PRRX1+MSCs Enhance Mandibular Regeneration during Distraction Osteogenesis.

Bone defect (BD) caused by trauma, infection, congenital defects, or neoplasia is a major cause of physical limitation. Distraction osteogenesis (DO) is a highly effective procedure for bone regeneration, while the concrete mechanism remains unknown. In this study, canine DO and BD models of the mandible were established. The results of micro-computed tomography and histological staining revealed that DO led to an increased mineralized volume fraction and robust new bone formation; in contrast, BD demonstrated incomplete bone union. Mesenchymal stem cells (MSCs) from DO and BD calluses were isolated and identified. Compared with BD-MSCs, DO-MSCs were found to have a stronger osteogenic capability. Single-cell RNA sequencing analysis was further performed to comprehensively define cell differences between mandibular DO and BD calluses. Twenty-six clusters of cells representing 6 major cell populations were identified, including paired related homeobox 1-expressing MSCs (PRRX1+MSCs), endothelial cells (ECs), T cells, B cells, neutrophils, and macrophages. Interestingly, 2 subpopulations in PRRX1+MSCs in the DO group were found to express the marker of neural crest cells (NCCs) and were associated with the process of epithelial-mesenchymal transition. The immunofluorescence assay was performed to further corroborate these results in vivo and in vitro, experimentally validating that continuous distraction maintained the PRRX1+MSCs in an embryonic-like state. Finally, we used CRISPR/Cas9 to knock out (KO) PRRX1 in the context of DO, which significantly blunted the capability of jawbone regeneration, resulting in a diminished NCC-like program and reduction of new bone volume. In addition, the ability of osteogenesis, cell migration, and proliferation in cultured PRRX1KO MSCs was inhibited. Taken together, this study provides a novel, comprehensive atlas of the cell fates in the context of DO regeneration, and PRRX1+MSCs act essential roles.

[Effect and mechanism of PCSK9 on lectin-like oxidized low-density lipoprotein receptor-1 mediated oxidized low-density lipoprotein uptake by THP-1 derived macrophages].

Objective: To investigate the effect and mechanism of proprotein convertase subtilisin type 9 (PCSK9) on lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) mediated oxidized low-density lipoprotein (ox-LDL) uptake by mononuclear macrophage (THP-1) derived macrophages. Methods: THP-1 monocyte was incubated with PMA for 48 hours to induce the differentiation into macrophages. Macrophages were pretreated with human recombinant PCSK9 protein for 1 hour and incubated with ox-LDL for 24 hours to induce foam cells. Oil red O staining was used to observe the accumulation of lipid in the control group (foam cells) and groups treated with different concentrations of recombinant PCSK9 protein, and the intracellular cholesterol content was measured by enzyme method, and mRNA and protein expressions of LOX-1 were detected by real-time PCR and Western blot. The uptake of Dil-labeled oxidized low density lipoprotein (Dil-ox-LDL) was observed by fluorescence microscopy in control group (macrophage), PCSK9 protein treated group and PCSK9 protein plus anti-LOX-1 antibody and IgG antibody treated group. mRNA and protein expression of toll-like receptor 4 (TLR4), nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2) were detected in control and PCSK9 protein treated group in the absence and presence of TLR4 inhibitor (TAK-242), NF-κB inhibitor (PDTC). In addition, reactive oxygen species (ROS) production was evaluated in the absence or presence of COX-2 inhibitor (NS-398) or reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor (DPI). The mRNA and protein expression of LOX-1 in the control group (PCSK9 protein pretreated foam cells) and PCSK9 protein group in the absence or presence of TAK-242, PDTC, NS-398 and DPI respectively. Results: (1) The total optical density of intracellular lipid droplets, total cholesterol level, cholesterol ester level and cholesterol ester/total cholesterol ratio as well as expression of LOX-1 were significantly higher in PCSK9 group than those in control group (all P<0.05). (2) The fluorescence intensity of Dil-ox-LDL was significantly higher in PCSK9 group and PCSK9+IgG antibody group than in the control group (all P<0.05). The fluorescence intensity was significantly lower in PCSK9+anti-LOX-1 antibody group than in PCSK9 group and PCSK9+IgG antibody group (all P<0.05). (3) The expressions of TLR4, NF-κB and COX-2 were significantly higher in PCSK9 group than in control group (all P<0.05). The expressions of TLR4, NF-κB and COX-2 were significantly lower in PCSK9+TAK-242 group and PCSK9+PDTC group than in PCSK9 group (all P<0.05). The ROS level was significantly higher in PCSK9 group than in the control group (P<0.05). The ROS levels were significantly lower in PCSK9+NS-398 and PCSK9+DPI groups than in PCSK9 group (all P<0.05). (4) The expressions of LOX-1 mRNA and protein were lower in respective PCSK9 protein plus TAK-242, PDTC, NS-398 or DPI group than in PCSK9 protein alone (all P<0.05). Conclusion: PCSK9 may regulate LOX-1 mediated ox-LDL uptake by the THP-1 derived macrophage via TLR4/NF-κB/COX-2/ROS pathway.

