Potential therapeutic role of spermine via Rac1 in osteoporosis: Insights from zebrafish and mice.

Osteoporosis is a prevalent metabolic bone disease. While drug therapy is essential to prevent bone loss in osteoporotic patients, current treatments are limited by side effects and high costs, necessitating the development of more effective and safer targeted therapies. Utilizing a zebrafish ( Danio rerio) larval model of osteoporosis, we explored the influence of the metabolite spermine on bone homeostasis. Results showed that spermine exhibited dual activity in osteoporotic zebrafish larvae by increasing bone formation and decreasing bone resorption. Spermine not only demonstrated excellent biosafety but also mitigated prednisolone-induced embryonic neurotoxicity and cardiotoxicity. Notably, spermine showcased protective attributes in the nervous systems of both zebrafish embryos and larvae. At the molecular level, Rac1 was identified as playing a pivotal role in mediating the anti-osteoporotic effects of spermine, with P53 potentially acting downstream of Rac1. These findings were confirmed using mouse ( Mus musculus) models, in which spermine not only ameliorated osteoporosis but also promoted bone formation and mineralization under healthy conditions, suggesting strong potential as a bone-strengthening agent. This study underscores the beneficial role of spermine in osteoporotic bone homeostasis and skeletal system development, highlighting pivotal molecular mediators. Given their efficacy and safety, human endogenous metabolites like spermine are promising candidates for new anti-osteoporotic drug development and daily bone-fortifying agents.

Spermine enhances the activity of anti-tuberculosis drugs.

IMPORTANCE: This is the first study that attempted to demonstrate the mechanisms of reactive oxygen species (ROS) generation by spermine (Spm) in Mycobacterium tuberculosis (M.tb). Furthermore, this is the first study to demonstrate that it is able to enhance the activity of currently available and World Health Organization (WHO)-approved tuberculosis (TB) drugs. Spermine can easily be obtained since it is already found in our diet. Moreover, as opposed to conventional antibiotics, it is less toxic to humans since it is found in millimolar concentrations in the body. Finally, with the difficulty of curing TB with conventional antibiotics, this study suggests that less toxic molecules, such as Spm, could in a long-term perspective be incorporated in a TB regimen to boost the treatment.

Synergistic antitumor efficacy of gemcitabine and cisplatin to induce ferroptosis in pancreatic ductal adenocarcinoma via Sp1-SAT1-polyamine metabolism pathway.

PURPOSE: The combination of cisplatin and gemcitabine-based chemotherapy has been recommended as a preferred regimen for pancreatic ductal adenocarcinoma (PDAC) patients with germline-based mutations. However, the underlying mechanism remains poorly elucidated. Therefore, our study aimed to explore the mechanistic basis of the cell-killing activity of gemcitabine plus cisplatin and identify potential therapeutic targets. METHODS: First, we explored the synergistic cytotoxic effects of gemcitabine and cisplatin on PDAC through in vitro and in vivo experiments. Then, we investigated ferroptosis-related biomarkers, to assess the impact of the combination therapy on ferroptosis. Using bioinformatics methods, we identified SAT1 as a potential key mediator of ferroptosis induced by gemcitabine and cisplatin. We tested the polyamine levels in PDAC cells by LC-MS after overexpressed or knocked down SAT1, and explored the role of polyamines in ferroptosis using exogenous supplementation. Finally, we explored the regulatory effect of Sp1 on SAT1 through ChIP-qPCR and dual-luciferase reporter assay. RESULTS: Gemcitabine plus cisplatin enhanced cell death and induced ferroptosis in PDAC. This combination upregulated SAT1 transcription by inhibiting Sp1. SAT1 activation promoted the catabolism of spermine and spermidine, leading to iron accumulation and lipid peroxide generation, ultimately resulting in ferroptosis. CONCLUSIONS: In summary, our findings suggested the gemcitabine and cisplatin combination therapy induced ferroptosis in a GSH-independent manner in PDAC. The combined treatment inhibited Sp1 and upregulated SAT1 transcription, leading to the breakdown of spermine and spermidine. Therefore, targeting SAT1-induced polyamine metabolism may represent a promising therapeutic strategy for PDAC.

Safety, tolerability, pharmacokinetics, and efficacy of kukoamine B in patients with sepsis: A randomized phase IIa trial.

