Mast Cells Drive Systemic Inflammation and Compromised Bone Repair After Trauma.

There is evidence that mast cells contribute to inflammation induced by hemorrhagic shock, severe tissue injury or sepsis. Mast cells are highly responsive to alarm signals generated after trauma, and release many inflammatory mediators including interleukin-6, a key mediator of posttraumatic inflammation. An overwhelming posttraumatic inflammation causes compromised bone healing; however, the underlying cellular and molecular mechanisms are poorly understood. Recently, we found that mast cells trigger local and systemic inflammation after isolated fracture leading to uneventful bone repair. Here, we investigated whether mast cells critically contribute to trauma-induced compromised bone healing. Male Mcpt5-Cre+ R-DTA mice, which lack connective tissue type mast cells, and their mast cell-competent Cre- littermates underwent a femur fracture with/without thoracic trauma. Posttraumatic systemic and local inflammation and bone repair were assessed 3 h and 21 d post injury. Both, the systemic and pulmonary inflammation was significantly increased in mast cell-competent mice upon combined trauma compared to isolated fracture. In mast cell-deficient mice, the increase of inflammatory mediators in the circulation induced by the severe trauma was abolished. In the bronchoalveolar lavage fluid, the trauma-induced increase of inflammatory cytokines was not reduced, but the neutrophil invasion into the lungs was significantly diminished in the absence of mast cells. Locally in the fracture hematoma, mast cell-competent mice displayed reduced inflammatory mediator concentrations after combined trauma compared to isolated fracture, which was abolished in mast cell-deficient mice. Notably, while combined trauma resulted in compromised bone repair in mast cell-competent mice, indicated by significantly reduced bone and increased cartilage fracture callus contents, this was abolished in Mcpt5-Cre+ R-DTA mice. Therefore, mast cells contribute to trauma-induced compromised bone repair and could be a potential target for new treatment options to improve fracture healing in multiply injured patients.

Laboratory assessment of multiple myeloma.

Laboratory testing plays an essential role in the diagnosis and management of patients with multiple myeloma. A variety of chemistry and molecular assays are routinely used to monitor patient progress, response to treatment and relapse. Here, we have reviewed current literature and core guidelines on the details of laboratory testing in myeloma-related investigations. This includes the use and value of protein electrophoresis, serum free light chain and cytogenetic testing. Furthermore, we discuss other traditional chemistry assays essential to myeloma investigation, and potential interferences that may arise due to the disease nature of myeloma, that is, the presence of a monoclonal immunoglobulin. Finally, we discuss the importance of communication in protein electrophoresis results, where laboratorians are required to relate clinically relevant myeloma-relevant information to the ordering physician on the background of a complex pattern of serum or urine proteins. Laboratory testing in myeloma-related investigation relies on several traditional chemistry assays. However, we anticipate new tests and technologies to become available in the future with improved analytical sensitivity, as well as improved clinical sensitivity in identifying patients who are at high risk of progression to multiple myeloma.

Phosphokinome Analysis of Barth Syndrome Lymphoblasts Identify Novel Targets in the Pathophysiology of the Disease.

Barth Syndrome (BTHS) is a rare X-linked genetic disease in which the specific biochemical deficit is a reduction in the mitochondrial phospholipid cardiolipin (CL) as a result of a mutation in the CL transacylase tafazzin. We compared the phosphokinome profile in Epstein-Barr-virus-transformed lymphoblasts prepared from a BTHS patient with that of an age-matched control individual. As expected, mass spectrometry analysis revealed a significant (>90%) reduction in CL in BTHS lymphoblasts compared to controls. In addition, increased oxidized phosphatidylcholine (oxPC) and phosphatidylethanolamine (PE) levels were observed in BTHS lymphoblasts compared to control. Given the broad shifts in metabolism associated with BTHS, we hypothesized that marked differences in posttranslational modifications such as phosphorylation would be present in the lymphoblast cells of a BTHS patient. Phosphokinome analysis revealed striking differences in the phosphorylation levels of phosphoproteins in BTHS lymphoblasts compared to control cells. Some phosphorylated proteins, for example, adenosine monophosphate kinase, have been previously validated as bonafide modified phosphorylation targets observed in tafazzin deficiency or under conditions of reduced cellular CL. Thus, we report multiple novel phosphokinome targets in BTHS lymphoblasts and hypothesize that alteration in the phosphokinome profile may provide insight into the pathophysiology of BTHS and potential therapeutic targets.