Subtype-specific inherited predisposition to pemphigus in the Chinese population.

BACKGROUND: Pemphigus is a group of rare life-threatening mucocutaneous autoimmune diseases, presenting mainly as two subtypes: pemphigus vulgaris (PV) and pemphigus foliaceus (PF). Inherited predispositions to pemphigus have long been speculated but they remain poorly understood. OBJECTIVES: To identify common and specific nongenetic and genetic factors associated with pemphigus and its subtypes in the Chinese population. METHODS: A genome-wide association study (GWAS) was performed in 496 unrelated patients with pemphigus (including 365 with PV and 104 with PF) and 1105 controls without pemphigus. RESULTS: A sex preference was observed only in PV (57·5% female) and not in PF (47·1% female). For male patients only, the mean age at diagnosis was significantly lower for PV than for PF (P < 0·001). The strongest associated single-nucleotide polymorphisms are in the human leucocyte antigen (HLA) region: rs70993900 (PV; P = 1·5 × 10-45 ) and rs9469220 (PF; P = 1·1 × 10-8 ). HLA-DQB1*05:03 ranks at the top (P = 4·7 × 10-40 ; odds ratio 12·4) in both subtypes, with significantly different risk allele frequency (RAFPV = 34·2% vs. RAFPF = 18·8% vs. RAFcontrol = 4·4%), whereas HLA-DRB1*14:01 and HLA-DRB1*04:06 are PV specific. HLA-DQB1*03:03 and HLA-DQB1*03:02 show significant subtype specificity in opposite directions. All of these associations were validated in the replication series with 147 cases of pemphigus and 604 controls. Multiple novel non-HLA susceptibility loci were also identified in the GWAS. CONCLUSIONS: This study represents the largest GWAS on pemphigus in the Chinese population published to date, and has allowed us to identify HLA haplotypes significantly shared between or specific to the two main subtypes of pemphigus.

Treatment of large bone defects with a novel biological transport disc in non-vascular transport distraction osteogenesis.

The aim of this study was to investigate a potential novel biological transport disc that avoids secondary injury to the body and facilitates bone healing. Twenty-seven dogs were divided randomly into three groups: group A were treated with human bone morphogenetic protein 2 (BMP-2) modified bone mesenchymal stem cell (BMSC) sheets combined with freeze-dried bone allograft as biological transport disc; group B were treated with BMSC sheets combined with freeze-dried bone allograft as transport disc (control); and group C were treated with direct extension only (blank). There were nine dogs in each group. Non-vascular transport distraction osteogenesis was performed in groups A and B to repair the mandibular bone defects, and in group C only mandibular truncation surgery was performed. The regeneration of bone was evaluated through X-ray, haematoxylin and eosin assay, and immunohistochemistry. After 2, 4, and 8 weeks of distraction, new bone density values in group A were 49.00±1.16, 66.63±2.62, and 72.78±2.67, respectively, and these were significantly different to values in groups B (P=0.0005, P=0.0004, P=0.0012) and C (P<0.0005, P=0.0001, P=0.0003). The average grey value for BMP-2 expression in group A after 4 weeks of distraction was 195.63±4.45, which was significantly different when compared to groups B (P=0.0022) and C (P=0.0006). This novel biological transport disc represents an effective non-secondary injury method to enhance new bone formation in non-vascular transport distraction osteogenesis.