PURPOSE: To evaluate the safety, tolerability, pharmacokinetics, and efficacy of kukoamine B (KB), an alkaloid compound with high affinity for both lipopolysaccharide (LPS) and oligodeoxynucle-otides containing CpG motifs (CpG DNA), in patients with sepsis-induced organ failure. MATERIALS AND METHODS: This was a multicenter, randomized, double-blind, placebo-controlled phase IIa trial. Patients with sepsis-induced organ failure were randomized to receive either KB (0.06, 0.12, or 0.24 mg/kg) or placebo, every 8 h for 7 days. Primary endpoint was safety, and secondary endpoints included pharmacokinetic (PK) parameters, changes in inflammatory mediators' level, and prognostic parameters. RESULTS: Of 44 patients enrolled, adverse events occurred in 28 patients [n = 20, 66.7% (KB pooled); n = 8, 57.1% (placebo)], while treatment emergent adverse events were reported in 14 patients [n = 10, 33.3% (KB pooled); n = 4, 28.6% (placebo)]. Seven patients died at 28-day follow-up [n = 4, 13.3% (KB pooled); n = 3, 21.4% (placebo)], none was related to study drug. PK parameters suggested dose-dependent drug exposure and no drug accumulation. KB did not affect clinical outcomes such as ΔSOFA score, vasopressor-free days or ventilator-free days. CONCLUSIONS: In patients with sepsis-induced organ failure, KB was safe and well tolerated. Further investigation is warranted. TRIAL REGISTRATION: http://ClinicalTrials.gov, NCT03237728.

Calcium-Sensing Receptor Negative Allosteric Modulators Oppose Contraction of Mouse Airways.

Asthma is a heterogeneous chronic airway disease with an unmet need for improved therapeutics in uncontrolled severe disease. The calcium-sensing receptor (CaSR) is a G protein-coupled receptor upregulated in asthma. The CaSR agonist, spermine, is also increased in asthmatic airways and contributes to bronchoconstriction. CaSR negative allosteric modulators (NAMs) oppose chronic airway inflammation, remodeling, and hyperresponsiveness in murine and guinea pig asthma models, but whether CaSR NAMs are effective acute bronchodilators compared with standard of care has not yet been established. Furthermore, the ability of different classes of NAMs to inhibit spermine-induced CaSR signaling or methacholine (MCh)-induced airway contraction has not been quantified. Here, we show CaSR NAMs differentially inhibit spermine-induced intracellular calcium mobilization and inositol monophosphate accumulation in HEK293 cells stably expressing the CaSR. NAMs reverse MCh-mediated airway contraction in mouse precision-cut lung slices with similar maximal relaxation compared with the standard treatment, salbutamol. Of note, the bronchodilator effects of CaSR NAMs are maintained under conditions of ß2-adrenergic receptor desensitization when salbutamol efficacy is abolished. Furthermore, overnight treatment with some, but not all, CaSR NAMs prevents MCh-mediated bronchoconstriction. These findings further support the CaSR as a putative drug target and NAMs as alternative or adjunct bronchodilators in asthma.

Drug-free tumor therapy via spermine-responsive intracellular biomineralization.

Chemotherapy based on molecular drugs remains the most frequently used approach for the therapy of tumors, however their poor specificity, severe side effects and tumor resistance often seriously hinder their applications. It is therefore desirable to develop a new, alternative therapeutic strategy for tumor treatment without traditional chemotherapeutic drugs. Herein, we report a drug-free tumor therapy approach involving spermine (SPM)-responsive intracellular biomineralization in tumor cells. In this work, we designed calcium carbonate (CaCO3) nanoparticles capped with folic acid and supramolecular peptides, which could target tumor cells and rapidly self-aggregate into micron-sized CaCO3 aggregates in SPM-overexpressed tumor cells. Due to the extended intracellular retention, CaCO3 aggregates could induce intracellular biomineralization and Ca2+ overload of tumor cell, leading to mitochondrial damage and cellular apoptosis, resulting in effective inhibition of tumor growth without serious side effects otherwise seen in conventional chemotherapy.

Understanding the Polyamine and mTOR Pathway Interaction in Breast Cancer Cell Growth.

