Nuclear proteins and diabetic retinopathy: a review.

Diabetic retinopathy (DR) is an eye disease that causes blindness and vision loss in diabetic. Risk factors for DR include high blood glucose levels and some environmental factors. The pathogenesis is based on inflammation caused by interferon and other nuclear proteins. This review article provides an overview of DR and discusses the role of nuclear proteins in the pathogenesis of the disease. Some core proteins such as MAPK, transcription co-factors, transcription co-activators, and others are part of this review. In addition, some current advanced treatment resulting from the role of nuclear proteins will be analyzes, including epigenetic modifications, the use of methylation, acetylation, and histone modifications. Stem cell technology and the use of nanobiotechnology are proposed as promising approaches for a more effective treatment of DR.

Inhibition of endogenous hydrogen sulfide production suppresses the growth of nasopharyngeal carcinoma cells.

Hydrogen sulfide (H2 S) has been widely recognized as one of gasotransmitters. Endogenous H2 S plays a crucial role in the progression of cancer. However, the effect of endogenous H2 S on the development of nasopharyngeal carcinoma (NPC) is still unknown. In this study, aminooxyacetic acid (AOAA, an inhibitor of cystathionine-ß-synthase), dl-propargylglycine (PAG, an inhibitor of cystathionine-γ-lyase), and l-aspartic acid (l-Asp, an inhibitor of 3-mercaptopyruvate sulfurtransferase) were adopted to detect the role of endogenous H2 S in NPC growth. The results indicated that the combine (PAG + AOAA + l-Asp) group had higher inhibitory effect on the growth of NPC cells than the PAG, AOAA, and l-Asp groups. There were similar trends in the levels of apoptosis and reactive oxygen species (ROS). In addition, the combine group exhibited lower levels of phospho (p)-extracellular signal-regulated protein kinase but higher expressions of p-p38 and p-c-Jun N-terminal kinase than those in the AOAA, PAG, and l-Asp groups. Furthermore, the combine group exerted more potent inhibitory effect on NPC xenograft tumor growth without obvious toxicity. In summary, suppression of endogenous H2 S generation could dramatically inhibit NPC growth via the ROS/mitogen-activated protein kinase pathway. Endogenous H2 S may be a novel therapeutic target in human NPC cells. Effective inhibitors for H2 S-producing enzymes could be designed and developed for NPC treatment.

Role of hydrogen sulphide in physiological and pathological angiogenesis.

The role of hydrogen sulphide (H2 S) in angiogenesis has been widely demonstrated. Vascular endothelial growth factor (VEGF) plays an important role in H2 S-induced angiogenesis. H2 S promotes angiogenesis by upregulating VEGF via pro-angiogenic signal transduction. The involved signalling pathways include the mitogen-activated protein kinase pathway, phosphoinositide-3 kinase pathway, nitric oxide (NO) synthase/NO pathway, signal transducer and activator of transcription 3 (STAT3) pathway, and adenosine triphosphate (ATP)-sensitive potassium (KATP ) channels. H2 S has been shown to contribute to tumour angiogenesis, diabetic wound healing, angiogenesis in cardiac and cerebral ischaemic tissues, and physiological angiogenesis during the menstrual cycle and pregnancy. Furthermore, H2 S can exert an anti-angiogenic effect by inactivating Wnt/ß-catenin signalling or blocking the STAT3 pathway in tumours. Therefore, H2 S plays a double-edged sword role in the process of angiogenesis. The regulation of H2 S production is a promising therapeutic approach for angiogenesis-associated diseases. Novel H2 S donors and/or inhibitors can be developed in the treatment of angiogenesis-dependent diseases.

Role of Hydrogen Sulfide in Oral Disease.

Oral diseases are among the most common human diseases yet less studied. These diseases affect both the physical, mental, and social health of the patients resulting in poor quality of life. They affect all ages, although severe stages are mostly observed in older individuals. Poor oral hygiene, genetics, and environmental factors contribute enormously to the development and progression of these diseases. Although there are available treatment options for these diseases, the recurrence of the diseases hinders their efficiency. Oral volatile sulfur compounds (VSCs) are highly produced in oral cavity as a result of bacteria activities. Together with bacteria components such as lipopolysaccharides, VSCs participate in the progression of oral diseases by regulating cellular activities and interfering with the immune response. Hydrogen sulfide (H2S) is a gaseous neurotransmitter primarily produced endogenously and is involved in the regulation of cellular activities. The gas is also among the VSCs produced by oral bacteria. In numerous diseases, H2S have been reported to have dual effects depending on the cell, concentration, and donor used. In oral diseases, high production and subsequent utilization of this gas have been reported. Also, this high production is associated with the progression of oral diseases. In this review, we will discuss the production of H2S in oral cavity, its interaction with cellular activities, and most importantly its role in oral diseases.