Candidate recommendations for protein electrophoresis reporting from the Canadian Society of Clinical Chemists Monoclonal Gammopathy Working Group.

Protein electrophoresis is commonly used as an aid in the diagnosis of monoclonal gammopathies and is performed in many laboratories in Canada and throughout the world. However, unlike many other diagnostic tests, there is limited guidance for standardization and neither guidance nor specific recommendations for clinical reporting of serum (SPE) or urine (UPE) protein electrophoresis and immunotyping available in the literature. Therefore, a Canadian effort was undertaken to recommend standards that cover all aspects of clinical reporting with an ultimate goal towards reporting standardization. The Canadian Society of Clinical Chemists (CSCC) Monoclonal Gammopathy Interest Group (MGIG), which is composed of CSCC members with an interest in protein electrophoresis, has formed a Monoclonal Gammopathy Working Group (MGWG) to take initial steps towards standardization of SPE, UPE and immunotyping. Candidate standardization recommendations were developed, discussed and voted upon by the MGWG. Candidate recommendations that achieved 90% agreement are presented as consensus recommendations. Recommendations that did not achieve 90% consensus remain candidate recommendations and are presented with accompanying MGWG discussion. Eleven consensus recommendations along with candidate recommendations for nomenclature, protein fraction reporting, test utilization, interference handling and interpretive reporting options are presented.

Glucose Uptake and Triacylglycerol Synthesis Are Increased in Barth Syndrome Lymphoblasts.

Barth syndrome (BTHS) is an X-linked genetic disease resulting in loss of cardiolipin (Ptd2Gro). Patients may be predisposed to hypoglycemia and exhibit increases in whole-body glucose disposal rates and a higher fat mass percentage. We examined the reasons for this in BTHS lymphoblasts. BTHS lymphoblasts exhibited a 60% increase (p < 0.004) in 2-[1,2-3H(N)]deoxy-D-glucose uptake, a 40% increase (p < 0.01) in glucose transporter-3 protein expression, an increase in phosphorylated-adenosine monophosphate kinase (AMPK) and a 58% increase (p < 0.001) in the phosphorylated-AMPK/AMPK ratio compared to controls. In addition, BTHS lymphoblasts exhibited a 90% (p < 0.001) increase in D-[U-14C]glucose incorporated into 1,2,3-triacyl-sn-glycerol (TAG) and a 29% increase (p < 0.025) in 1,2-diacyl-sn-glycerol acyltransferase-2 activity compared to controls. Thus, BTHS lymphoblasts exhibit increased glucose transport and increased glucose utilization for TAG synthesis. These results may, in part, explain why BTHS patients exhibit an increase in whole-body glucose disposal rates, may be predisposed to hypoglycemia and exhibit a higher fat mass percentage.

Matrix-Immobilized BMP-2 on Microcontact Printed Fibronectin as an in vitro Tool to Study BMP-Mediated Signaling and Cell Migration.

