The Effects of Mn2+ on the Proliferation, Osteogenic Differentiation and Adipogenic Differentiation of Primary Mouse Bone Marrow Stromal Cells

The effects of Mn²⁺ on the proliferation, osteogenic and adipogenic differentiation of BMSCs were evaluated by employing MTT, ΔΨm, cell cycle, ALP activity, collagen production, ARS and oil red O stain assays. The results indicated that Mn²⁺ decreased the viability at most concentrations for 24 h, but the viability was increased with prolonging incubation time. Mn²⁺ at the concentrations of 1?×?10^-7 and 1?×?10^-6?mol/L decreased ΔΨm in the BMSCs for 48 h. Mn²⁺ induced G2/M phase cell cycle arrest at tested concentrations. On day 7 and 10, the effect of Mn²⁺ on the osteogenic differentiation depended on concentration, but it inhibited osteogenic differentiation at all tested concentrations for 14 d. The effect of Mn²⁺ on the synthesis of collagen of BMSCs depended on concentration for 7 d, but Mn²⁺ inhibited the synthesis of collagen at all tested concentrations for 10 d. On day 14, Mn²⁺ inhibited the formation of mineralized matrix nodules of BMSCs at all tested concentrations, the inhibitory effect turned to be weaker with prolonging incubation time. Mn²⁺ promoted the adipogenic differentiation of BMSCs at all tested concentrations for 10 d, but had no effect with prolonging incubation time. These findings suggested the effects of Mn²⁺ on the proliferation, osteogenic differentiation and adipogenic differentiation of BMSCs are very complicated, concentration and incubation time are key factors for switching the biological effects of Mn²⁺ from damage to protection.     

Maintenance of human adipose derived stem cell (hASC) differentiation capabilities using a 3D culture

In this study, 3D culture system for human adipose-derived stem cell (hASC) using a BioLevitator as the bioreactor for microcarrier-based cultures was established. During the culturing period, hASCs preferred to grow in crevices between microcarriers and a high viability was maintained even when reaching confluency. Adipogenic or osteogenic differential medium was used to induce hASCs and differential potentials of these cells were compared between 2D and 3D environments via RT-PCR and staining quantifications. CEBP/α gene expression was significant higher in 3D condition at day 21 (P < 0.05). Staining quantification indicates that cells cultured in 3D condition have significant better differentiation potential from day 14 to 21 for both adipogenic and osteogenic lineages (P < 0.01).     

Effect of α, β momorcharin on viability,caspase activity,cytochrome c release and on cytosolic calcium levels in different cancer cell lines

A multitude of plants have been used extensively for the treatment of cancers throughout the world. The protein, α, β momorcharin has been extracted from the plant Momordica charantia (MC), and it possesses anti-cancer and anti-HIV properties similar to the crude water and methanol soluble extract of the plant. This study investigated the anti-cancer effects and the cellular mechanisms of action of α, β momocharin (200–800 μM) on 1321N1, Gos-3, U87-MG, Sk Mel, Corl-23 and Weri Rb-1 cancer cell lines compared to normal healthy L6 muscle cell line measuring cell viability using MTT assay kit, Caspase-3 and 9 activities, cytochrome c release and intracellular free calcium concentrations [Ca²⁺]_i. The results show that α, β momorcharin can evoke significant dose-dependent (P < 0.05; Student’s t test) decreases in the viability (increases in cell death) of 1321N1, Gos-3, U87-MG, Sk Mel, Corl-23 and Weri Rb-1 cancer cell lines compared to healthy L6 muscle cell line and untreated glioma cells. α, β momorcharin (800 μM) also evoked significant (P < 0.05) increases in caspase-3 and 9 activities and cytochrome c release. Similarly, α, β momorcharin elicited significant (P < 0.05) time-dependent elevation in [Ca²⁺]_i in all five glioma cell lines compared to untreated cells. Together, the results have demonstrated that α, β momorcharin can exert its anti-cancer effect on different cancer cell lines by intracellular processes involving an insult to the mitochondria resulting in cellular calcium over loading, apoptosis, cytochrome release and subsequently, cell death.     