The polyamines putrescine, spermidine and spermine are nutrient-like polycationic molecules involved in metabolic processes and signaling pathways linked to cell growth and cancer. One important pathway is the PI3K/Akt pathway where studies have shown that polyamines mediate downstream growth effects. Downstream of PI3K/Akt is the mTOR signaling pathway, a nutrient-sensing pathway that regulate translation initiation through 4EBP1 and p70S6K phosphorylation and, along with the PI3K/Akt, is frequently dysregulated in breast cancer. In this study, we investigated the effect of intracellular polyamine modulation on mTORC1 downstream protein and general translation state in two breast cancer cell lines, MCF-7 and MDA-MB-231. The effect of mTORC1 pathway inhibition on the growth and intracellular polyamines was also measured. Results showed that polyamine modulation alters 4EBP1 and p70S6K phosphorylation and translation initiation in the breast cancer cells. mTOR siRNA gene knockdown also inhibited cell growth and decreased putrescine and spermidine content. Co-treatment of inhibitors of polyamine biosynthesis and mTORC1 pathway induced greater cytotoxicity and translation inhibition in the breast cancer cells. Taken together, these data suggest that polyamines promote cell growth in part through interaction with mTOR pathway. Similarly intracellular polyamine content appears to be linked to mTOR pathway regulation. Finally, dual inhibition of polyamine and mTOR pathways may provide therapeutic benefits in some breast cancers.

Bovine Serum Amine Oxidase and Polyamine Analogues: Chemical Synthesis and Biological Evaluation Integrated with Molecular Docking and 3-D QSAR Studies.

Natural polyamines (PAs) are key players in cellular homeostasis by regulating cell growth and proliferation. Several observations highlight that PAs are also implicated in pathways regulating cell death. Indeed, the PA accumulation cytotoxic effect, maximized with the use of bovine serum amine oxidase (BSAO) enzyme, represents a valuable strategy against tumor progression. In the present study, along with the design, synthesis, and biological evaluation of a series of new spermine (Spm) analogues (1-23), a mixed structure-based (SB) and ligand-based (LB) protocol was applied. Binding modes of BSAO-PA modeled complexes led to clarify electrostatic and steric features likely affecting the BSAO-PA biochemical kinetics. LB and SB three-dimensional quantitative structure-activity relationship (Py-CoMFA and Py-ComBinE) models were developed by means of the 3d-qsar.com portal, and their analysis represents a strong basis for future design and synthesis of PA BSAO substrates for potential application in oxidative stress-induced chemotherapy.

Recent Advances in Fluorescent Methods for Polyamine Detection and the Polyamine Suppressing Strategy in Tumor Treatment.

The biogenic aliphatic polyamines (spermine, spermidine, and putrescine) are responsible for numerous cell functions, including cell proliferation, the stabilization of nucleic acid conformations, cell division, homeostasis, gene expression, and protein synthesis in living organisms. The change of polyamine concentrations in the urine or blood is usually related to the presence of malignant tumors and is regarded as a biomarker for the early diagnosis of cancer. Therefore, the detection of polyamine levels in physiological fluids can provide valuable information in terms of cancer diagnosis and in monitoring therapeutic effects. In this review, we summarize the recent advances in fluorescent methods for polyamine detection (supramolecular fluorescent sensing systems, fluorescent probes based on the chromophore reaction, fluorescent small molecules, and fluorescent nanoparticles). In addition, tumor polyamine-suppressing strategies (such as polyamine conjugate, polyamine analogs, combinations that target multiple components, spermine-responsive supramolecular chemotherapy, a combination of polyamine consumption and photodynamic therapy, etc.) are highlighted. We hope that this review promotes the development of more efficient polyamine detection methods and provides a comprehensive understanding of polyamine-based tumor suppressor strategies.

Spermine alleviates experimental autoimmune encephalomyelitis via regulating T cell activation and differentiation.

