CD4 Knockout Mice Research Articles

Ecto-5'-Nucleotidase (CD73)-Mediated Formation of Adenosine Is Critical for the Striatal Adenosine A2A Receptor Functions

Adenosine is a neuromodulator acting through inhibitory A1 receptors (A1Rs) and facilitatory A2ARs, which have similar affinities for adenosine. It has been shown that the activity of intracellular adenosine kinase preferentially controls the activation of A1Rs, but the source of the adenosine activating A2ARs is unknown. We now show that ecto-5'-nucleotidase (CD73), the major enzyme able to convert extracellular AMP into adenosine, colocalizes with A2ARs in the basal ganglia. In addition to astrocytes, striatal CD73 is prominently localized to postsynaptic sites. Notably, CD73 coimmunoprecipitated with A2ARs and proximity ligation assays confirmed the close proximity of CD73 and A2ARs in the striatum. Accordingly, the cAMP formation in synaptosomes as well as the hypolocomotion induced by a novel A2AR prodrug that requires CD73 metabolization to activate A2ARs were observed in wild-type mice, but not in CD73 knock-out (KO) mice or A2AR KO mice. Moreover, CD73 KO mice displayed increased working memory performance and a blunted amphetamine-induced sensitization, mimicking the phenotype of global or forebrain-A2AR KO mice, as well as upon pharmacological A2AR blockade. These results show that CD73-mediated formation of extracellular adenosine is responsible for the activation of striatal A2AR function. This study points to CD73 as a new target that can fine-tune A2AR activity, and a novel therapeutic target to manipulate A2AR-mediated control of striatal function and neurodegeneration.

Involvement of microglial CD40 in murine retrovirus-induced peripheral neuropathy

B6 mice infected with LP-BM5 develop severe immunodeficiency (termed murine acquired immunodeficiency syndrome (MAIDS)) and peripheral neuropathy. To determine whether microglial CD40 is involved in LP-BM5-induced peripheral neuropathy, B6-CD40 knockout (KO) mice and B6-CD40 KO mice adoptively transferred either total leukocytes or B cells were examined for behavioral sensitivity, tissue viral loads, cytokine responses, and the development of MAIDS. All three CD40 KO groups developed MAIDS, the severity of which was correlated with peripheral cytokine responses. CD40 KO mice displayed significantly reduced mechanical hypersensitivity post-infection compared to wild-type mice regardless of cell transfer. These findings support microglial CD40 involvement in LP-BM5-induced peripheral neuropathy.

B7h (ICOS-L) Maintains Tolerance at the Fetomaternal Interface

In a successful pregnancy, the semiallogeneic fetus is not rejected by the maternal immune system, which implies tolerance mechanisms protecting fetal tissues from maternal immune attack. Here we report that the ICOS-B7h costimulatory pathway plays a critical role in maintaining the equilibrium at the fetomaternal interface. Blockade of this pathway increased fetal resorption and decreased fetal survival in an allogeneic pregnancy model (CBA female × B6 male). Locally in the placenta, levels of regulatory markers such as IDO and TGF-β1 were reduced after anti-B7h monoclonal antibody treatment, whereas levels of effector cytokines (eg, IFN-γ) were significantly increased. In secondary lymphoid organs, enhanced IFN-γ and granzyme B production (predominantly by CD8(+) T cells) was observed in the anti-B7h-treated group. The deleterious effect of B7h blockade in pregnancy was maintained only in CD4 knockout mice, not in CD8 knockout mice, which suggests a role for CD8(+) Tcells in immune regulation by the ICOS-B7h pathway. In accord, regulatory CD8(+) T cells (in particular, CD8(+)CD103(+) cells) were significantly decreased after anti-B7h monoclonal antibody treatment, and adoptive transfer of this subset abrogated the deleterious effect of B7h blockade in fetomaternal tolerance. Taken together, these data support the hypothesis that B7h blockade abrogates tolerance at the fetomaternal interface by enhancing CD8(+) effector response and reducing local immunomodulation mediated by CD8(+) regulatory T cells.