Bioactive glass ceramic nanoparticles-coated poly(l-lactic acid) scaffold improved osteogenic differentiation of adipose stem cells in equine

Horses with big bone fractures have low chance to live mainly due to the lake of a proper treatment strategy. We believe that further attempts in equine bone tissue engineering will probably be required to meet all the needs for the lesion therapies. Therefore in this study we aimed to investigate the osteogenic differentiation capacity of equine adipose-derived stem cells (e-ASCs) on nano-bioactive glass (nBGs) coated poly(l-lactic acid) (PLLA) nanofibers scaffold (nBG-PLLA). Using electrospinning technique, PLLA scaffold was prepared successfully and coated with nBGs. Fabricated nanofibers were characterized by MTT, SEM, and FTIR analyses, and then osteogenic differentiation potential of isolated e-ASCs was investigated by the most key osteogenic markers, namely Alizarin red-S, ALP, calcium content and bone related (RUNX2, Collagen I, Osteonectin, and ALP) gene markers. Our results indicated that nBGs was successfully coated on PLLA scaffold and this scaffold had no negative (p > 0.05) effect on cell growth rate as indicated by MTT assay. Moreover, e-ASCs that differentiated on nBGs-PLLA scaffold showed a higher (p < 0.05) ALP activity, more (p < 0.05) calcium content, and higher (p < 0.05) expression of bone-related genes than that on uncoated PLLA scaffold and TCPS. According to the results, a combination of bioceramics and biopolymeric nanofibers hold valuable promising potentials to use for bone tissue engineering application and regenerative medicine.     

Oxytocin activates calcium signaling in rat sensory neurons through a protein kinase C-dependent mechanism

In addition to its well-known effects on parturition and lactation, oxytocin (OT) plays an important role in modulation of pain and nociceptive transmission. But, the mechanism of this effect is unclear. To address the possible role of OT on pain modulation at the peripheral level, the effects of OT on intracellular calcium levels ([Ca²⁺]_i) in rat dorsal root ganglion (DRG) neurons were investigated by using an in vitro calcium imaging system. DRG neurons were grown in primary culture following enzymatic and mechanical dissociation of ganglia from 1- or 2-day-old neonatal Wistar rats. Using the fura-2-based calcium imaging technique, the effects of OT on [Ca²⁺]_i and role of the protein kinase C (PKC)-mediated pathway in OT effect were assessed. OT caused a significant increase in basal levels of [Ca²⁺]_i after application at the doses of 30 nM (n?=?34, p?<?0.01), 100 nM (n?=?41, p?<?0.001) and 300 nM (n?=?46, p?<?0.001). The stimulatory effect of OT (300 nM) on [Ca²⁺]_i was persistent in Ca²⁺-free conditions (n?=?56, p?<?0.01). Chelerythrine chloride, a PKC inhibitor, significantly reduced the OT-induced increase in [Ca²⁺]_i (n?=?28, p?<?0.001). We demonstrated that OT activates intracellular calcium signaling in cultured rat primary sensory neurons in a dose- and PKC-dependent mechanism. The finding of the role of OT in peripheral pain modification may serve as a novel target for the development of new pharmacological strategies for the management of pain.     

Taurine regulation of Ca2+ uptake and (Ca2+ + Mg2+)-ATPase in developing chick B-cells

• 1.1. The objective of the present study was to determine the effect of age and taurine on chick B cell calcium uptake and membrane (Ca²⁺ + Mg²⁺)-ATPase activity in 1–4-week-old chicks.
• 2.2. The calcium uptake rate decreased with age (P < 0.05) and was further decreased by taurine (P < 0.05).
• 3.3. (Ca²⁺ + Mg²⁺)-ATPase activity increased with age (P < 0.05) and was stimulated by taurine (P < 0.05).
• 4.4. The data demonstrate that the flux of calcium across the B-cell membrane changes during early post-hatch development, and that taurine regulates both the influx and efflux of calcium in chick B-cells.