Multiple sclerosis (MS) is a chronic neuroinflammatory disease which causes demyelination, axonal damage and even disability. Th1 and Th17 cells, more precisely, the IFNγ/IL17a double producing CD4+ T cells, have been known to play critical roles in the pathogenesis of MS and EAE, a mouse model of MS. Polyamines not only regulate the immune system, but also are essential for the normal function of the central nervous system (CNS). In this study, we demonstrate that the supplementation of spermine (SPM), a biogenic polyamine, significantly suppresses EAE progression in both preventative and therapeutic ways. Further study suggests that spermine significantly reduces IFNγ+/IL17a-, IFNγ-/IL17a+ and IFNγ+/IL17a+ cells in periphery, and thus reducing the infiltration of these pathogenic cells into the CNS. In vitro, spermine has been shown to suppress the activation and proliferation of CD4+ T cells and also significantly impede the polarization of T effector cells in a dose-dependent manner, accompanied by the inhibition of ERK phosphorylation. Consistently, a number of MEK/ERK inhibitors (including PD0325901, FR180204 and selumetinib) have been found to mimic the effects of spermine in inhibiting CD4+ T cell activation and T effector cell differentiation. Collectively, spermine alleviates EAE progression by inhibiting CD4+ T cells activation and T effector cell differentiation in a MAPK/ERK-dependent manner, suggesting this pathway might be a target to develop effective therapies for MS.

Procognitive activity of nitric oxide inhibitors and donors in animal models.

Nitric oxide is a small gaseous molecule that plays important roles in the majority of biological functions. Impairments of NO-related pathways contribute to the majority of neurological disorders, such as Alzheimer's disease (AD), and mental disorders, such as schizophrenia. Cognitive decline is one of the most serious impairments accompanying both AD and schizophrenia. In the present study, the activities of NO donors, slow (spermine NONOate) or fast (DETANONOate) releasers, and selective inhibitor of neuronal nitric oxide synthase N(ω)-propyl-l-arginine (NPLA) were investigated in pharmacological models of schizophrenia and AD. Cognitive impairments were induced by administration of MK-801 or scopolamine and were measured in novel object recognition (NOR) and Y-maze tests. The compounds were investigated at doses of 0.05-0.5 mg/kg. The dose-dependent effectiveness of all the compounds was observed in the NOR test, while only the highest doses of spermine NONOate and NPLA were active in the Y-maze test. DETANONOate was not active in the Y-maze test. The impact of the investigated compounds on motor coordination was tested at doses of 0.5 and 1 mg/kg. Only NPLA at a dose of 1 mg/kg slightly disturbed motor coordination in animals.

Development of a Redox-Sensitive Spermine Prodrug for the Potential Treatment of Snyder Robinson Syndrome.

Snyder Robinson Syndrome (SRS) is a rare disease associated with a defective spermine synthase gene and low intracellular spermine levels. In this study, a spermine replacement therapy was developed using a spermine prodrug that enters cells via the polyamine transport system. The prodrug was comprised of three components: a redox-sensitive quinone "trigger", a "trimethyl lock (TML)" aryl "release mechanism", and spermine. The presence of spermine in the design facilitated uptake by the polyamine transport system. The quinone-TML motifs provided a redox-sensitive agent, which upon intracellular reduction generated a hydroquinone, which underwent intramolecular cyclization to release free spermine and a lactone byproduct. Rewardingly, most SRS fibroblasts treated with the prodrug revealed a significant increase in intracellular spermine. Administering the spermine prodrug through feeding in a Drosophila model of SRS showed significant beneficial effects. In summary, a spermine prodrug is developed and provides a lead compound for future spermine replacement therapy experiments.

Tyrosine phosphatase PTP1B impairs presynaptic NMDA receptor-mediated plasticity in a mouse model of Alzheimer's disease.