During development, growth factors (GFs) such as bone morphogenetic proteins (BMPs) exert important functions in several tissues by regulating signaling for cell differentiation and migration. In vivo, the extracellular matrix (ECM) not only provides support for adherent cells, but also acts as reservoir of GFs. Several constituents of the ECM provide adhesive cues, which serve as binding sites for cell trans-membrane receptors, such as integrins. In conveying adhesion-mediated signaling to the intracellular compartment, integrins do not function alone but rather crosstalk and cooperate with other receptors, such as GF receptors. Here, we present a strategy for the immobilization of BMP-2 onto cellular fibronectin (cFN), a key protein of the ECM, to investigate GF-mediated signaling and migration. Following biotinylation, BMP-2 was linked to biotinylated cFN using NeutrAvidin as cross-linker. Characterization with quartz crystal microbalance with dissipation monitoring and enzyme-linked immunosorbent assay confirmed the efficient immobilization of BMP-2 on cFN over a period of 24 h. To validate the bioactivity of matrix-immobilized BMP-2 (iBMP-2), we investigated short- and long-term responses of C2C12 myoblasts, which are an established in vitro model for BMP-2 signaling, in comparison to soluble BMP-2 (sBMP-2) or in absence of GFs. Similarly to sBMP-2, iBMP-2 triggered Smad 1/5 phosphorylation and translocation of the complex to the nucleus, corresponding to the activation of BMP-mediated Smad-dependent pathway. Additionally, successful suppression of myotube formation was observed after 6 days in sBMP-2 and iBMP-2. We next implemented this approach in the fabrication of cFN micropatterned stripes by soft lithography. These stripes allowed cell-surface interaction only on the patterned cFN, since the surface in between was passivated, thus serving as platform for studies on directed cell migration. During a 10-h observation time, the migratory behavior, especially the cells' net displacement, was increased in presence of BMP-2. As such, this versatile tool retains the bioactivity of GFs and allows the presentation of ECM adhesive cues.

Mifepristone treatment results in differential regulation of glycerolipid biosynthesis in baby hamster kidney cells expressing a mifepristone-inducible ABCA1.

ATP binding cassette A1 (ABCA1) transports cholesterol, phospholipids and lipophilic molecules to and across cellular membranes. We examined if ABCA1 expression altered cellular de novo glycerolipid biosynthesis in growing Baby hamster kidney (BHK) cells. Mock BHK cells or cells expressing a mifepristone-inducible ABCA1 (ABCA1) were incubated plus or minus mifepristone and then with [(3)H]serine or [(3)H]inositol or [(3)H]ethanolamine or [methyl-(3)H]choline or [(3)H]glycerol or [(14)C]oleate and radioactivity incorporated into glycerolipids determined. Mifepristone did not affect [1,3-(3)H]glycerol or [(14)C]oleate or [(3)H]ethanolamine or [methyl-(3)H]choline uptake in BHK cells. In contrast, [(3)H]glycerol and [(14)C]oleate incorporated into phosphatidylserine (PtdSer) were elevated 2.4-fold (p < 0.05) and 54% (p < 0.05), respectively, upon ABCA1 induction confirming increased PtdSer biosynthesis from these precursors. However, mifepristone inhibited [(3)H]serine uptake and incorporation into PtdSer indicating that PtdSer synthesis from serine in BHK cells is dependent on serine uptake. Mifepristone stimulated [(3)H]inositol uptake in mock and ABCA1 cells but not its incorporation into phosphatidylinositol indicating that its synthesis from inositol is independent of inositol uptake in BHK cells. [(3)H]glycerol and [(14)C]oleate incorporated into triacylglycerol were reduced and into diacylglycerol elevated only in mifepristone-induced ABCA1 expressing cells due to a decrease in diacylglycerol acyltransferase-1 (DGAT-1) activity. The presence of trichostatin A, a class I and II histone deacetylase inhibitor, reversed the ABCA1-mediated reduction in DGAT-1 activity but did not affect DGAT-1 mRNA expression. Thus, mifepristone has diverse effects on de novo glycerolipid synthesis. We suggest that caution should be exercised when using mifepristone-inducible systems for studies of glycerolipid metabolism in cells expressing glucocorticoid responsive receptors.

The mevalonate cascade as a target to suppress extracellular matrix synthesis by human airway smooth muscle.