     

Changes in Calcium/Calmodulin Level and Mitochondrial Membrane Potential in Cochlear Neurons of Newborn Mice Infected with Murine Cytomegalovirus

We sought to elucidate the pathogenesis of hearing loss in newborns due to congenital cytomegalovirus. We used the model of murine cytomegalovirus (MCMV) infection and evaluated concentrations of free calcium, calmodulin levels, and mitochondrial membrane potential in cochlear neurons of infected newborn mice. MCMV infection was established by intracranial inoculation of newborn mice with viral suspension (20 μl of MCMV TCID₅₀—10⁴ IU/0.1 ml); the mice in control group were injected 0.9 % NaCl. Concentration of intracellular free calcium concentration ([Ca²⁺] _i ), mitochondrial membrane potential, and the mRNA level of calmodulin (CaM) in the cochlear neurons were evaluated, when the mice were 1 month old. Compared with control group, intracellular [Ca²⁺] _i and CaM mRNA levels significantly (p < 0.05; both comparisons) increased, while the mitochondrial membrane potential significantly (p < 0.05) decreased in the MCMV-infected group. In conclusion, alteration of [Ca²⁺] _i and CaM levels and mitochondrial membrane potentials in cochlear neurons may be the pathological basis of sensorineural hearing loss associated with MCMV infection.     

Red Blood Cell and Serum Magnesium Levels Among Children and Adolescents With Sickle Cell Anemia

This study investigated neurotoxicity of chronic fluorosis in the rat hippocampus. Newly weaning, male, Sprague-Dawley (SD) rats were administered 15, 30, and 60 mg/L sodium fluoride (NaF) solution (fluorine ion concentration 8.25, 16.50, and 33.00 mg/L, respectively), and tap water, for 18 months. The neurotoxicological mechanism was examined with a focus on intracellular calcium overload. Results showed that as the fluoride concentration increased, calcium ion concentration [Ca²⁺], the expression of calcium/calmodulin-dependent protein kinase II α (CaMKIIα), and the expression of catus proto-oncogene protein c-fos (c-fos) all tend to increase. Compared to the control group, Ca²⁺, CaMKIIα, and c-fos significantly increased (P < 0.05) in the moderate-fluoride and the high-fluoride groups. These results indicate that Ca²⁺/CaMKIIα/c-fos channel signal may be the molecular mechanism of central nervous system damage caused by chronic fluoride intoxication. Moreover, elevated Ca²⁺ concentration in the hippocampus may be the initiating factor of neuronal apoptosis induced by fluoride.     

Ghrelin联合三氧化二砷对骨髓间充质干细胞增殖与成骨分化的影响

该文主要探究Ghrelin对三氧化二砷(As2O3)导致的骨髓间充质干细胞(BMSCs)增殖和成骨分化的影响。BMSCs设为对照组、As2O3组、Ghrelin组和联合(As2O3+Ghrelin)组。MTT法检测细胞增殖能力;成骨诱导的第7天和第14天,Real-time PCR及Western blot分别检测成骨相关因子OPN、ALP、RUNX2的mRNA及蛋白表达;第21天,茜素红染色分析钙盐沉积情况。结果显示,细胞增殖能力Ghrelin组>对照组>联合组>As2O3组。与对照组比,As2O3组各因子表达均显著下调(P<0.05),Ghrelin组第14天OPN蛋白表达无显著变化,其余因子均上调(P<0.05);联合组与As2O3组比,第14天OPN基因表达和第7天ALP蛋白表达无显著差异,其余均显著上调(P<0.05)。钙盐沉积:Ghrelin组>对照组>联合组>As2O3组。提示0.5μmol/L As2O3抑制BMSCs增殖和成骨分化,600 ng/mL Ghrelin增强细胞增殖和成骨分化;且Ghrelin能减弱As2O3导致的BMSCs增殖和成骨分化抑制作用。     

Localization of angiotensin-II type 1(AT1) receptors on buffalo spermatozoa: AT1 receptor activation during capacitation triggers rise in cyclic AMP and calcium