Nanomedicine: A Promising Way to Manage Alzheimer's Disease.

Alzheimer's disease (AD) is a devastating disease of the aging population characterized by the progressive and slow brain decay due to the formation of extracellular plaques in the hippocampus. AD cells encompass tangles of twisted strands of aggregated microtubule binding proteins surrounded by plaques. Delivering corresponding drugs in the brain to deal with these clinical pathologies, we face a naturally built strong, protective barrier between circulating blood and brain cells called the blood-brain barrier (BBB). Nanomedicines provide state-of-the-art alternative approaches to overcome the challenges in drug transport across the BBB. The current review presents the advances in the roles of nanomedicines in both the diagnosis and treatment of AD. We intend to provide an overview of how nanotechnology has revolutionized the approaches used to manage AD and highlight the current key bottlenecks and future perspective in this field. Furthermore, the emerging nanomedicines for managing brain diseases like AD could promote the booming growth of research and their clinical availability.

Effects of total flavonoids from Drynariae Rhizoma prevent bone loss in vivo and in vitro.

Estrogen deficiency is one of the major causes of osteoporosis in postmenopausal women. Drynariae Rhizoma is a widely used traditional Chinese medicine for the treatment of bone diseases. In this study, we investigated the therapeutic effects of the total Drynariae Rhizoma flavonoids (DRTF) on estrogen deficiency-induced bone loss using an ovariectomized rat model and osteoblast-like MC3T3-E1 cells. Our results indicated that DRTF produced osteo-protective effects on the ovariectomized rats in terms of bone loss reduction, including decreased levels of bone turnover markers, enhanced biomechanical femur strength and trabecular bone microarchitecture deterioration prevention. In vitro experiments revealed that the actions of DRTF on regulating osteoblastic activities were mediated by the estrogen receptor (ER) dependent pathway. Our data also demonstrated that DRTF inhibited osteoclastogenesis via up-regulating osteoprotegrin (OPG), as well as down-regulating receptor activator of NF-κB ligand (RANKL) expression. In conclusion, this study indicated that DRTF treatment effectively suppressed bone mass loss in an ovariectomized rat model, and in vitro evidence suggested that the effects were exerted through actions on both osteoblasts and osteoclasts.

The importance of the prenyl group in the activities of osthole in enhancing bone formation and inhibiting bone resorption in vitro.

Osteoporosis treatment always aimed at keeping the balance of bone formation and bone resorption. Recently, prenyl group in natural products has been proposed as an active group to enhance the osteogenesis process. Osthole has both the prenyl group and bone-protective activities, but the relationship is still unknown. In this study we found that osthole exerted a potent ability to promote proliferation and osteogenic function of rat bone marrow stromal cells and osteoblasts, including improved cell viability, alkaline phosphatase activity, enhanced secretion of collagen-I, bone morphogenetic protein-2, osteocalcin and osteopontin, stimulated mRNA expression of insulin-like growth factor-1, runt-related transcription factor-2, osterix, OPG (osteoprotegerin), RANKL (receptor activator for nuclear factor-κB ligand), and the ratio of OPG/RANKL, as well as increasing the formation of mineralized nodules. However, 7-methoxycoumarin had no obvious effects. Osthole also inhibited osteoclastic bone resorption to a greater extent than 7-methoxycoumarin, as shown by a lower tartrate-resistant acid phosphatase activity and lower number and smaller area of resorption pits. Our findings demonstrate that osthole could be a potential agent to stimulate bone formation and inhibit bone resorption, and the prenyl group plays an important role in these bone-protective effects.

Icariin stimulates the osteogenic differentiation of rat bone marrow stromal cells via activating the PI3K-AKT-eNOS-NO-cGMP-PKG.