Smooth muscle cells promote fibroproliferative airway remodeling in asthma, and transforming growth factor ß1 (TGFß1) is a key inductive signal. Statins are widely used to treat hyperlipidemia. Growing evidence indicates they also exert a positive impact on lung health, but the underlying mechanisms are unclear. We assessed the effects of 3-hydroxy-3-methlyglutaryl-coenzyme A (HMG-CoA) reductase inhibition with simvastatin on the fibrotic function of primary cultured human airway smooth muscle cells. Simvastatin blocked de novo cholesterol synthesis, but total myocyte cholesterol content was unaffected. Simvastatin also abrogated TGFß1-induced collagen I and fibronectin expression, and prevented collagen I secretion. The depletion of mevalonate cascade intermediates downstream from HMG-CoA underpinned the effects of simvastatin, because co-incubation with mevalonate, geranylgeranylpyrophosphate, or farnesylpyrophosphate prevented the inhibition of matrix protein expression. We also showed that human airway myocytes express both geranylgeranyl transferase 1 (GGT1) and farnesyltransferase (FT), and the inhibition of GGT1 (GGTI inhibitor-286, 10 µM), but not FT (FTI inhibitor-277, 10 µM), mirrored the suppressive effects of simvastatin on collagen I and fibronectin expression and collagen I secretion. Moreover, simvastatin and GGTI-286 both prevented TGFß1-induced membrane association of RhoA, a downstream target of GGT1. Our findings suggest that simvastatin and GGTI-286 inhibit synthesis and secretion of extracellular matrix proteins by human airway smooth muscle cells by suppressing GGT1-mediated posttranslational modification of signaling molecules such as RhoA. These findings reveal mechanisms related to evidence for the positive impact of statins on pulmonary health.

Reduction in cholesterol synthesis in response to serum starvation in lymphoblasts of a patient with Barth syndrome.

Barth syndrome is a rare X-linked disease in which mild hypocholesterolemia is observed in some patients. We investigated cholesterol biosynthesis in lymphoblasts from a normal and age-matched Barth syndrome patient. Control and Barth syndrome (DeltaTAZ1) lymphoblasts were incubated in the presence or absence of serum to induce cholesterol synthesis and hydroxymethylglutaryl-coenzyme A reductase activity and expression, and cholesterol biosynthesis from radioactive precursors was determined. Cholesterol biosynthesis from [2-14C]pyruvate was stimulated 2-fold in control cells, but was unchanged in DeltaTAZ1 lymphoblasts, and from [1-14C]acetate was stimulated 77% in control but only 26% in DeltaTAZ1 lymphoblasts upon serum removal, indicating a lower ability of DeltaTAZ1 cells to upregulate cholesterol biosynthesis. The reason was an inability to increase hydroxymethylglutaryl-coenzyme A reductase activity, which was already near maximum in DeltaTAZ1 lymphoblasts, in response to serum removal, compared with control cells. The reduced ability to increase hydroxymethylglutaryl-coenzyme A reductase enzyme activity in DeltaTAZ1 lymphoblasts was due to a decrease in hydroxymethylglutaryl-coenzyme A reductase messenger RNA. Although total cholesterol levels are similar under standard culture conditions, DeltaTAZ1 lymphoblasts have a diminished capacity to respond to increased demand for cholesterol biosynthesis because of an already elevated level of synthesis under standard culture conditions.

Statin-triggered cell death in primary human lung mesenchymal cells involves p53-PUMA and release of Smac and Omi but not cytochrome c.