Mutations in the beta-amyloid protein (APP) cause familial Alzheimer's disease. In hAPP-J20 mice expressing mutant APP, pharmacological inhibition or genetic ablation of the tyrosine phosphatase PTP1B prevents CA3 hippocampus neuron loss and cognitive decline. However, how targeting PTP1B affects the cellular mechanisms underlying these cognitive deficits remains unknown. Changes in synaptic strength at the hippocampus can affect information processing for learning and memory. While prior studies have focused on post-synaptic mechanisms to account for synaptic deficits in Alzheimer's disease models, presynaptic mechanisms may also be affected. Here, using whole cell patch-clamp recording, coefficient of variation (CV) analysis suggested a profound presynaptic deficit in long-term potentiation (LTP) of CA3:CA1 synapses in hAPP-J20 mice. While the membrane-impermeable ionotropic NMDA receptor (NMDAR) blocker norketamine in the post-synaptic recording electrode had no effect on LTP, additional bath application of the ionotropic NMDAR blockers MK801 could replicate the deficit in LTP in wild type mice. In contrast to LTP, the paired-pulse ratio and short-term facilitation (STF) were aberrantly increased in hAPP-J20 mice. These synaptic deficits in hAPP-J20 mice were associated with reduced phosphorylation of NMDAR GluN2B and the synaptic vesicle recycling protein NSF (N-ethylmaleimide sensitive factor). Phosphorylation of both proteins, together with synaptic plasticity and cognitive function, were restored by PTP1B ablation or inhibition by the PTP1B-selective inhibitor Trodusquemine. Taken together, our results indicate that PTP1B impairs presynaptic NMDAR-mediated synaptic plasticity required for spatial learning in a mouse model of Alzheimer's disease. Since Trodusquemine has undergone phase 1/2 clinical trials to treat obesity, it could be repurposed to treat Alzheimer's disease.

Ketamine's schizophrenia-like effects are prevented by targeting PTP1B.

Subanesthetic doses of ketamine induce schizophrenia-like behaviors in mice including hyperlocomotion and deficits in working memory and sensorimotor gating. Here, we examined the effect of in vivo ketamine administration on neuronal properties and endocannabinoid (eCB)-dependent modulation of synaptic transmission onto layer 2/3 pyramidal neurons in brain slices of the prefrontal cortex, a region tied to the schizophrenia-like behavioral phenotypes of ketamine. Since deficits in working memory and sensorimotor gating are tied to activation of the tyrosine phosphatase PTP1B in glutamatergic neurons, we asked whether PTP1B contributes to these effects of ketamine. Ketamine increased membrane resistance and excitability of pyramidal neurons. Systemic pharmacological inhibition of PTP1B by Trodusquemine restored these neuronal properties and prevented each of the three main ketamine-induced behavior deficits. Ketamine also reduced mobilization of eCB by pyramidal neurons, while unexpectedly reducing their inhibitory inputs, and these effects of ketamine were blocked or occluded by PTP1B ablation in glutamatergic neurons. While ablation of PTP1B in glutamatergic neurons prevented ketamine-induced deficits in memory and sensorimotor gating, it failed to prevent hyperlocomotion (a psychosis-like phenotype). Taken together, these results suggest that PTP1B in glutamatergic neurons mediates ketamine-induced deficits in eCB mobilization, memory and sensorimotor gating whereas PTP1B in other cell types contributes to hyperlocomotion. Our study suggests that the PTP1B inhibitor Trodusquemine may represent a new class of fast-acting antipsychotic drugs to treat schizophrenia-like symptoms.

[Spermine attenuates high glucose-induced myocardial fibrosis by regulating the cell cycle].

Objective: To investigate the protective effect of spermine (Sp) on diabetic cardiomyopathy (DCM) and high glucose-induced cardiac fibroblasts (CFs), and to explore its mechanism.Methods: ①Animal experiments: 24 male Wistar rats were randomly divided into control group, type 1 diabetes group (TID) and spermine group (TID+Sp, each group n=8). TID rats were induced by streptozocin (STZ, 60 mg/kg), and TID+Sp rat were pretreated with spermine (Sp, 5 mg/(kg·d)) for 2 weeks before STZ injection. After 12 weeks of modeling, blood glucose, insulin levels, ejection fraction (EF) and shortening fraction (FS) were measured, and Masson staining and Sirius red staining were performed in the rat cardiac tissues. ②Cell experiments: primary CFs were extracted from newborn (1-3 d) Wistar rat hearts, and were randomly divided into control group, high-glucose group (HG) and HG+Sp group (n=6 per group). HG group was treated with 40 mmol/L glucose, and the HG+Sp group was pretreated with 5 µmol/L Sp for 30 min before HG treatment. The cell viability of CFs was detected by CCK8, the content of collagen in culture medium was analyzed by ELISA, and protein expressions of cell cycle related proteins (PCNA, CyclinD1 and P27) were detected by Western blot. Results: Compared with control group, the blood glucose and collagen content were increased, and the insulin level and heart function were decreased in the T1D group. Meanwhile, HG induced an increasing of the cell viability, the collagen content in the medium and the expressions of PCNA and CyclinD1, while the expression of P27 was down-regulated. Spermine could reduce the above changes, manifested as improving the cardiac function, regulating the expression of cyclin and reducing the level of myocardial fibrosis. Conclusion: Spermine can alleviate myocardial fibrosis in diabetic cardiomyopathy, which mechanism is related to the regulation of cell cycle.