Icariin, a prenylated flavonol glycoside isolated from Epimedii herba, has been found to be a potent stimulator of osteogenic differentiation and has potential application in preventing bone loss. However, the signaling pathway underlying its osteogenic effect remains unclear. We hypothesized that the osteogenic activity of icariin is related to the nitric oxide (NO) signal pathway and PI3K/AKT pathway in its upstream. Rat bone marrow stromal cells (rBMSCs) were cultured in osteogenic medium and treated with icariin or together with L-NAME, ODQ, PDE5, and/or LY294002 (the inhibitor of NOS, sGC, cGMP, and PI3K respectively), and effects were examined on the expression of signal messengers (NOS, NO, sGC, cGMP, PKG and PI3K) and the levels of osteogenic markers (alkaline phosphatase or ALP, osteocalcin and calcified nodules). It was found that icariin dose-dependently increased ALP activity, and treatment at the optimal concentration (10(-5)M) increased NOS activity, iNOS and eNOS expression, NO production, sGC and cGMP contents and PKG expression besides the phosphorylation of AKT. The addition of L-NAME, ODQ and PDE5 significantly inhibited the icariin effects on above markers respectively. The addition of LY294002 decreased the p-AKT level, NOS activity, eNOS expression and NO production significantly, but had no significant effect on iNOS expression. The addition of any of the four inhibitors also abolished the osteogenic effect of icariin on rBMSCs as indicated by ALP activity, osteocalcin synthesis, calcium deposition and the number and areas of calcified nodules. These results suggest that the osteogenic effect of icariin involves the PI3K-AKT-eNOS-NO-cGMP-PKG signal pathway. Furthermore, dosage response studies showed that icariin at 10(-6)M (a physiologically achievable concentration in vivo) also activated this signal pathway.

Antiosteoporosis effect of radix scutellariae extract on density and microstructure of long bones in tail-suspended sprague-dawley rats.

Radix Scutellariae (RS), a medicinal herb, is extensively employed in traditional Chinese medicines and modern herbal prescriptions. Two major flavonoids in RS were known to induce osteoblastic differentiation and inhibit osteoclast differentiation, respectively. This study aimed to investigate the effect of Radix Scutellariae extract (RSE) against bone loss induced by mechanical inactivity or weightlessness. A hindlimb unloading tail-suspended rat model (TS) was established to determine the effect of RSE on bone mineral density and bone microarchitecture. Treatment of RSE at 50 mg/kg/day and alendronate (ALE) at 2 mg/kg/day as positive control for 42 days significantly increased the bone mineral density and mechanical strength compared with TS group. Enhanced bone turnover markers by TS treatment were attenuated by RSE and ALE administration. Deterioration of bone trabecula induced by TS was prevented. Moreover, both treatments counteracted the reduction of bone volume fraction, trabecular thickness and number, and connectivity density. In conclusion, RSE was demonstrated for the first time to prevent osteoporosis induced by TS treatment, which suggests the potential application of RSE in the treatment of disuse-induced osteoporosis.

A systematic review of the efficacy and pharmacological profile of Herba Epimedii in osteoporosis therapy.

The purpose of this systematic review is to assess the efficacy and pharmacological profiles of Herba Epimedii in osteoporosis therapy. Four databases were extensively retrieved that include two Chinese electronic databases (VIP Information and CNKI) and two English electronic databases (CA and MEDLINE). Herba Epimedii has been an important traditional herbal medicine for centuries in China and other Asian countries. Recently, quite a few pharmacological effects of Herba Epimedii, its extracts and active components have been identified that include improving bone health and cardiovascular function, regulating hormone level, modulating immunological function, and inhibiting tumor growth. The anti-osteoporosis activity of Herba Epimedii and its extracts have attracted world-wide attention. The literature search has revealed that a lot of studies have recently been carried out related to the bone-strengthening activity of Herba Epimedii and some of its active compounds, such as total flavonoids and icariin. Pharmacokinetic and toxicity studies have confirmed the efficacy and safety of Herba Epimedii and its most abundant active component icariin, while only a few authors have reviewed the anti-osteoporosis properties of the plants. So we summarize the work of various investigators on the effects of Herba Epimedii, its extracts and active components against osteoporosis. The underlying mechanism of osteoprotective action, derivatives of icariin, animal models and cell lines used in the research were also reviewed in this paper.

[Effects of naringin on proliferation, differentiation and maturation of rat calvarial osteoblasts in vitro].