Statins inhibit 3-hydroxy-3-methyl-glutarylcoenzyme CoA (HMG-CoA) reductase, the proximal enzyme for cholesterol biosynthesis. They exhibit pleiotropic effects and are linked to health benefits for diseases including cancer and lung disease. Understanding their mechanism of action could point to new therapies, thus we investigated the response of primary cultured human airway mesenchymal cells, which play an effector role in asthma and chronic obstructive lung disease (COPD), to simvastatin exposure. Simvastatin induced apoptosis involving caspase-9, -3 and -7, but not caspase-8 in airway smooth muscle cells and fibroblasts. HMG-CoA inhibition did not alter cellular cholesterol content but did abrogate de novo cholesterol synthesis. Pro-apoptotic effects were prevented by exogenous mevalonate, geranylgeranyl pyrophosphate and farnesyl pyrophosphate, downstream products of HMG-CoA. Simvastatin increased expression of Bax, oligomerization of Bax and Bak, and expression of BH3-only p53-dependent genes, PUMA and NOXA. Inhibition of p53 and silencing of p53 unregulated modulator of apoptosis (PUMA) expression partly counteracted simvastatin-induced cell death, suggesting a role for p53-independent mechanisms. Simvastatin did not induce mitochondrial release of cytochrome c, but did promote release of inhibitor of apoptosis (IAP) proteins, Smac and Omi. Simvastatin also inhibited mitochondrial fission with the loss of mitochondrial Drp1, an essential component of mitochondrial fission machinery. Thus, simvastatin activates novel apoptosis pathways in lung mesenchymal cells involving p53, IAP inhibitor release, and disruption of mitochondrial fission.

Cardiolipin synthesis is required to support human cholesterol biosynthesis from palmitate upon serum removal in Hela cells.

We examined whether cardiolipin (CL) synthesis was required to support cholesterol (CH) production from palmitate in Hela cells. Knockdown of human cardiolipin synthase-1 (hCLS1) in Hela cells has been shown to reduce CL synthesis. Therefore Hela cells stably expressing shRNA for hCLS1 and mock control cells were incubated for 16 h with [14C(U)]palmitate bound to albumin (1:1 molar ratio) in the absence or presence of serum. Knockdown of hCLS1 in Hela cells resulted in a reduction in [14C(U)]palmitate incorporation into CL and CH. This reduction in [14C(U)]palmitate incorporation into CH was most pronounced during incubation under serum-free conditions. The reduction in [14C(U)]palmitate incorporation into CH was not due to alterations in total uptake of [14C(U)]palmitate into cells or altered palmitate metabolism, since [14C(U)]palmitate incorporation into phosphatidylcholine, the major [14C(U)]palmitate-containing lipid, and its immediate precursor, 1,2-diacyl-sn-glycerol, were unaffected by hCLS1 knockdown. In addition, knockdown of hCLS1 did not affect CH pool size, indicating that CH catabolism was unaltered. Hydroxymethylglutaryl coenzyme A reductase enzyme activity and its mRNA expression were reduced by knockdown of hCLS1 and this was most pronounced in Hela cells cultured under serum-free conditions. These data indicate that CL synthesis is required to support human de novo CH biosynthesis under conditions of increased demand for CH.

Mechanism of the elevation in cardiolipin during HeLa cell entry into the S-phase of the human cell cycle.

CL (cardiolipin) is a key phospholipid involved in ATP generation. Since progression through the cell cycle requires ATP we examined regulation of CL synthesis during S-phase in human cells and investigated whether CL or CL synthesis was required to support nucleotide synthesis in S-phase. HeLa cells were made quiescent by serum depletion for 24 h. Serum addition resulted in substantial stimulation of [methyl-(3)H]thymidine incorporation into cells compared with serum-starved cells by 8 h, confirming entry into the S-phase. CL mass was unaltered at 8 h, but increased 2-fold by 16 h post-serum addition compared with serum-starved cells. The reason for the increase in CL mass upon entry into S-phase was an increase in activity and expression of CL de novo biosynthetic and remodelling enzymes and this paralleled the increase in mitochondrial mass. CL de novo biosynthesis from D-[U-(14)C]glucose was elevated, and from [1,3-(3)H]glycerol reduced, upon serum addition to quiescent cells compared with controls and this was a result of differences in the selection of precursor pools at the level of uptake. Triascin C treatment inhibited CL synthesis from [1-(14)C]oleate but did not affect [methyl-(3)H]thymidine incorporation into HeLa cells upon serum addition to serum-starved cells. Barth Syndrome lymphoblasts, which exhibit reduced CL, showed similar [methyl-(3)H]thymidine incorporation into cells upon serum addition to serum-starved cells compared with cells from normal aged-matched controls. The results indicate that CL de novo biosynthesis is up-regulated via elevated activity and expression of CL biosynthetic genes and this accounted for the doubling of CL seen during S-phase; however, normal de novo CL biosynthesis or CL itself is not essential to support nucleotide synthesis during entry into S-phase of the human cell cycle.