[Effect of exogenous spermine pretreatment on alleviating renal fibrosis in diabetic nephropathy mice and its related mechanism].

Objective: To observe the protective effects of exogenous spermine on renal fibrosis induced by diabetic nephropathy (DN) and to explore its mechanism.Methods: Twenty-four male C57 mice were randomly divided into control group, type 1 diabetes group (TID) and spermine pretreatment group (TID+Sp, n=8 in each group). TID mice were induced by STZ (60 mg/kg), and TID+Sp mice were pretreated with spermine (5 mg/(kg·d)) for 2 weeks before STZ injection. The mice were killed at the 12th week. The renal function was determined by serum creatinine and urea nitrogen. HE, PAS and Masson staining were used to evaluate renal tissue injury and fibrosis. The expressions of matrix metalloproteinase (MMP-2, MMP-9) and collagen IV (Coll-IV) in the kidney of mice were detected by Western blot. Results: Compared with the control group, the blood glucose (5.67±0.22 vs 28.40±0.57 mmol/L), creatinine (14.33±1.22 vs 30.67±4.73 µmol/L) and urea nitrogen (6.93±4.94 vs 22.00±1.04 mmol/L) in the T1D group were increased significantly (P＜0.05), the glomerular basement membrane was thickened, the collagen was significantly increased, the expressions of MMP-2, MMP-9 and Coll-IV protein were increased (0.57±0.07 vs 1.06±0.20, 47.00±0.04 vs 1.29±0.09 and 0.42±0.16 vs 0.95±0.18,P＜0.05). Exogenous spermine significantly alleviates the above-mentioned changes. Conclusion: Exogenous spermine pretreatment could significantly alleviate renal fibrosis in diabetic mice by regulating the balance between MMPs and collagen.

Exogenous spermine attenuates myocardial fibrosis in diabetic cardiomyopathy by inhibiting endoplasmic reticulum stress and the canonical Wnt signaling pathway.

Myocardial fibrosis is one of the main pathological manifestations of diabetic cardiomyopathy (DCM). Spermine (SPM), a product of polyamine metabolism, plays an important role in many cardiac diseases including hypertrophy, ischemia, and infarction, but its role in diabetic myocardial fibrosis has not been clarified. This study aimed to investigate the role of polyamine metabolism, specifically SPM, in diabetic myocardial fibrosis and to explore the related mechanisms. We used intraperitoneal injection of streptozotocin (STZ, 60 mg/kg) in Wistar rats and high glucose (HG, 40 mM) stimulated cardiac fibroblasts (CFs) to established a type 1 diabetes (T1D) model in vivo and in vitro, which were pretreated with exogenous SPM (5 mg/kg per day and 5 µM). The results showed that hyperglycemia induced the expression of the key polyamine synthesis enzyme ornithine decarboxylase (ODC) decreased and the key catabolic enzyme spermidine/spermine N1 -acetyltransferase (SSAT) increased compared with those in the control group. The body weight, blood insulin level, and cardiac ejection function were decreased, while blood glucose, heart weight, the ratio of heart weight to body weight, myocardial interstitial collagen deposition, and endoplasmic reticulum stress (ERS)-related protein (glucose-regulated protein-78, glucose-regulated protein-94, activating transcription factor-4, and C/EBP homology protein) expression in the T1D group were all significantly increased. HG also caused an increased expression of Wnt3, ß-catenin (in cytoplasm and nucleus), while Axin2 and phosphorylated ß-catenin decreased. Exogenous SPM improved the above changes caused by polyamine metabolic disorders. In conclusion, polyamine metabolism disorder occurs in the myocardial tissue of diabetic rats, causing myocardial fibrosis and ERS. Exogenous SPM plays a myocardial protective role via inhibiting of ERS and the canonical Wnt/ß-catenin signaling pathway.