Genetic polymorphisms and tissue expression of interleukin-22 associated with risk and therapeutic response of gastric mucosa-associated lymphoid tissue lymphoma.

Chronic Helicobacter pylori-stimulated immune reactions determine the pathogenesis of gastric mucosa-associated lymphoid tissue (MALT) lymphoma. We aimed to explore the genetic predisposition to this lymphoma and its clinical implication. A total of 68 patients and 140 unrelated controls were genotyped for 84 single-nucleotide polymorphisms in genes encoding cytokines, chemokines and related receptors that play important roles in T cell-mediated gastrointestinal immunity. Five genotypes in IL-22, namely CC at rs1179246, CC at rs2227485, AA at rs4913428, AA at rs1026788 and TT at rs7314777, were associated with disease susceptibility. The former four genotypes resided in the same linkage disequilibrium block (r(2)=0.99) that conferred an approximately threefold higher risk. In vitro experiments demonstrated that co-culturing peripheral mononuclear cells or CD4(+) T cells with H. pylori stimulated the secretion of interleukin-22 (IL-22), and that IL-22 induced the expression of antimicrobial proteins, RegIIIα and lipocalin-2, in gastric epithelial cells. Furthermore, patients with gastric tissue expressing IL-22 were more likely to respond to H. pylori eradication (14/22 vs 4/19, P<0.006). We conclude that susceptibility of gastric MALT lymphoma is influenced by genetic polymorphisms in IL-22, the product of which is involved in mucosal immunity against H. pylori and associated with tumor response to H. pylori eradication.

Inhibition of inducible nitric oxide synthesis ameliorates liver ischemia and reperfusion injury induced transient increase in arterial stiffness.

PURPOSE: Hemodynamic instability is a frequent scenario after reperfusion of ischemic liver due to major liver resection and liver transplantation. Previously, we showed that liver ischemia/reperfusion (I/R) injury induced increases in reactive oxygen/nitrogen species and inducible nitric oxide synthase (iNOS) expression impaired cardiac contractility. In addition, nitric oxide (NO) generated via iNOS may have impacts on large arterial smooth muscle tone, causing transient changes in arterial stiffness and ventricular afterload. In this study, we aim to investigate associations between iNOS and transient alternation in arterial stiffness during liver I/R injury, and effects of treatments with 1,400W, a selective iNOS inhibitor, and L-NG nitroarginine methyl ester (L-NAME), a non-specific NOS inhibitor. METHODS: The arterial stiffness is evaluated using the pulse wave velocity (PWV(2)), measured by finding the means of two high-fidelity micromanometers positioned at the aortic root and left femoral artery. Liver ischemia was conducted by occluding both the hepatic artery and portal vein for 30 minutes, followed by 120 minutes of reperfusion. Studies were performed on male Sprague-Dawley rats in four groups: a sham-operated group, a liver I/R group, and those groups pretreated with 1,400W (N-[3-(aminomethyl)benzyl]acetamidine) or L-NAME. Serum NO metabolites, tumor necrosis factor-α (TNF-α) and methylguanidine (MG) were measured at baseline, 30 minutes of ischemia, and 120 minutes of reperfusion. RESULTS: Post-reperfusion arterial stiffness increased by ∼14% as compared with the baseline, along with increases in serum NO metabolites, TNF-α, and MG level (P < .05); 1,400W and L-NAME treatment reduces post-reperfusion arterial stiffness by ∼5% similarly. Treatments with 1,400W and L-NAME both attenuated I/R induced increases in serum TNF-α, MG, and NO metabolites level (P < .05). CONCLUSIONS: I/R-induced arterial stiffening was strongly associated with increased systemic inflammation. Comparable effects with treatments of 1,400W and L-NAME suggested that iNOS plays a dominant role in I/R-induced transient arterial stiffening.

