire test (p=0.0001), spatial memory deficits in the Morris water maze (MWM, p=0.001) and fear conditioned memory on the passive avoidance test (p=0.01) over a ten-week period compared with the control animals. Histopathological analysis showed loss of Purkinje cells (p=0.001) and granular cell density (p=0.0001) in the lesioned hemisphere of the cerebellum. CONCLUSION: Results of the present study show that QA can remove numerous cells which respond to this toxin in hemispheric lobule VI and thus provide a potential model for functional and cell-based studies.