OBJECTIVE: To investigate the effects of naringin on the proliferation, differention and maturaion of rat calvarial osteoblasts (ROB). METHOD: Segregated neonatal SD rat skull, enzyme digestion to obtain ROB. The culture medium was replaced every three days. Serial subcultivation proceeded when cells covered with 80% culture dish. Naringin supplemented into the culture at 1 x 10(-4), 1 x 10(-5), 1 x 10(-6), 1 x 10(-7) mol x L(-1) respectively. MTT method was adopted in proliferation analysis and the activity of ALP was examined after induced 9 days. Search the best concentration and supplemented into the medium, then the osteogenic differentiation markers including the secretion amount of osteocalcin, osteopontin and bone morphogenetic protein-2 were compared between the naringin-supplemented group and the control. Total RNA was isolated and the mRNA level of bFGF, IGF-1, Runx-2, Osterix, ERa and ERbeta was investigated by Real time RT-PCR. Total protein also was isolated and the expression ERa, ERbeta and collagen I was examined by Western blot. After the addition of ICI 182.780, an inhibitor of the estrogen signal pathway, these index also was examined and the changes were compared. RESULT: The ROB proliferation was motivated by naringin dose-dependently. And it evidently leads to osteogenic process and maturation. 1 x 10(-5) mol x L(-1) is the best concentration. Naringin improved the secretion of osteocalcin, osteopontin, bone morphogenetic protein-2 and collagen I significantly. Besides, it can also enhanced the mRNA level of bFGF, IGF-1, Runx-2, Osterix, ERalpha and ERbeta. While all these effects can be restrained by ICI 182.780. CONCLUSION: The naringin with final concentration of 1 x 10(-5) mol x L(-1) enhances the osteogenic differentiation and maturation of ROB significantly, while the promoting effects vanished after the addition of ICI 182.780. These results suggesting that naringin is one of the phytoestrogens and have the activity of bone formation may via estrogen signal pathway, it can be developed into a new drug for osteoporosis therapy.

[Effects of icariin on the proliferation, differentiation and maturation of rat calvarial osteoblasts in vitro].

OBJECTIVE: To investigate the effects of icariin on the proliferation, differentiation and maturation of rat calvarial osteoblasts (ROB). METHODS: Segregated neonatal SD rat skull,enzyme digestion to obtain ROB. The culture medium was replaced every three days. Serial subcultivation proceeded when cells covered with 80% culture dish. Icariin was added into the culture at 1 x 10(-4), 1 x 10(-5), 1 x 10(-6), 1 x 10(-7) mol/L respectively. MTT method was adopted in proliferation analysis. The activity of ALP was assayed after 9 days' induced. Optimal concentration icariin was added into the medium, then the osteogenic differentiation markers including mineralized bone nodules, CFU-F(ALP) were compared between the icariin-added group and the control. Total RNA was isolated and the gene expressions of Runx-2 and Osterix were investigated by Real Time RT-PCR. Total protein was also isolated and the secretion of collagen I was examined by Western-blot. RESULTS: The ROB proliferation was inhibited by icariin in a dose-dependent manner. But it evidently led to osteogenic process and maturation. 1 x 10(-5) mol/L was the best concentration. Icariin improved the secretion of collagen I, CFU-F(ALP) amounts and mineralized nodules significantly. It also enhanced the mRNA level of Runx-2 and Osterix. CONCLUSION: The icariin with final concentration of 1 x 10(-5) mol/L can enhance the osteogenic differentiation and maturation of ROB significantly, suggesting that icariin has the activity of inducing bone formation, it has the potential to be developed into a new drug of anti-osteoporosis.

[The changes of iNOS and NO in the osteogenic differentiation process of rat bone marrow stromal cells promoted by icariside II].

This study is to investigate the effects on the expression of iNOS and production of NO in the osteogenic differentiation process of rat bone marrow stromal cells (rBMSCs) by icariside II. rBMSCs were cultured by adherence screening method. When the culture dishes were covered with 80% cells, the osteogenic induced cultures were adopted. Icariside II was supplemented into the culture at 1 x 10(-5) mol x L(-1). The activity of iNOS, content of NO and osteogenic differentiation markers including alkaline phosphatase (ALP) activity, CFU-FALP and mineralized bone nodules were compared among the icariside II-supplemented group, L-NMAE group, icariside II + L-NAME group and the control. Total RNA was isolated and the gene expression of iNOS, Osterix and Runx-2 was investigated by real-time PCR. Total protein was also isolated and the secretion of iNOS and collagen I was examined by Western blotting. Icariside II can significantly improved ALP activity, CFU-FALP amount and mineralized nodules. Besides, the mRNA level of factors related to the osteogenic differentiation includes Osterix and Runx-2 also enhanced. The secretion of collagen I also promoted significantly. But all of these effects can be inhibited by L-NAME which can specifically inhibit the activity of iNOS. Icariside II enhances the osteogenic differentiation of rBMSCs significantly, but if the activity of iNOS was blocked by L-NAME, the osteogenic differentiation markers decrease accompanied with iNOS and NO decrease, suggesting that icariside II stimulates the osteogenic differentiation via enhancing the activity of iNOS and promoting the generation of NO.