CD40‐CD40 ligand (CD40L) signaling modulates cardiac hypertrophy in angiotensin‐II induced hypertensive heart disease

The co‐stimulatory dyad CD40‐CD40L is involved in pro‐inflammatory activation of a wide range of immune and non‐immune cells. Here we investigated whether CD40‐CD40L interactions attenuate cardiac hypertrophy in hypertensive heart disease. Therefore CD40 knockout and wild type C57Bl6‐J mice were treated with angiotensin II (AngII) (2.5 mg/kg/day) for 4 weeks. AngII‐induced hypertension led to a significant increase in cardiac mass in Wt mice (+31%, P<0.01), but not in CD40 knockout mice (+10%, N.S.). Comparable changes were observed in diastolic wall thickness (echocardiography) and cardiomyocyte cross sectional area. To determine which CD40‐TRAF interactions were involved, the effect of mutations in the intracellular TRAF binding domains of CD40 was investigated. Relative to mice with intact downstream CD40 signaling, disruption of TRAF2/3/5, TRAF6 or both binding sites was associated with reduced hypertrophy (cardiac mass −24% for CD40‐TΔ2, −28% for CD40‐ TΔ6 and −26% in CD40‐TΔ2/6; p<0.05). Reduced hypertrophy was not associated with a decline in immune cell infiltration (CD45+ cells) or collagen content. Although the exact mechanism remains to be elucidated the present findings indicate that CD40‐ CD40L interactions are involved in the development of cardiac hypertrophy.

Flavonoid Apigenin Is an Inhibitor of the NAD+ase CD38

Metabolic syndrome is a growing health problem worldwide. It is therefore imperative to develop new strategies to treat this pathology. In the past years, the manipulation of NAD+ metabolism has emerged as a plausible strategy to ameliorate metabolic syndrome. In particular, an increase in cellular NAD+ levels has beneficial effects, likely because of the activation of sirtuins. Previously, we reported that CD38 is the primary NAD+ase in mammals. Moreover, CD38 knockout mice have higher NAD+ levels and are protected against obesity and metabolic syndrome. Here, we show that CD38 regulates global protein acetylation through changes in NAD+ levels and sirtuin activity. In addition, we characterize two CD38 inhibitors: quercetin and apigenin. We show that pharmacological inhibition of CD38 results in higher intracellular NAD+ levels and that treatment of cell cultures with apigenin decreases global acetylation as well as the acetylation of p53 and RelA-p65. Finally, apigenin administration to obese mice increases NAD+ levels, decreases global protein acetylation, and improves several aspects of glucose and lipid homeostasis. Our results show that CD38 is a novel pharmacological target to treat metabolic diseases via NAD+-dependent pathways.

CD8 Knockout Mice Are Protected from Challenge by Vaccination with WR201, a Live Attenuated Mutant ofBrucella melitensis

CD8+ T cells have been reported to play an important role in defense against B. abortus infection in mouse models. In the present report, we use CD8 knockout mice to further elucidate the role of these cells in protection from B. melitensis infection. Mice were immunized orally by administration of B. melitensis WR201, a purine auxotrophic attenuated vaccine strain, then challenged intranasally with B. melitensis 16M. In some experiments, persistence of WR201 in the spleens of CD8 knockout mice was slightly longer than that in the spleens of normal mice. However, development of anti-LPS serum antibody, antigen-induced production of γ-interferon (IFN-γ) by immune splenic lymphocytes, protection against intranasal challenge, and recovery of nonimmunized animals from intranasal challenge were similar between normal and knockout animals. Further, primary Brucella infection was not exacerbated in perforin knockout and Fas-deficient mice and these animals' anti-Brucella immune responses were indistinguishable from those of normal mice. These results indicate that CD8+ T cells do not play an essential role as either cytotoxic cells or IFN-γ producers, yet they do participate in a specific immune response to immunization and challenge in this murine model of B. melitensis infection.