The purpose of this study was to determine the role of Ang-II in buffalo spermatozoa; localize angiotensin type 1 (AT1) receptors on the sperm surface and understand the signaling mechanisms involved therein. Immunoblotting and immunocytochemistry using polyclonal Rabbit anti-AT1 (N-10) IgG were performed to confirm the presence of AT1 receptors. Intracellular levels of cyclic adenosine monophosphate (cAMP) were determined by non-radioactive enzyme immunoassay, while that of Calcium [Ca²⁺] were estimated by fluorimetry using Fura2AM dye. The results obtained showed that AT1 receptors were found on the post-acrosomal region, neck and tail regions. Immunoblotting revealed a single protein band with molecular weight of 40 kDa. Ang-II treated cells produced significantly higher level of cAMP compared to untreated cells (22.66 ± 2.4 vs. 10.8 ± 0.98 pmol/10⁸ cells, p < 0.01). The mean levels of Ca²⁺ were also higher in Ang-II treated cells compared to control (117.4 ± 6.1 vs. 61.15 ± 4.2 nmol/10⁸ cells; p < 0.01). The stimulatory effect of Ang-II in both the cases was significantly inhibited in the presence of Losartan (AT1 antagonist; p < 0.05) indicating the involvement of AT1 receptors. Further, presence of neomycin (protein kinase C inhibitor) inhibited significantly the Ang-II mediated rise in Ca²⁺ indicating the involvement of PKC pathway. These findings confirm the presence of AT1 receptors in buffalo spermatozoa and that Ang-II mediates its actions via the activation of these receptors. Ang-II stimulates the rise in intracellular levels of cAMP and Ca²⁺ during capacitation.     

Doxorubicin Induces Sarcoplasmic Reticulum Calcium Regulation Dysfunction via the Decrease of SERCA2 and Phospholamban Expressions in Rats

This study aims to explore the changes in calcium regulation in the sarcoplasmic reticulum (SR) during doxorubicin (DOX) treatment. Sprague–Dawley rats were treated with intravenous DOX (1.5 mg/kg) twice weekly for 12 treatments. The hemodynamic changes, myocardial oxidative stress, levels of cardiac toxicity markers, and calcium handling of the myocardial SR were observed. When the accumulation of DOX reached 12 mg/kg, (1) heart weight, left ventricular mass, and lung congestion increased significantly, and ascites appeared; (2) SBP, DBP, MAP, +dP/dt, ?dP/dt, and LVSP decreased significantly, and LVEDP increased (p < 0.01); (3) the iNOS activity and MDA and NO concentrations significantly increased, while the SOD decreased (p < 0.05 or 0.01); (4) the serum level of the AST, LDH CPK, cTnI, and BNP increased significantly (p < 0.01); (5) during DOX treatment, the rat SR Ca²⁺ absorption function and Ca²⁺-stimulated ATPase activity declined dramatically, as did the SERCA2 and phospholamban levels (p < 0.01). As expected, all these changes became evident with DOX accumulation in vivo (p < 0.05 or 0.01). In conclusion, DOX induces SR calcium regulation dysfunction via the decrease of SERCA2 and phospholamban expressions in rats.     

Self-healing and injectable hybrid hydrogel for bone regeneration of femoral head necrosis and defect

Background

HA modified by bisphosphonate (BP) (HA-BP) was synthesized by chemical reaction and possessed promising properties such as self-healing, injection ability, and strong adhesion. The main aim of this study was to confirm its role in promoting osteogenic differentiation in vitro and bone regeneration in vivo.