Cardiolipin metabolism and Barth Syndrome.

Many advances have occurred in the field of Barth Syndrome biology in the 26 years since it was first described as an X-linked cardiomyopathy. Barth Syndrome is the first human disease recognized in which the primary causative factor is an alteration in cardiolipin remodeling. Cardiolipin is required for the optimal function of many proteins within the mitochondria, particularly in the respiratory chain and is involved in the mitochondrial-mediated apoptotic process. The appropriate content of cardiolipin appears to be critical for these functions. Cardiolipin is synthesized de novo in mitochondria and is rapidly remodeled to produce CL enriched in linoleic acid. The Barth Syndrome gene TAZ has been identified and expression of the gene yields proteins known as tafazzins. Mutations in TAZ result in a decrease in tetra-linoleoyl species of cardiolipin and an accumulation of monolysocardiolipin within cells from Barth Syndrome patients. Although the protein product of the TAZ gene shows sequence homology to the glycerolipid acyltransferase family of enzymes, its precise biochemical function remains to be elucidated. In this review we highlight some of the recent literature on cardiolipin metabolism and Barth Syndrome.

Cancer-selective therapy of the future: apoptin and its mechanism of action.

Classical chemotherapy, that specifically targets rapidly proliferating cells, has been in existence for over eighty years and has proven to be fully successful in only a limited number of cancers. Thus, this review focuses on a novel, emerging approach for cancer therapy that uses alternative, and more unique features of cancer cells. This new approach facilitates the selective targeting of cancer, while sparing normal, non-transformed cells. Examples of molecules that kill cancer cells selectively are: apoptin, E4orf4, viral protein R (VpR), and Brevinin-2R. Below we focus on apoptin, a product of the third open reading frame (VP3) of the chicken anemia virus. Besides discussing apoptin's mechanism of action, we also provide concise insight into the biology of a chicken anemia virus infection. Since apoptin's cancer-selective toxicity depends on its nuclear localization, we broadly discuss mechanism(s) involved in its nuclear retention (both nuclear import and export). We also discuss recent findings on apoptin's molecular mechanism of action, with a focus on the role of Nur77 in apoptin's nucleo-cytoplasmic signaling. Finally, we compare the current findings on apoptin to the mechanism of cancer selective toxicity of E4orf4. In the 'summary' -section, besides highlighting important issues related to cancer-selective therapy, we also discuss concurrent approaches towards therapy personalization, particularly those related to the in vivo-, and real time cancer-therapy efficacy monitoring, using "lab-on-the-chip" and other emerging technologies.

Peptide-based approaches to treat asthma, arthritis, other autoimmune diseases and pathologies of the central nervous system.

In this review we focus on peptide- and peptidomimetic-based approaches that target autoimmune diseases and some pathologies of the central nervous system. Special attention is given to asthma, allergic rhinitis, osteoarthritis, and Alzheimer's disease, but other related pathologies are also reviewed, although to a lesser degree. Among others, drugs like Diacerhein and its active form Rhein, Pralnacasan, Anakinra (Kineret), Omalizumab, an antibody "BION-1", directed against the common beta-chain of cytokine receptors, are described below as well as attempts to target beta-amyloid peptide aggregation. Parts of the review are also dedicated to targeting of pathologic conditions in the brain and in other tissues with peptides as well as methods to deliver larger molecules through the "blood--brain barrier" by exploring receptor-mediated transport, or elsewhere in the body by using peptides as carriers through cellular membranes. In addition to highlighting current developments in the field, we also propose, for future drug targets, the components of the inflammasome protein complex, which is believed to initiate the activation of caspase- 1 dependent signaling events, as well as other pathways that signal inflammation. Thus we discuss the possibility of targeting inflammasome components for negative or positive modulation of an inflammatory response.