Superior working memory and behavioural habituation but diminished psychomotor coordination in mice lacking the ecto-5′-nucleotidase (CD73) gene

Adenosine is an important neuromodulator in the central nervous system involved in the regulation of wakefulness, sleep, learning and memory, fear and anxiety as well as motor functions. Extracellular adenosine is synthesized by the cell-surface ectoenzyme ecto-5'-nucleotidase (CD73) from 5'-adenosine monophosphate. While CD73 is widely expressed throughout the mammalian brain, its specific role for behaviour is poorly understood. We examined spatial working memory, emotional responses, motor coordination and motor learning as well as behavioural habituation in mice with a targeted deletion of CD73. CD73 knockout (CD73-/-) mice exhibit enhanced spatial working memory in the Y-maze and enhanced long-term behavioural habituation in the open field. Furthermore, impaired psychomotor coordination on the accelerating rotarod was found in CD73-/- mice. No changes in motor learning and/or anxiety-like behaviour were evident in CD73-/- mice. Our data provide evidence for a role of CD73 in the regulation of learning and memory and psychomotor coordination. Our results might be important for the evaluation of adenosine neuromodulators as possible treatments to ameliorate cognitive and motor deficits associated with neurodegenerative diseases.

Altered CD38/Cyclic ADP-Ribose Signaling Contributes to the Asthmatic Phenotype

CD38 is a transmembrane glycoprotein expressed in airway smooth muscle cells. The enzymatic activity of CD38 generates cyclic ADP-ribose from β-NAD. Cyclic ADP-ribose mobilizes intracellular calcium during activation of airway smooth muscle cells by G-protein-coupled receptors through activation of ryanodine receptor channels in the sarcoplasmic reticulum. Inflammatory cytokines that are implicated in asthma upregulate CD38 expression and increase the calcium responses to contractile agonists in airway smooth muscle cells. The augmented intracellular calcium responses following cytokine exposure of airway smooth muscle cells are inhibited by an antagonist of cyclic ADP-ribose. Airway smooth muscle cells from CD38 knockout mice exhibit attenuated intracellular calcium responses to agonists, and these mice have reduced airway response to inhaled methacholine. CD38 also contributes to airway hyperresponsiveness as shown in mouse models of allergen or cytokine-induced inflammatory airway disease. In airway smooth muscle cells obtained from asthmatics, the cytokine-induced CD38 expression is significantly enhanced compared to expression in cells from nonasthmatics. This differential induction of CD38 expression in asthmatic airway smooth muscle cells stems from increased activation of MAP kinases and transcription through NF-κB, and altered post-transcriptional regulation through microRNAs. We propose that increased capacity for CD38 signaling in airway smooth muscle in asthma contributes to airway hyperresponsiveness.

Activation of Parenchymal CD47 Promotes Renal Ischemia-Reperfusion Injury

Ischemia-reperfusion injury (IRI) contributes to decreased allograft function and allograft rejection in transplanted kidneys. Thrombospondin-1 is a stress protein typically secreted in response to hypoxia and the ligand activator for the ubiquitously expressed receptor CD47. The function of activated CD47 in IRI remains completely unknown. Here, we found that both CD47 and its ligand thrombospondin-1 were upregulated after renal IRI in mice. CD47-knockout mice were protected against renal dysfunction and tubular damage, suggesting that the development of IRI requires intact CD47 signaling. Chimeric CD47-knockout mice engrafted with wild-type hematopoietic cells had significantly lower serum creatinine and less tubular damage than wild-type controls after IRI, suggesting that CD47 signaling in parenchymal cells predominantly mediates renal damage. Treatment with a CD47-blocking antibody protected mice from renal dysfunction and tubular damage compared with an isotype control. Taken together, these data imply that CD47 on parenchymal cells promotes injury after renal ischemia and reperfusion. Therefore, CD47 blockade may have therapeutic potential to prevent or suppress ischemia-reperfusion-mediated damage.