Oxidative Stress and Ca2+ Signals Involved on Cadmium-Induced Apoptosis in Rat Hepatocyte

Cadmium (Cd) is an important industrial and environmental pollutant. In animals, the liver is the major target organ of Cd toxicity. In this study, rat hepatocytes were treated with 2.5～10 μM Cd for various durations. Studies on nuclear morphology, chromatin condensation, and apoptotic cells demonstrate that Cd concentrations ranging within 2.5～10 μM induced apoptosis. The early-stage marker of apoptosis, i.e., decreased mitochondrial membrane potential, was observed as early as 1.5 h at 5 μM Cd. Significant (P?P?2+ concentration ([Ca²⁺] _i ) of Cd-exposed cells significantly increased (P?2+] _i may play an important role in apoptosis. Overall, these results showed that oxidative stress and Ca²⁺ signaling were critical mediators of the Cd-induced apoptosis of rat hepatocytes.     

Role of ecto-NTPDases on UDP-sensitive P2Y(6) receptor activation during osteogenic differentiation of primary bone marrow stromal cells from postmenopausal women

This study aimed at investigating the expression and function of uracil nucleotide‐sensitive receptors (P2Y₂, P2Y₄, and P2Y₆) on osteogenic differentiation of human bone marrow stromal cells (BMSCs) in culture. Bone marrow specimens were obtained from postmenopausal female patients (68 ± 5 years old, n = 18) undergoing total hip arthroplasty. UTP and UDP (100 µM) facilitated osteogenic differentiation of the cells measured as increases in alkaline phosphatase (ALP) activity, without affecting cell proliferation. Uracil nucleotides concentration‐dependently increased [Ca²⁺]_i in BMSCs; their effects became less evident with time (7 > 21 days) of the cells in culture. Selective activation of P2Y₆ receptors with the stable UDP analog, PSB 0474, mimicked the effects of both UTP and UDP, whereas UTPγS was devoid of effect. Selective blockade of P2Y₆ receptors with MRS 2578 prevented [Ca²⁺]_i rises and osteogenic differentiation caused by UDP at all culture time points. BMSCs are immunoreactive against P2Y₂, P2Y₄, and P2Y₆ receptors. While the expression of P2Y₆ receptors remained fairly constant (7～21 days), P2Y₂ and P2Y₄ became evident only in less proliferative and more differentiated cultures (7 < 21 days). The rate of extracellular UTP and UDP inactivation was higher in less proliferative and more differentiated cell populations. Immunoreactivity against NTPDase1, ‐2, and ‐3 rises as cells differentiate (7 < 21 days). Data show that uracil nucleotides are important regulators of osteogenic cells differentiation predominantly through the activation of UDP‐sensitive P2Y₆ receptors coupled to increases in [Ca²⁺]_i. Endogenous actions of uracil nucleotides may be balanced through specific NTPDases determining whether osteoblast progenitors are driven into proliferation or differentiation. J. Cell. Physiol. 227: 2694–2709, 2012. © 2011 Wiley Periodicals, Inc.     

Mechanisms associated to impaired activity of cardiac P-type ATPases in endothelial nitric oxide synthase knockout mice

The effect of long-lasting in vivo restriction of nitric oxide (NO) bioavailability on cardiac and renal P-type ATPases critical for intracellular ion homeostasis is controversial. Previous work has shown in eNOS knockout (eNOS^?/?) mice hearts that Na⁺/K⁺- and Ca²⁺-ATPase activities were depressed but the underlying mechanisms are still unclear. The goal of this study was to characterize potential alterations responsible for impaired enzyme activity in eNOS^?/? mice. Na⁺/K⁺-ATPase activity from crude preparations of adult male eNOS^?/? mice hearts and kidneys was reduced compared with wild-type animals (32 %, p?<?0.05 and 16 %, p?<?0.0001, respectively). Immunoblot analysis showed that although the expression of the predominant (or exclusive, for the kidney) Na⁺/K⁺-ATPase α1 isoform was not significantly changed, there was an important downregulation of the less abundant α2 isoform in the heart (57 %, p?<?0.0001). In addition, although cardiac Ca²⁺-ATPase activity was unaltered, the expression of sarco/endoplasmic reticulum Ca²⁺-ATPase 2 protein in eNOS^?/? mice was very high (290 % compared with wild-type animals, p?<?0.0001) without any significant change in phospholamban expression. Consistent with these findings, the content of cardiac and renal free sulfhydryl groups, essential for the catalytic function of such ATPases, was decreased (23 %, p?<?0.01 and 35 %, p?<?0.05, respectively). Altogether, the present results suggest that the absence of eNOS promotes a compartmentalized altered redox balance that affects the activity and expression of ion transport ATPases.     

