Therapeutic Targeting Notch2 Protects Bone Micro-Vasculatures from Methotrexate Chemotherapy-Induced Adverse Effects in Rats

Intensive cancer chemotherapy is well known to cause bone vasculature disfunction and damage, but the mechanism is poorly understood and there is a lack of treatment. Using a rat model of methotrexate (MTX) chemotherapy (five once-daily dosses at 0.75 mg/kg), this study investigated the roles of the Notch2 signalling pathway in MTX chemotherapy-induced bone micro-vasculature impairment. Gene expression, histological and micro-computed tomography (micro-CT) analyses revealed that MTX-induced micro-vasculature dilation and regression is associated with the induction of Notch2 activity in endothelial cells and increased production of inflammatory cytokine tumour necrosis factor alpha (TNFα) from osteoblasts (bone forming cells) and bone marrow cells. Blockade of Notch2 by a neutralising antibody ameliorated MTX adverse effects on bone micro-vasculature, both directly by supressing Notch2 signalling in endothelial cells and indirectly via reducing TNFα production. Furthermore, in vitro studies using rat bone marrow-derived endothelial cell revealed that MTX treatment induces Notch2/Hey1 pathway and negatively affects their ability in migration and tube formation, and Notch2 blockade can partially protect endothelial cell functions from MTX damage.Yaser Peymanfar, Yu-Wen Su, Mohammadhossein Hassanshahi and Cory J. Xia

Roles of microRNAs in osteogenesis or adipogenesis differentiation of bone marrow stromal progenitor cells

Bone marrow stromal cells (BMSCs) are multipotent cells which can differentiate into chondrocytes, osteoblasts, and fat cells. Under pathological stress, reduced bone formation in favour of fat formation in the bone marrow has been observed through a switch in the differentiation of BMSCs. The bone/fat switch causes bone growth defects and disordered bone metabolism in bone marrow, for which the mechanisms remain unclear, and treatments are lacking. Studies suggest that small non-coding RNAs (microRNAs) could participate in regulating BMSC differentiation by disrupting the post-transcription of target genes, leading to bone/fat formation changes. This review presents an emerging concept of microRNA regulation in the bone/fat formation switch in bone marrow, the evidence for which is assembled mainly from in vivo and in vitro human or animal models. Characterization of changes to microRNAs reveals novel networks that mediate signalling and factors in regulating bone/fat switch and homeostasis. Recent advances in our understanding of microRNAs in their control in BMSC differentiation have provided valuable insights into underlying mechanisms and may have significant potential in development of new therapeutics.Ya-Li Zhang, Liang Liu, Yaser Peymanfar, Paul Anderson and Cory J. Xia

Plasmodium sexual stage parasites present distinct targets for malaria transmission-blocking vaccine design

Taylor-Robinson, AW ORCiD: 0000-0001-7342-8348Malaria is an infectious disease that in humans is caused by one of five species of the protozoan parasite Plasmodium and which is transmitted by mosquitoes of the genus Anopheles. Despite much investment over many years to eradicate or control the global incidence of malaria, infection remains a major cause of morbidity and mortality throughout the world, particularly in developing countries in tropical and subtropical regions. A large number of candidate vaccines has been developed against different antigens expressed by separate life cycle stages of Plasmodium. Transmission-blocking vaccines (TBVs) aim to combat the sexual stages of parasite development that occur distinctively inside the mosquito vector. This also has a potentially significant impact on the efficacy of other malaria vaccines which target stage-specific antigens expressed within humans by reducing the spread of parasites in the community, an altruistic approach that leads to a local herd immune response. In 1958 the first successful steps towards producing a TBV used an avian model to raise sexual stage-specific antibodies. In the almost 60 years that have elapsed since this proof of principle demonstration considerable effort has been expended in order to identify parasite antigens the expression of which elicits transmission-blocking activity. This review considers the significance of an anti-malaria TBV strategy, the range of potential targets, and the incremental advances which have been made to produce effective TBVs

Plasmodium sexual stage parasites present distinct targets for malaria transmission-blocking vaccine design

Malaria is an infectious disease that in humans is caused by one of five species of the protozoan parasite Plasmodium and which is transmitted by mosquitoes of the genus Anopheles. Despite much investment over many years to eradicate or control the global incidence of malaria, infection remains a major cause of morbidity and mortality throughout the world, particularly in developing countries in tropical and subtropical regions. A large number of candidate vaccines has been developed against different antigens expressed by separate life cycle stages of Plasmodium. Transmission-blocking vaccines (TBVs) aim to combat the sexual stages of parasite development that occur distinctively inside the mosquito vector. This also has a potentially significant impact on the efficacy of other malaria vaccines which target stage-specific antigens expressed within humans by reducing the spread of parasites in the community, an altruistic approach that leads to a local herd immune response. In 1958 the first successful steps towards producing a TBV used an avian model to raise sexual stage-specific antibodies. In the almost 60 years that have elapsed since this proof of principle demonstration considerable effort has been expended in order to identify parasite antigens the expression of which elicits transmission-blocking activity. This review considers the significance of an anti-malaria TBV strategy, the range of potential targets, and the incremental advances which have been made to produce effective TBVs

Methotrexate treatment suppresses osteoblastic differentiation by inducing Notch2 signaling and blockade of Notch2 rescues osteogenesis by preserving Wnt/β-catenin signaling