Differential lumbar spinal cord mononuclear cell responses among wild type, CD4 knockout, and CD40 knockout mice in spinal nerve L5 transection-induced neuropathic pain (54.17)

Abstract We have previously demonstrated that both lumbar spinal cord-infiltrating CD4+ T cells and lumbar spinal cord microglial CD40 contribute to the maintenance of mechanical hypersensitivity in the murine model of neuropathic pain spinal nerve L5 transection (L5Tx). To further delineate the CD4 and CD40-mediated mechanisms involved in the development of L5Tx-induced neuropathic pain behaviors, we examined the lumbar spinal cord mononuclear cells of wild type (WT) BALB/c, BALB/c-CD4 knockout (KO), and BALB/c-CD40 KO mice in time course studies via flow cytometry. In WT mice, L5Tx significantly increased the total numbers of lumbar spinal cord mononuclear cells, microglial cells (CD45loCD11b+), and infiltrating leukocytes (CD45hi) in the ipsilateral side of the spinal cord on both days 3 and 7 post-surgery. Meanwhile, in CD4 KO mice, the only significant elevation in microglial cells was observed on day 7 post-L5Tx, and there were no increases in mononuclear cells and infiltrating leukocytes numbers post-L5Tx. On the other hand, in CD40 KO mice, L5Tx did not induce any of the changes observed in WT mice. Altogether, these data indicate that both CD4 and CD40 play a role in L5Tx-induced leukocyte infiltration into the lumbar spinal cord but have differential contributions to spinal cord microglial activation following peripheral nerve injury.

Potential contribution of the interaction between spinal cord-infiltrating Th1 cells and astrocytes to the development of nerve injury induced neuropathic pain (173.10)

Abstract We previously demonstrated that CD4+ T cells contribute to the maintenance of L5 spinal nerve transection (L5Tx)-induced neuropathic pain in BALB/c mice, and T-Bet+ Th1 cells were found to be the dominant subtype of CD4+ T cells within the lumbar spinal cord following L5Tx. To investigate the specific downstream responses mediated by these infiltrating Th1 cells, we examined the cytokine expression of the spinal cord-infiltrating CD4+ T cells via flow cytometry. At day 7 post-L5Tx, the peak time for detecting the lumbar infiltrating CD4+ T cells, there were trends indicating increases in the numbers of IFNγ+ and TNFα+ lumbar spinal cord-infiltrating CD4+ T cells in the L5Tx group compared to the sham group. Further, we examined the expression of glial fibrillary acidic protein (GFAP), an indication of the level of astrocytic activation, in the L5 spinal cord via immunohistochemistry. As expected, in wild type BALB/c mice, L5Tx induced an increase in GFAP expression in the ipsilateral side of the spinal cord compared to sham-operated mice 7 days post-surgery. This increase appeared to be reduced in CD4 knockout mice post-L5Tx. Altogether our data suggest the involvement of the Th1 cytokines IFNγ and TNFα in the maintenance of L5Tx-induced neuropathic pain, which may have potential role in regulating spinal cord astrocyte activation.

CD73-generated adenosine limits immunopathology during acute Toxoplasma gondii infection (164.17)

Abstract As an obligate intracellular pathogen, the apicomplexan parasite Toxoplasma gondii elicits robust innate and adaptive immune responses that must be limited to prevent immunopathology. The breakdown of extracellular ATP to adenosine by the cell-surface enzyme CD73 plays an important role in the resolution of inflammation. The role of extracellular adenosine in the immune response to T. gondii infection has not been previously elucidated. In comparison to wildtype C57BL/6 mice, CD73-knockout mice infected with T. gondii by interperitoneal injection were highly susceptible to immune-mediated pathology, with significantly increased morbidity and mortality associated with marked infiltration of neutrophils and T cells into the peritoneal cavity. Peritoneal exudate cells from infected CD73KO mice generated higher levels of the inflammatory mediators nitric oxide, TNF-alpha, and IL1-beta, without enhanced parasite killing or clearance. The increased morbidity and mortality seen in CD73KO mice could be rescued by treating mice with the broad spectrum adenosine receptor agonist 5'-N-ethylcarboxamido adenosine. In addition, mice deficient in the adenosine receptor A2A were more susceptible to immunopathology during intraperitoneal infection with T. gondii compared to wildtype mice. Thus extracellular adenosine is a key molecule that regulates the immune response to an intracellular pathogen and promotes host survival.