Icariin is more potent than genistein in promoting osteoblast differentiation and mineralization in vitro.

There has been a strong interest in searching for natural therapies for osteoporosis. Genistein, an isoflavone abundant in soy, and icariin, a prenylated flavonol glycoside isolated from Epimedium Herb, have both been identified to exert beneficial effects in preventing postmenopausal bone loss. However, the relative potency in osteogenesis between the individual phytoestrogen flavonoids remains unknown. The present study compared ability of genistein and icariin in enhancing differentiation and mineralization of cultured rat calvarial osteoblasts in vitro. Dose-dependent studies in osteoblast differentiation measuring alkaline phosphatase (ALP) activity revealed optimal concentrations of genistein and icarrin for stimulating osteogenesis to be both at 10(-5) M. Time course studies comparing the two compounds both at 10(-5) M demonstrated that icariin treatment always produced higher ALP activity, more and larger areas of CFU-F(ALP) colonies and mineralized nodules, more osteocalcin secretion, and calcium deposition, and a higher level of mRNA expression of osteogenesis-related genes COL1α2, BMP-2, OSX, and RUNX-2. However, they inhibited the proliferation of osteoblasts to a similar degree. In conclusion, although future in vivo studies are required to investigate whether icariin is more efficient in improving bone mass and/or preventing bone loss, our in vitro studies have demonstrated that icariin has a stronger osteogenic activity than genistein. In addition, while the prenyl group on C-8 of icariin could be the active group that takes part in osteoblastic differentiation and explains its greater potency in osteogenesis, mechanisms of action, and reasons for the relative potency of icariin versus genistein need to be further studied.

[Effect of Osthol on the proliferation and differentiate of osteoblasts in vitro].

OBJECTIVE: To investigate the effects of Osthol on the proliferation and differentiation of osteoblasts of rats (rat calvarial osteoblasts, ROB) cultured in vitro. METHODS: The neonatal SD rat skull was segregated, and enzyme digestion was used to obtain bone cells which were cultured in MEM containing 10% FBS. The medium was changed every three days, and serial subcultivation was performed when cells covered with 90% of the culture dish. The Osthol was added to 96-well plates with final concentration of 1 x 10(-4) mol/L, 1 x 10(-5) mol/L, 1 x l0(-6) mol/L and 1 x10(-7) mol/L, and MTT method was used to evaluate the proliferation. Differentiation analysis: the alkaline phosphatase (ALP) activity was determined at the 3rd, 6th, 9th, 12th and 15th days separately after osteogenic induction culture. The synthesis of type I collagen was observed using immunohistochemical method at the 8th day. The ALP stain was performed at the 12th day. The alizarin red staining was done and calcified nodules was counted at the 14th day. RESULTS: The Osthol with final concentration of 1 x 10(-4) mo/L inhibit the proliferation of ROB. The Osthol with final concentration of 1 x 10(-5) mol/L had no obvious influence on the proliferation of ROB, but it significantly promoted the activity of ALP, enhanced the synthesis of collagen type I and increased the number of calcified nodules. CONCLUSION: The Osthol with final concentration of 1 x 10(-5) mol/L can promote differentiation and maturation of ROB, which may be active ingredients of Chinese drugs for the osteoporosis prophylaxis.

[Comparative study on the osteogenic differentiation of rat bone marrow stromal cells effected by icariin and icariside II].

OBJECTIVE: To investigate the effects of icariin and it's main metabolites-icariside II on the osteogenic differentiation of rat bone marrow stromal cells (rBMSCs). METHODS: rBMSCs were cultured by adherence screening method, icariin and icariside II were supplemented into the culture at 5 x 10(-5) mol/L respectively. The osteogenic differentiation markers including alkaline phosphatase (ALP) activity, CFU-F(ALp), osteocalcin secretion, calcium deposition and mineralized bone modulus were compared among the icariin-supplemented group, icariside II and the control. The gene expressions of bFGF, IGF-1, Osterix and Runx-2 were examined by RT-Real Time PCR. RESULTS: Both icariside II and icariin significantly improved ALP activity, CFU-F(ALP) amount, osteocalcin secretion, calcium deposition and mineralized modulus. Besides, they enhanced the gene expressions of bFGF, IGF-1, Osterix and Runx-2. Icariside II was obviously stronger than icariin at the above activities. CONCLUSION: Icariside II is stronger than icariin at enhancing the osteogenic differentiation of rBMSCs, suggesting that icariin can be administered via oral and it's metabolites are the effective constitutes for antiosteoporosis activity.