Anti-Osteoporotic Effects of Kukoamine B Isolated from Lycii Radicis Cortex Extract on Osteoblast and Osteoclast Cells and Ovariectomized Osteoporosis Model Mice.

Osteoporosis is an abnormal bone remodeling condition characterized by decreased bone density, which leads to high risks of fracture. Previous study has demonstrated that Lycii Radicis Cortex (LRC) extract inhibits bone loss in ovariectomized (OVX) mice by enhancing osteoblast differentiation. A bioactive compound, kukoamine B (KB), was identified from fractionation of an LRC extract as a candidate component responsible for an anti-osteoporotic effect. This study investigated the anti-osteoporotic effects of KB using in vitro and in vivo osteoporosis models. KB treatment significantly increased the osteoblastic differentiation and mineralized nodule formation of osteoblastic MC3T3-E1 cells, while it significantly decreased the osteoclast differentiation of primary-cultured monocytes derived from mouse bone marrow. The effects of KB on osteoblastic and osteoclastic differentiations under more physiological conditions were also examined. In the co-culture of MC3T3-E1 cells and monocytes, KB promoted osteoblast differentiation but did not affect osteoclast differentiation. In vivo experiments revealed that KB significantly inhibited OVX-induced bone mineral density loss and restored the impaired bone structural properties in osteoporosis model mice. These results suggest that KB may be a potential therapeutic candidate for the treatment of osteoporosis.

Trodusquemine enhances Aß42 aggregation but suppresses its toxicity by displacing oligomers from cell membranes.

Transient oligomeric species formed during the aggregation process of the 42-residue form of the amyloid-ß peptide (Aß42) are key pathogenic agents in Alzheimer's disease (AD). To investigate the relationship between Aß42 aggregation and its cytotoxicity and the influence of a potential drug on both phenomena, we have studied the effects of trodusquemine. This aminosterol enhances the rate of aggregation by promoting monomer-dependent secondary nucleation, but significantly reduces the toxicity of the resulting oligomers to neuroblastoma cells by inhibiting their binding to the cellular membranes. When administered to a C. elegans model of AD, we again observe an increase in aggregate formation alongside the suppression of Aß42-induced toxicity. In addition to oligomer displacement, the reduced toxicity could also point towards an increased rate of conversion of oligomers to less toxic fibrils. The ability of a small molecule to reduce the toxicity of oligomeric species represents a potential therapeutic strategy against AD.

[Exogenous spermine alleviates myocardial injury induced by hyperglycemia by inhibiting golgi stress].

OBJECTIVE: To investigate whether Golgi stress (GAS) is involved in diabetic cardiomyopathy (DCM) and whether myocardial protection of exogenous spermine is associated with regulation of GAS. METHODS: Sixty Wistar rats were randomly divided into normal control group (Control), diabetic group (T1D, STZ 60 mg/kg intraperitoneal injection) and spermine group (T1D+Sp, spermine 5 mg/(kg·d) intraperitoneal injection) for 12 weeks. H9C2 rat cardiomyocytes were randomly divided into control group (Control, 10% FBS-DMEM culture), high glucose group (HG, 10% FBS-DMEM+40 mmol/L glucose) and spermine group (HG+Sp, 10% FBS-DMEM+40 mmol/L glucose+5 µmol/L spermine). Rat serum creatine kinase isoenzyme (CK-MB) and cardiac troponin T (cTnT) were detected by ELISA; Golgi protein GOLPH3, GM130 and Cleaved Caspase3 protein expressions were analyzed using Western blot; immunofluorescence was used to detect GOLPH3 cell localization. RESULTS: In the animal model, compared with the normal group, myocardial ultrastructural damage was obvious,the blood glucose, the serum myocardial enzymes CK-MB and cTnT, the expressions of GOLPH3 and cleaved caspase3 were increased or up-regulated significantly,meanwhile, the body weight,the ejection fraction (EF) and the expression of GM130 were decreased or down-regulated markedly in the diabetic group. In the cell model, similar results were obtained. Immunofluorescence showed stress fragmentation of Golgi apparatus. Exogenous spermine treatment could significantly alleviate the above mentioned damages. CONCLUSION: Golgi stress occurs in diabetic cardiomyopathy (DCM), and myocardial protection of exogenous spermine is associated with a reduction in Golgi stress (GAS).