5′‐Ectonucleotidase‐knockout mice lack non‐REM sleep responses to sleep deprivation

Adenosine and extracellular adenosine triphosphate (ATP) have multiple physiological central nervous system actions including regulation of cerebral blood flow, inflammation and sleep. However, their exact sleep regulatory mechanisms remain unknown. Extracellular ATP and adenosine diphosphate are converted to adenosine monophosphate (AMP) by the enzyme ectonucleoside triphosphate diphosphohydrolase 1, also known as CD39, and extracellular AMP is in turn converted to adenosine by the 5'-ectonuleotidase enzyme CD73. We investigated the role of CD73 in sleep regulation. Duration of spontaneous non-rapid eye movement sleep (NREMS) was greater in CD73-knockout (KO) mice than in C57BL/6 controls whether determined in our laboratory or by others. After sleep deprivation (SD), NREMS was enhanced in controls but not CD73-KO mice. Interleukin-1 beta (IL1β) enhanced NREMS in both strains, indicating that the CD73-KO mice were capable of sleep responses. Electroencephalographic power spectra during NREMS in the 1.0-2.5 Hz frequency range was significantly enhanced after SD in both CD73-KO and WT mice; the increases were significantly greater in the WT mice than in the CD73-KO mice. Rapid eye movement sleep did not differ between strains in any of the experimental conditions. With the exception of CD73 mRNA, the effects of SD on various adenosine-related mRNAs were small and similar in the two strains. These data suggest that sleep is regulated, in part, by extracellular adenosine derived from the actions of CD73.

CD36 is Involved in Astrocyte Activation and Astroglial Scar Formation

Inflammation is an essential component for glial scar formation. However, the upstream mediator(s) that triggers the process has not been identified. Previously, we showed that the expression of CD36, an inflammatory mediator, occurs in a subset of astcotyes in the peri-infarct area where the glial scar forms. This study investigates a role for CD36 in astrocyte activation and glial scar formation in stroke. We observed that the expression of CD36 and glial fibrillary acidic protein (GFAP) coincided in control and injured astrocytes and in the brain. Furthermore, GFAP expression was attenuated in CD36 small interfering RNA transfected astrocytes or in the brain of CD36 knockout (KO) mice, suggesting its involvement in GFAP expression. Using an in-vitro model of wound healing, we found that CD36 deficiency attenuated the proliferation of astrocytes and delayed closure of the wound gap. Furthermore, stroke-induced GFAP expression and scar formation were significantly attenuated in the CD36 KO mice compared with wild type. These findings identify CD36 as a novel mediator for injury-induced astrogliosis and scar formation. Targeting CD36 may serve as a potential strategy to reduce glial scar formation in stroke.

Use of Praziquantel as an Adjuvant Enhances Protection and Tc-17 Responses to Killed H5N1 Virus Vaccine in Mice

BackgroundH5N1 is a highly pathogenic influenza A virus, which can cause severe illness or even death in humans. Although the widely used killed vaccines are able to provide some protection against infection via neutralizing antibodies, cytotoxic T-lymphocyte responses that are thought to eradicate viral infections are lacking.Methodology/Principal FindingsAiming to promote cytotoxic responses against H5N1 infection, we extended our previous finding that praziquantel (PZQ) can act as an adjuvant to induce IL-17-producing CD8+ T cells (Tc17). We found that a single immunization of 57BL/6 mice with killed viral vaccine plus PZQ induced antigen-specific Tc17 cells, some of which also secreted IFN-γ. The induced Tc17 had cytolytic activities. Induction of these cells was impaired in CD8 knockout (KO) or IFN-γ KO mice, and was even lower in IL-17 KO mice. Importantly, the inoculation of killed vaccine with PZQ significantly reduced virus loads in the lung tissues and prolonged survival. Protection against H5N1 virus infection was obtained by adoptively transferring PZQ-primed wild type CD8+ T cells and this was more effective than transfer of activated IFN-γ KO or IL-17 KO CD8+ T cells.Conclusions/SignificanceOur results demonstrated that adding PZQ to killed H5N1 vaccine could promote broad Tc17-mediated cytotoxic T lymphocyte activity, resulting in improved control of highly pathogenic avian influenza virus infection.