Dose‐dependent effects of nicotine on proliferation and differentiation of human bone marrow stromal cells and the antagonistic action of vitamin C

A range of biological and molecular effects caused by nicotine are considered to effect bone metabolism. Vitamin C functions as a biological antioxidant. This study was to evaluate the in vitro effects of nicotine on human bone marrow stromal cells and whether Vitamin C supplementation show the antagonism action to high concentration nicotine. We used CCK‐8, alkaline phosphatase (ALP) activity assay, Von Kossa staining, real‐time polymerase chain reaction and Western Blot to evaluate the proliferation and osteogenic differentiation. The results indicated that the proliferation of BMSCs increased at the concentration of 50, 100 ng/ml, got inhibited at 1,000 ng/ml. When Vitamin C was added, the OD for proliferation increased. For ALP staining, we found that BMSCs treated with 50 and 100 ng/ml nicotine showed a higher activity compared with the control, and decreased at the 1,000 ng/ml. Bone morphogenetic protein‐2 (BMP‐2) expression and the calcium depositions decreased at 100 and 1,000 ng/ml nicotine, while the addition of Vitamin C reversed the down regulation. By real‐time PCR, we detected that the mRNA expression of collagen type I (COL‐I) and ALP were also increased in 50 and 100 ng/ml nicotine groups (P < 0.05), while reduced at 1,000 ng/ml (P < 0.05). When it came to osteocalcin (OCN), the changes were similar. Taken all together, it is found that nicotine has a two‐phase effect on human BMSCs, showing that low level of nicotine could promote the proliferation and osteogenic differentiation while the high level display the opposite effect. Vitamin C could antagonize the inhibitory effect of higher concentration of nicotine partly. J. Cell. Biochem. 114: 1720–1728, 2013. © 2013 Wiley Periodicals, Inc.     

Magnesium Ions Promote the Biological Behaviour of Rat Calvarial Osteoblasts by Activating the PI3K/Akt Signalling Pathway

Magnesium has been investigated as a biodegradable metallic material. Increased concentrations of Mg²⁺ around magnesium implants due to biodegradation contribute to its satisfactory osteogenic capacity. However, the mechanisms underlying this process remain elusive. We propose that activation of the PI3K/Akt signalling pathway plays a role in the Mg²⁺-enhanced biological behaviours of osteoblasts. To test this hypothesis, 6, 10 and 18 mM Mg²⁺ was used to evaluate the stimulatory effect of Mg²⁺ on osteogenesis, which was assessed by evaluating cell adhesion, cell viability, ALP activity, extracellular matrix mineralisation and RT-PCR. The expression of p-Akt was also determined by western blotting. The results showed that 6 and 10 mM Mg²⁺ elicited the highest stimulatory effect on cell adhesion, cell viability and osteogenic differentiation as evidenced by cytoskeletal staining, MTT assay results, ALP activity, extracellular matrix mineralisation and expression of osteogenic differentiation-related genes. In contrast, 18 mM Mg²⁺ had an inhibitory effect on the behaviour of osteoblasts. Furthermore, 10 mM Mg²⁺ significantly increased the phosphorylation of Akt in osteoblasts. Notably, the aforementioned beneficial effects produced by 10 mM Mg²⁺ were abolished by blocking the PI3K/Akt signalling pathway through the addition of wortmannin. In conclusion, these results demonstrate that 6 mM and 10 mM Mg²⁺ can enhance the behaviour of osteoblasts, which is at least partially attributed to activation of the PI3K/Akt signalling pathway. Furthermore, a high concentration (18 mM Mg²⁺) showed an inhibitory effect on the biological behaviour of osteoblasts. These findings advance the understanding of cellular responses to biodegradable metallic materials and may attract greater clinical interest in magnesium.