N-acetylcysteine improves cardiac contractility and ameliorates myocardial injury in a rat model of lung ischemia and reperfusion injury.

OBJECTIVES: Lung ischemia and reperfusion (I/R) injury is the major complication subsequent to cardiopulmonary bypass surgery and lung transplantation. Lung I/R injury frequently induces cardiac dysfunction leading to significant mortality. So far, the literature on therapeutic interventions in cardiac dysfunction and myocardial injury is still scarce. In this study, we examined the efficacy of N-acetylcysteine (NAC) administration against lung I/R injury-induced cardiac dysfunction. METHODS: Lung ischemia was established by occluding the left lung hilum for 60 minutes, followed by 2 hours of reperfusion. Studies were performed in 3 groups: sham-operated (same surgical procedure except vessel occlusion; N = 8), lung I/R injury (N = 12), and NAC-administered group (N = 12). The cardiac function was assessed using simultaneous left ventricular (LV) pressure and volume measured via a high-fidelity pressure-volume catheter. Myocardial injury was assessed based on serum creatine kinase muscle brain fraction (CK-MB) and troponin I (cTnI) level, and lung injury based on the degree of protein concentration in lung lavage. We also examined the degrees of myocardial lipid peroxidation and hydroxyl radical production with and without NAC. RESULTS: During lung ischemia, LV stiffness increased with relative intact contractility. After 2 hours of reperfusion, LV contractility decreased with dilated and stiffened ventricle, along with apparent myocardial and lung injury. NAC administration effectively attenuated heart and lung injury, and ameliorated impaired LV contractility and stiffening resulting from lung I/R injury. CONCLUSIONS: NAC administration reduced lung I/R-induced increases in myocardial hydroxyl radical production and lipid peroxidation, and ameliorated LV contractility and stiffening.

Interferon-stimulated gene ISG12b2 is localized to the inner mitochondrial membrane and mediates virus-induced cell death.

Interferons (IFNs) are crucial for host defence against viruses. Many IFN-stimulated genes (ISGs) induced by viral infection exert antiviral effects. Microarray analysis of gene expression induced in liver tissues of mice on dengue virus (DENV) infection has led to identification of the ISG gene ISG12b2. ISG12b2 is also dramatically induced on DENV infection of Hepa 1-6 cells (mouse hepatoma cell line). Here, we performed biochemical and functional analyses of ISG12b2. We demonstrate that ISG12b2 is an inner mitochondrial membrane (IMM) protein containing a cleavable mitochondrial targeting sequence and multiple transmembrane segments. Overexpression of ISG12b2 in Hepa 1-6 induced release of cytochrome c from mitochondria, disruption of the mitochondrial membrane potential, and activation of caspase-9, caspase-3, and caspase-8. Treatment of ISG12b2-overexpressing Hepa 1-6 with inhibitors of pan-caspase, caspase-9, or caspase-3, but not caspase-8, reduced apoptotic cell death, suggesting that ISG12b2 activates the intrinsic apoptotic pathway. Of particular interest, we further demonstrated that ISG12b2 formed oligomers, and that ISG12b2 was able to mediate apoptosis through both Bax/Bak-dependent and Bax/Bak-independent pathways. Our study demonstrates that the ISG12b2 is a novel IMM protein induced by IFNs and regulates mitochondria-mediated apoptosis during viral infection.

Monoclonal antibody strategies to block angiogenesis.

Antibodies represent a unique class of therapeutics because of their high specificity towards a defined target antigen. Recent clinical success with antibody-based cancer therapeutics has led to an increase in the clinical development of these agents. Antibody therapeutics offer a promising approach for inhibiting new blood vessel formation (angiogenesis), which is associated with a variety of diseases, including cancer. In this review we will focus on angiogenesis-related mechanisms targeted by antibody-based therapeutics, with an emphasis on those studies where pre-clinical in vivo data is available.

Monoclonal antibodies directed to different regions of vascular endothelial cadherin extracellular domain affect adhesion and clustering of the protein and modulate endothelial permeability.