Adenosine-mediated dermal fibrosis and Fli-1 expression in CD39 and CD73 knockout mice

Adenosine-mediated dermal fibrosis and Fli-1 expression in CD39 and CD73 knockout mice

Social memory, amnesia, and autism: Brain oxytocin secretion is regulated by NAD+ metabolites and single nucleotide polymorphisms of CD38

Previously, we demonstrated that CD38, a transmembrane protein with ADP-ribosyl cyclase activity, plays a critical role in mouse social behavior by regulating the release of oxytocin (OXT), which is essential for mutual recognition. When CD38 was disrupted, social amnesia was observed in Cd38 knockout mice. The autism spectrum disorders (ASDs), characterized by defects in reciprocal social interaction and communication, occur either sporadically or in a familial pattern. However, the etiology of ASDs remains largely unknown. Therefore, the theoretical basis for pharmacological treatments has not been established. Hence, there is a rationale for investigating single nucleotide polymorphisms (SNPs) in the human CD38 gene in ASD subjects. We found several SNPs in this gene. The SNP rs3796863 (C>A) was associated with high-functioning autism (HFA) in American samples from the Autism Gene Resource Exchange. Although this finding was partially confirmed in low-functioning autism subjects in Israel, it has not been replicated in Japanese HFA subjects. The second SNP of interest, rs1800561 (4693C>T), leads to the substitution of an arginine (R) at codon 140 by tryptophan (W; R140W) in CD38. This mutation was found in four probands of ASD and in family members of three pedigrees with variable levels of ASD or ASD traits. The plasma levels of OXT in ASD subjects with the R140W allele were lower than those in ASD subjects lacking this allele. The OXT levels were unchanged in healthy subjects with or without this mutation. One proband with the R140W allele receiving intranasal OXT for approximately 3years showed improvement in areas of social approach, eye contact and communication behaviors, emotion, irritability, and aggression. Five other ASD subjects with mental deficits received nasal OXT for various periods; three subjects showed improved symptoms, while two showed little or no effect. These results suggest that SNPs in CD38 may be possible risk factors for ASD by abrogating OXT function and that some ASD subjects can be treated with OXT in preliminary clinical trials.

Abstract 200: CD40 Signaling Mediates Postischemic Inflammation, Oxidative Stress, And Tissue Injury Following Focal Cerebral Ischemia

Rationale: Although CD40/CD40 ligand (CD40L) signaling has been implicated in clinical and experimental ischemic strokes, the underlying mechanisms are largely unclear. Objective: We investigated how CD40 participates in the cellular and molecular events underlying the postischemic inflammation and oxidative stress that may contribute to the tissue damage during cerebral ischemia. Methods and Results: Wild-type (WT, n=164) and CD40 knockout mice (n=132) were subjected to middle cerebral artery occlusion (MCAO, 60 minutes) followed by reperfusion. We found that ischemia/reperfusion induced CD40 expression in the brain in a time-dependent manner, primarily localized to the microvascular endothelial cells in the early phase (6h) and then to the activated microglia in the later time (24h). The adhesion and infiltration of neutrophils as well as the activation and expansion of microglia induced by ischemia/reperfusion were inhibited in CD40-/- mice, which were time-dependently correlated with suppressing nuclear factor-kB activation and proinflammatory cytokines (IL-1β, TNFα) and adhesion molecules (E- and P-selectin, ICAM-1,MCP-1). Infarct volumes and mortality were reduced in CD40-/- mice at 72h after ischemia/reperfusion. Treatment with an inhibitor of either NADPH oxidase or COX-2, the known enzymes that contributes to the tissue damage, reduced ischemic brain injury in wild-type mice, but not in CD40-/- mice. In contrast, treatment with an inhibitor of inducible nitric oxide synthase (iNOS) further reduced tissue injury in CD40-/- mice. Consistently, ischemia/reperfusion-induced upregulation of NADPH oxidase (Nox2, and Nox4) and COX-2, but not iNOS, were attenuated in CD40-/- mice. Conclusions: The findings unveil an essential role for CD40 in the regulation of early molecular and cellular events leading to postischemic inflammation. Inhibition of CD40 signaling may be a valuable therapeutic approach to counteract the deleterious effects of postischemic inflammation.

