Macrophages recruited via CCR2 produce insulin-like growth factor-1 to repair acute skeletal muscle injury

CC chemokine receptor 2 (CCR2) is essential to acute skeletal muscle injury repair. We studied the subpopulation of inflammatory cells recruited via CCR2 signaling and their cellular functions with respect to muscle regeneration. Mobilization of monocytes/macrophages (MOs/MPs), but not lymphocytes or neutrophils, was impaired from bone marrow to blood and from blood to injured muscle in Ccr2(-/-) mice. While the Ly-6C(+) but not the Ly-6C(-) subset of MOs/MPs was significantly reduced in blood, both subsets were drastically reduced in injured muscle of Ccr2(-/-) mice. Expression of insulin-like growth factor-1 (IGF-I) was markedly up-regulated in injured muscle of wild-type but not Ccr2(-/-) mice. IGF-I was strongly expressed by macrophages within injured muscle, more prominently by the Ly-6C(-) subset. A single injection of IGF-I, but not PBS, into injured muscle to replace IGF-I remarkably improved muscle regeneration in Ccr2(-/-) mice. CCR2 was not detected in myogenic cells or capillary endothelial cells in injured muscle to suggest its direct involvement in muscle regeneration or angiogenesis. We conclude that CCR2 is essential to acute skeletal muscle injury repair primarily by recruiting Ly-6C(+) MOs/MPs. Within injured muscle, these cells conduct phagocytosis, contribute to accumulation of intramuscular Ly-6C(-) macrophages, and produce a high level of IGF-I to promote muscle regeneration.

Pro-apoptotic Bax is the major and Bak an auxiliary effector in cytokine deprivation-induced mast cell apoptosis

The process of apoptosis in immune cells like mast cells is essential to regain homeostasis after an inflammatory response. The intrinsic pathway of apoptosis is ultimately controlled by the pro-apoptotic Bcl-2 family members Bax and Bak, which upon activation oligomerize to cause increased permeabilization of the mitochondria outer membrane leading to cell death. We examined the role of Bax and Bak in cytokine deprivation-induced apoptosis in mast cells using connective tissue-like mast cells and mucosal-like mast cells derived from bax^−/−, bak^−/− and bax^−/−bak^−/− mice. Although both Bax and Bak were expressed at readily detectable protein levels, we found a major role for Bax in mediating mast cell apoptosis induced by cytokine deprivation. We analyzed cell viability by propidium iodide exclusion and flow cytometry after deprivation of vital cytokines for each mast cell population. Upon cytokine withdrawal, bak^−/− mast cells died at a similar rate as wild type, whereas bax^−/− and bax^−/−bak^−/− mast cells were partially or completely resistant to apoptosis, respectively. The total resistance seen in bax^−/−bak^−/− mast cells is comparable with mast cells deficient of both pro-apoptotic Bim and Puma or mast cells overexpressing anti-apoptotic Bcl-2. These results show that Bax has a predominant and Bak a minor role in cytokine deprivation-induced apoptosis in both connective tissue-like and mucosal-like mast cells.

Andrographolide regulates epidermal growth factor receptor and transferrin receptor trafficking in epidermoid carcinoma (A-431) cells

BACKGROUND AND PURPOSE

Andrographolide is the active component of Andrographis paniculata, a plant used in both Indian and Chinese traditional medicine, and it has been demonstrated to induce apoptosis in different cancer cell lines. However, not much is known about how it may affect the key receptors implicated in cancer. Knowledge of how andrographolide affects receptor trafficking will allow us to better understand new mechanisms by which andrographolide may cause death in cancer cells.

EXPERIMENTAL APPROACH

We utilized the well-characterized epidermal growth factor receptor (EGFR) and transferrin receptor (TfR) expressed in epidermoid carcinoma (A-431) cells as a model to study the effect of andrographolide on receptor trafficking. Receptor distribution, the total number of receptors and surface receptors were analysed by immunofluorescence, Western blot as well as flow-cytometry respectively.

KEY RESULTS

Andrographolide treatment inhibited cell growth, down-regulated EGFRs on the cell surface and affected the degradation of EGFRs and TfRs. The EGFR was internalized into the cell at an increased rate, and accumulated in a compartment that co-localizes with the lysosomal-associated membrane protein in the late endosomes.

CONCLUSION AND IMPLICATIONS

This study sheds light on how andrographolide may affect receptor trafficking by inhibiting receptor movement from the late endosomes to lysosomes. The down-regulation of EGFR from the cell surface also indicates a new mechanism by which andrographolide may induce cancer cell death.

Augmenting DAF levels in vivo ameliorates experimental autoimmune encephalomyelitis

Recent studies in experimental autoimmune encephalomyelitis (EAE) have found that CNS injury in Daf1(-/-) mice is much greater than in wild types (WTs), suggesting that upregulating DAF levels in vivo might ameliorate disease. To test this, we generated a Daf1 transgenic (Tg) mouse which had elevated DAF levels on its cell surfaces. In by-stand C3b uptake assays, Daf1 Tg mouse erythrocytes took up less C3b on their surfaces than WT erythrocytes. When co-cultured with OT-II CD4(+) T cells together with OVA(323-339) peptide, Daf1 Tg mouse bone marrow derived dendritic cells (BM-DCs) produced less C5a and C3a than WT BM-DCs and stimulated a lesser T cell response. In MOG(35-55) immunization induced EAE model, Daf1 Tg mice exhibited delayed disease onset and decreased clinical scores compared to WTs. Histological analyses showed that there were less inflammation and demyelination in spinal cords in Daf1 Tg mice than those in WTs. In accordance with these results, Daf1 Tg mice had decreased MOG(35-55) specific Th1 and Th17 responses. These data provide further evidence that DAF suppresses autoreactive T cell responses in EAE, and indicate that augmenting its expression levels could be effective therapeutically in treating multiple sclerosis as well as other T cell mediated diseases.