Vascular endothelial cadherin (VE-cadherin) is an endothelial cell-specific cadherin that plays an important role in the control of vascular organization. Blocking VE-cadherin antibodies strongly inhibit angiogenesis, and inactivation of VE-cadherin gene causes embryonic lethality due to a lack of correct organization and remodeling of the vasculature. Hence, inhibitors of VE-cadherin adhesive properties may constitute a tool to prevent tumor neovascularization. In this paper, we tested different monoclonal antibodies (mAbs) directed to human VE-cadherin ectodomain for their functional activity. Three mAbs (Cad 5, BV6, BV9) were able to increase paracellular permeability, inhibit VE-cadherin reorganization, and block angiogenesis in vitro. These mAbs could also induce endothelial cell apoptosis in vitro. Two additional mAbs, TEA 1.31 and Hec 1.2, had an intermediate or undetectable activity, respectively, in these assays. Epitope mapping studies show that BV6, BV9, TEA 1.31, and Hec 1.2 bound to a recombinant fragment spanning the extracellular juxtamembrane domains EC3 through EC4. In contrast, Cad 5 bound to the aminoterminal domain EC1. By peptide scanning analysis and competition experiments, we defined the sequences TIDLRY located on EC3 and KVFRVDAETGDVFAI on EC1 as the binding domain of BV6 and Cad 5, respectively. Overall, these results support the concept that VE-cadherin plays a relevant role on human endothelial cell properties. Antibodies directed to the extracellular domains EC1 but also EC3-EC4 affect VE-cadherin adhesion and clustering and alter endothelial cell permeability, apoptosis, and vascular structure formation.

[Observation on the changes in nasopharyngeal carcinoma patients' olfactory before and after radiotherapy].

OBJECTIVE: Detecting nasopharyngeal carcinoma (NPC) patients' olfactory before and after radiotherapy for investigating the infection of radiotherapy on these patients' olfactory. METHOD: 100 NPC patients' olfactory were detected before the start of radiotherapy and after the termination of therapy in 3, 6, 12, 24 and 36 months. RESULT: Patients' smell acuity decreased sharply 3 months after therapy, but varying degrees of recovery were noted in 6 and 12 months. However their smell acuity became worse in the following time. CONCLUSION: NPC patients' smell acuity can be profoundly affected by radiotherapy. And after radiotherapy, their smell acuity will decrease wave-likely and cannot fully recover.

Inhibition by diallyl trisulfide, a garlic component, of intracellular Ca(2+) mobilization without affecting inositol-1,4, 5-trisphosphate (IP(3)) formation in activated platelets.

Garlic has been used in herbal medicine for thousands of years. Some reports have shown that garlic has protective effects against atherosclerosis and inhibits platelet function. In this study, we investigated the mechanism by which diallyl trisulfide (DT), a component of garlic, inhibits platelet function. DT inhibited platelet aggregation and Ca(2+) mobilization in a concentration-dependent manner without increasing intracellular cyclic AMP and cyclic GMP. DT also had no inhibitory effects on thromboxane A(2) (TXA(2)) production in cell-free systems. Collagen-related peptide (CRP)-induced Ca(2+) mobilization is regulated by phospholipase C-gamma2 (PLC-gamma2) activation. We evaluated the effect of DT on tyrosine phosphorylation of PLC-gamma2 and the production of inositol-1,4,5-trisphosphate (IP(3)). DT at concentrations that inhibited platelet aggregation and Ca(2+) mobilization had no effects on tyrosine phosphorylation of PLC-gamma2 or on the formation of IP(3) induced by CRP. Similar results were obtained with thrombin-induced platelet activation. DT inhibited platelet aggregation and Ca(2+) mobilization induced by thrombin without affecting the production of IP(3.) We then evaluated the effect of DT on the binding of IP(3) to its receptor. DT at high concentrations partially blocked the binding of IP(3) to its receptor. Taken together, our findings suggest that the agent suppresses Ca(2+) mobilization at a step distal to IP(3) formation. DT may provide a good tool for investigating Ca(2+) mobilization.

[Skeletal dysplasia and osteoporosis due to inadequate athletic].