Differential Lumbar Spinal Cord Responses among Wild Type, CD4 Knockout, and CD40 Knockout Mice in Spinal Nerve L5 Transection-Induced Neuropathic Pain

BackgroundOur previous studies have indicated that both lumbar spinal cord-infiltrating CD4+ T cells and microglial CD40 contribute to the maintenance of mechanical hypersensitivity in a murine model of neuropathic pain spinal nerve L5 transection (L5Tx). To further delineate the CD4 and CD40-mediated mechanisms involved in the development of L5Tx-induced neuropathic pain behaviors, we examined the lumbar spinal cord mononuclear cells of wild type (WT) BALB/c, BALB/c-CD4 knockout (KO), and BALB/c-CD40 KO mice via flow cytometry.ResultsIn WT mice, L5Tx induced significant but transient (at day 3 and/or day 7) increases of the total numbers of mononuclear cells, microglial cells (CD45loCD11b+), and infiltrating leukocytes (CD45hi) in the ipsilateral side of the spinal cord. In CD4 KO mice, significant elevation of microglia was detected only on day 7 post-L5Tx, while no significant increase in infiltrating leukocytes post-L5Tx was observed. CD40 KO mice did not exhibit any of the changes observed in WT mice. Furthermore, neutralizing CD40 antibody treatment indicated an early involvement of CD40 signaling in the development of L5Tx-induced mechanical hypersensitivity.ConclusionsAltogether, data indicate that both CD4 and CD40 play a role in L5Tx-induced leukocyte infiltration into the lumbar spinal cord but have differential contributions to spinal cord microglial activation following peripheral nerve injury.

Patients with CD36 Deficiency Are Associated with Enhanced Atherosclerotic Cardiovascular Diseases

The clustering of dyslipidemia, impaired glucose tolerance and hypertension increases the morbidity and mortality from cardiovascular events. A class B scavenger receptor, CD36, is a receptor for oxidized LDL and a transporter of long-chain fatty acids. Because of the impaired uptake of oxidized LDL in CD36-deficient macrophages and from the results of CD36 knockout mice, CD36 deficiency (CD36-D) was supposed to be associated with reduced risks for coronary artery disease (CAD); however, CD36-D patients are often accompanied by a clustering of coronary risk factors. The current study aimed to investigate the morbidity and severity of cardiovascular diseases in CD36-D patients. By screening for CD36 antigen on platelets and monocytes using FACS or the absent myocardial accumulation of 123I-BMIPP by scintigraphy, 40 patients with type I CD36-D were collected, the morbidity of CAD and their features of atherosclerotic cardiovascular diseases were observed. Screening for CD36-D in both CAD patients (n = 319) and healthy subjects (n = 1,239) were underwent. The morbidity of CAD was significantly higher in CD36-D patients than in the general population; 50% of patients (20 out of 40) had CAD identified by BMIPP scintigraphy and 37.5% (3 out of 8) by FACS screening, respectively. Three representative CD36-D cases demonstrated severe CAD and atherosclerosis. The frequency of CD36-D was three times higher in CAD patients than in healthy subjects (0.9% vs 0.3%, p < 0.0001). The morbidity of CAD is significantly higher in CD36-D patients suffering from severe atherosclerosis, implying that the status of CD36-D might be atherogenic.