Methotrexate (MTX) is a commonly used antimetabolite in cancer treatment. Its intensive use is linked with skeletal adverse effects such as reduced bone formation and bone loss, and yet little information is available on molecular mechanisms underlying MTX‐induced impaired bone formation. This study investigated the effects of MTX treatment at a clinical chemotherapy relevant dose on osteogenic differentiation in MC3T3E1 osteoblastic cells. To investigate the potential mechanisms, the expression of 87 genes regulating osteoblast differentiation and bone homeostasis was screened in MTX‐treated versus untreated cells by polymerase chain reaction (PCR) arrays and results illustrated significant upregulation of Notch2 and Notch target genes at both early and late stages of MC3T3E1 differentiation following MTX treatment. To confirm the roles of Notch2 pathway and its potential action mechanisms, MC3T3E1 cells were treated with MTX with an anti‐Notch2 neutralizing antibody or control IgG and effects were examined on osteogenesis and activation of the Wnt/β‐catenin pathway. Our results demonstrated that induction of Notch2 activity is associated with MTX adverse effects on osteogenic differentiation and blocking Notch2 rescues osteoblast differentiation by preserving activation of the Wnt/β‐catenin pathway.Yaser Peymanfar, Yu, Wen Su, Mohammadhossein Hassanshahi, Cory J. Xia

Roles of apoptotic chondrocyte-derived CXCL12 in the enhanced chondroclast recruitment following methotrexate and/or dexamethasone treatment

Intensive use of methotrexate (MTX) and/or dexamethasone (DEX) for treating childhood malignancies is known to cause chondrocyte apoptosis and growth plate dysfunction leading to bone growth impairments. However, mechanisms remain vague and it is unclear whether MTX and DEX combination treatment could have additive effects in the growth plate defects. In this study, significant cell apoptosis was induced in mature ATDC5 chondrocytes after treatment for 48 h with 10-5  M MTX and/or 10-6  M DEX treatment. PCR array assays with treated cells plus messenger RNA and protein expression confirmation analyses identified chemokine CXCL12 having the most prominent induction in each treatment group. Conditioned medium from treated chondrocytes stimulated migration of RAW264.7 osteoclast precursor cells and formation of osteoclasts, and these stimulating effects were inhibited by the neutralizing antibody for CXCL12. Additionally, while MTX and DEX combination treatment showed some additive effects on apoptosis induction, it did not have additive or counteractive effects on CXCL12 expression and its functions in enhancing osteoclastic recruitment and formation. In young rats treated acutely with MTX, there was increased expression of CXCL12 in the tibial growth plate, and more resorbing chondroclasts were found present at the border between the hypertrophic growth plate and metaphysis bone. Thus, the present study showed an association between induced chondrocyte apoptosis and stimulated osteoclastic migration and formation following MTX and/or DEX treatment, which could be potentially or at least partially linked molecularly by CXCL12 induction. This finding may contribute to an enhanced mechanistic understanding of bone growth impairments following MTX and/or DEX therapy.Yu‐Wen Su, Jian Fan, Chia‐Ming Fan, Yaser Peymanfar, Ya‐Li Zhang, Cory J. Xia

Opioids and matrix metalloproteinases: the influence of morphine on MMP-9 production and cancer progression

Opioids are widely administered to alleviate pain, including chronic pain in advanced cancer patients. Among opioids, morphine is one of the most clinically effective drugs for the palliative management of severe pain. In the last few decades, there has been a debate around the possible influence of opioids such as morphine on tumour growth and metastasis. Whilst several in vitro and in vivo studies suggest the possible modulatory effects of morphine on tumour cells, little is known about the impact of this analgesic drug on other mediators such as matrix metalloproteinases (MMPs) that play a key role in the control of cancer cell invasion and metastasis. MMP-9 has been considered as one of the principal mediators in regulation of not only the initial steps of cancer but during the invasion and spreading of cancer cells to distant organs. Herein, current studies regarding the direct and indirect effects of morphine on regulation of MMP-9 production are discussed. In addition, drawing from previous in vivo and in vitro studies on morphine action in regulating MMP-9 production, the potential roles of several underlying factors are summarised, including nuclear factor kappa-B and intracellular molecules such as nitric oxide.Samira Khabbazi, Mohammadhossein Hassanshahi, Alireza Hassanshahi, Yaser Peymanfar, Yu-Wen Su, Cory J. Xia

Critical limb ischemia: Current and novel therapeutic strategies

Critical limb ischemia (CLI) is the advanced stage of peripheral artery disease spectrum and is defined by limb pain or impending limb loss because of compromised blood flow to the affected extremity. Current conventional therapies for CLI include amputation, bypass surgery, endovascular therapy, and pharmacological approaches. Although these conventional therapeutic strategies still remain as the mainstay of treatments for CLI, novel and promising therapeutic approaches such as proangiogenic gene/protein therapies and stem cell-based therapies have emerged to overcome, at least partially, the limitations and disadvantages of current conventional therapeutic approaches. Such novel CLI treatment options may become even more effective when other complementary approaches such as utilizing proper bioscaffolds are used to increase the survival and engraftment of delivered genes and stem cells. Therefore, herein, we address the benefits and disadvantages of current therapeutic strategies for CLI treatment and summarize the novel and promising therapeutic approaches for CLI treatment. Our analyses also suggest that these novel CLI therapeutic strategies show considerable advantages to be used when current conventional methods have failed for CLI treatment