Athletic load is an important factor that has an influence on the growth, development and mature of skeleton. In patients who had the functional disorder of hip joint resulting from hip diseases during their teen-ages, skeletal dysplasia and osteoporosis would occur. The present paper reported 30 cases of unilateral hip disorder. The patients were 20 men and 10 women whose age ranged from 2 to 20 years. The course of disease lasted 2 to 49 years. Their primary diseases included suppurant hip arthritis (16 cases), tuberculous arthritis of hip (10 cases), and others (4 cases). The follow-up study revealed fixed hip joint in 18 cases, positive Thomas sign in 22 cases, limited motion of hip joint in 12 cases, and unequal length of lower extremities in 25 cases; at the same time X-ray films showed ankylosis of hip at normal position in 10 patients, dislocation with ankylosis of hip in 13 patients, arthritic disorder of hip in 7 patients, skeletal dysplacia of ischium and pubis in 18 patients, and skeletal dysplasia of femur in 22 patients. All patients had osteoporosis. A discussion about the basic mechanism for skeletal dysplasia and osteoporosis following inadequate athletic load is presented. We believe that the skeletal dysplasia and osteoporosis in our group were caused by the diseases that led to inadequate athletic load. Therefore it is important to provide a thorough treatment and help the patients to their strength to be loaded in time.

Monoclonal antibody to vascular endothelial-cadherin is a potent inhibitor of angiogenesis, tumor growth, and metastasis.

Vascular endothelial-cadherin (VE-cad) is an endothelial cell-specific adhesion molecule that is crucial for proper assembly of vascular tubes. Here we show that a monoclonal antibody (BV13) directed to the extracellular region of VE-cad inhibits formation of adherens junctions and capillary-like structures by endothelial cells and blocks angiogenesis in the mouse cornea and in Matrigel plugs in vivo. Systemic administration of BV13 markedly decreases the growth of s.c. Lewis lung or human A431 epidermoid tumors and strongly suppresses the growth of Lewis lung metastases. These data demonstrate that VE-cad is essential for postnatal angiogenesis and thus validate VE-cad as a novel target for antiangiogenesis agents.

Activation of a cAMP pathway and induction of melanogenesis correlate with association of p16(INK4) and p27(KIP1) to CDKs, loss of E2F-binding activity, and premature senescence of human melanocytes.

There is strong evidence that the senescent phenotype, whether induced by telomere shortening, oxidative damage, or oncogenic stimuli, is an important tumor suppressive mechanism. The melanocyte is a cell of neural crest origin that produces the pigment melanin and can develop into malignant melanomas. To understand how malignant cells escape senescence, it is first crucial to define what genes control senescence in the normal cell. Prolonged exposure to high levels of cAMP results in accumulation of melanin and terminal differentiation of human melanocytes. Here we present evidence that activation of a cAMP pathway correlates with multiple cellular changes in these cells: (1) increased expression of the transcription factor microphthalmia; (2) increased melanogenesis; (3) increased association of the cyclin-dependent kinase inhibitors (CDK-Is) p27(KIP1) and p16(INK4) with CDK2 and CDK4, respectively; (4) failure to phosphorylate the retinoblastoma protein (pRB); (5) decreased expression of E2F1, E2F2, and E2F4 proteins; (6) loss of E2F DNA-binding activity; and (7) phenotypic changes characteristic of senescent cells. Senescent melanocytes have potent E2F inhibitory activity, because extracts from these cells completely abolished E2F DNA-binding activity that was present in extracts from the early proliferative phase. We propose that increased activity of the CDK-Is p27 and p16 and loss of E2F activity in human melanocytes characterize a senescence program activated by the cAMP pathway. Disruption of cAMP-mediated and melanogenesis-induced senescence may cause immortalization of human melanocytes, an early step in the development of melanomas.

Gene expression and production of the monokine induced by IFN-gamma (MIG), IFN-inducible T cell alpha chemoattractant (I-TAC), and IFN-gamma-inducible protein-10 (IP-10) chemokines by human neutrophils.

Monokine induced by IFN-gamma (MIG), IFN-inducible T cell alpha chemoattractant (I-TAC), and IFN-gamma-inducible protein of 10 kDa (IP-10) are related members of the CXC chemokine subfamily that bind to a common receptor, CXCR3, and that are produced by different cell types in response to IFN-gamma. We have recently reported that human polymorphonuclear neutrophils (PMN) have the capacity to release IP-10. Herein, we show that PMN also have the ability to produce MIG and to express I-TAC mRNA in response to IFN-gamma in combination with either TNF-alpha or LPS. While IFN-gamma, alone or in association with agonists such as fMLP, IL-8, granulocyte (G)-CSF and granulocyte-macrophage (GM)-CSF, failed to influence MIG, IP-10, and I-TAC gene expression, IFN-alpha, in combination with TNF-alpha, LPS, or IL-1beta, resulted in a considerable induction of IP-10 release by neutrophils. Furthermore, IL-10 and IL-4 significantly suppressed the expression of MIG, IP-10, and I-TAC mRNA and the extracellular production of MIG and IP-10 in neutrophils stimulated with IFN-gamma plus either LPS or TNF-alpha. Finally, supernatants harvested from stimulated PMN induced migration and rapid integrin-dependent adhesion of CXCR3-expressing lymphocytes; these activities were significantly reduced by neutralizing anti-MIG and anti-IP-10 Abs, suggesting that they were mediated by MIG and IP-10 present in the supernatants. Since MIG, IP-10, and I-TAC are potent chemoattractants for NK cells and Th1 lymphocytes, the ability of neutrophils to produce these chemokines might contribute not only to the progression and evolution of the inflammatory response, but also to the regulation of the immune response.

Hyaluronan fragments synergize with interferon-gamma to induce the C-X-C chemokines mig and interferon-inducible protein-10 in mouse macrophages.

Hallmarks of chronic inflammation and tissue fibrosis are increased influx of activated inflammatory cells, mediator release, and increased turnover and production of the extracellular matrix (ECM). Recent evidence has suggested that fragments of the ECM component hyaluronan play a role in chronic inflammation by inducing macrophage expression of chemokines. Interferon-gamma (IFN-gamma), an important regulator of macrophage functions, has been shown to induce the C-X-C chemokines Mig and IP-10. These chemokines affect T-cell recruitment and inhibit angiogenesis. The purpose of this investigation was to determine the effect of hyaluronan (HA) on IFN-gamma-induced Mig and IP-10 expression in mouse macrophages. We found a marked synergy between HA and IFN-gamma on Mig and IP-10 mRNA and protein expression in mouse macrophages. This was most significant with Mig, which was not induced by HA alone. The synergy was specific for HA, was not dependent on new protein synthesis, was not mediated by tumor necrosis factor-alpha, was selective for Mig and IP-10, and occurred at the level of gene transcription. These data suggest that the ECM component HA may influence chronic inflammatory states by working in concert with IFN-gamma to alter macrophage chemokine expression.

Sister chromatid exchange induced by chromium compounds in human lymphocytes.

The objective of this study was to study was to compare chromium (Cr), nickel-chromium (Ni-Cr), and control groups for sister chromatid exchange (SCE) in lymphocytes to obtain an understanding of the mutagenic effect of Cr(VI) in humans. Subjects totaled 91 persons from the 3 groups, including 14 Cr and 34 Ni-Cr electroplating workers and 43 control group members. Results showed that blood and urine Cr concentrations were highest among Cr workers (11.39 microg/l, 14.7 microg/g creatinine), next highest among Ni-Cr workers (5.28 microg/l, 6.2 microg/g creatinine), and lowest among the control group (2.36 microg/l, NA). After adjustment for smoking habits, SCE/cell values were 10.6, 9.4, and 8.3 for Cr workers, Ni-Cr workers, and controls, respectively. A synergetic effect was shown on HFC (high-frequency cells) percentages for Cr workers who also smoked. Odds ratios were 31.78 and 3.66 that Cr and Ni-Cr workers would have higher HFC percentages than the control group, respectively. The authors conclude that SCE in lymphocytes is useful for evaluation of the biological effects of environmental mutagens.