Campylobacter fetus cellulitis in an immunocompromised patient: case report and review of the literature

Campylobacter fetus is an opportunist Gram-negative bacillus. The most frequent clinical manifestation is bacteriemia but it can also be responsable for soft tissue infections, endovascular infections, meningitis, peritonitis and thrombophlebitis. Campylobacter fetus cellulitis has been described, but rarely identified in subcutaneous puncture samples. We report a case of an immunocompromised patient with Campylobacter fetus bacteriemia associated with a soft tissue infection whose subcutaneous puncture also revealed the bacteria.

Measurement of total blood flow in the normal human retina using Doppler Fourier-domain optical coherence tomography

AIM

To measure total retinal blood flow in normal human eyes using Doppler Fourier-domain optical coherence tomography (FD-OCT).

METHODS

10 normal people aged 35 to 69 years were measured for the right eye using Doppler FD-OCT. Double circular scans around the optic nerve heads were used. Four pairs of circular scans that transected all retinal branch vessels were completed in 2 s. Total retinal blood flow was obtained by summing the flows in the branch veins. Measurements from the eight scans were averaged. Veins with diameters >33 microm were taken into account.

RESULTS

Total retinal blood flow could be measured in eight of 10 subjects: mean (SD) = 45.6 (3.8) microl/min (range 40.8 to 52.9 microl/min). The coefficient of variation for repeated measurements was 10.5%. Measured vein diameters ranged from 33.3 to 155.4 mum. The averaged flow speed was 19.3 (2.9) mm/s, which did not correlate with vessel diameter. There was no significant difference between flows in the superior and inferior retinal hemispheres.

CONCLUSIONS

Double circular scanning using Doppler FD-OCT is a rapid and reproducible method to measure total retinal blood flow. These flow values are within the range previously established by laser Doppler flowmetry.

The synthesis and anticancer activity of selected diketopiperazines

Six selected diketopiperazines, cyclo(Gly-Val), cyclo(Gly-D-Val), cyclo(Gly-Leu), cyclo(Gly-Ile), cyclo(Phe-Cys) and cyclo(Tyr-Cys), were synthesized via various synthetic routes. Their potential to inhibit cancer cell growth in HT-29, HeLa and MCF-7 cells was determined. Cyclo(Tyr-Cys) caused the greatest inhibition in cervical carcinoma cells with near equivalent activity against HT-29 and MCF-7 cells. The other cyclic dipeptides tested were effective in the inhibition of colon, cervical and breast carcinoma cells, respectively, but the percentage inhibition was lower than for cyclo(Tyr-Cys).

Clinical course and prognostic factors of clinical early IgA nephropathy

BACKGROUND

Immunoglobulin A nephropathy (IgAN) is prevalent in many countries including China. At the time of diagnosis many IgAN patients present with normal renal function, proteinuria of 0.4 g/d or less, and normal blood pressure and they are classified as clinically early IgAN patients. However, the natural history of clinically early IgAN and prognostic factors has not yet been clarified.

METHODS

We investigated 177 early IgAN patients (108 males and 69 females) followed up for a mean period of 111 +/- 43 months.

RESULTS

During the follow-up period among 177 clinically early IgAN patients, urinary abnormalities disappeared in 9% of the patients; increased proteinuria was present in 79 patients (46%). The prevalence of hypertension was 38% (68 patients), and 24% (43 patients) developed renal insufficiency. Poor renal outcome was associated with haematuria, urinary protein excretion index (UPEI, the product of urinary protein excretion at the time of renal biopsy and prebiopsy duration), and tubulointerstitial lesions.

CONCLUSION

Renal outcome is dismal in patients with clinically early IgAN. Haematuria, UPEI, and tubulointerstitial lesions could be useful markers of a progressive course.

Administration of intracoronary bone marrow mononuclear cells on chronic myocardial infarction improves diastolic function

BACKGROUND

Regeneration of the myocardium and improved ventricular function have been demonstrated in patients with acute myocardial infarction (MI) treated by intracoronary delivery of autologous bone marrow mononuclear cells (BMC) a few days after successful myocardial reperfusion by percutaneous coronary intervention (PCI); however, the effects of intracoronary cell infusion in chronic MI patients are still unknown.

AIMS

To investigate whether intracoronary infusion of BMC into the infarct-related artery in patients with healed MI could lead to improvement in left ventricular (LV) function.

METHODS

Among 47 patients with stable ischaemic heart disease due to a previous MI (13 (SD 8) months previously), 24 were randomised to intracoronary infusion of BMC (BMC group) and 23 to a saline infusion (control group) into the target vessel after successful PCI within 12 hours after chest pain occurred. LV systolic and diastolic function, infarct size and myocardial perfusion defect were assessed with the use of echocardiography, magnetic resonance imaging (MRI) or (201)Tl single-photon-emission computed tomography (SPECT) at baseline and repeated at the 6-month follow-up examination.

RESULTS

BMC treatment did not result in a significant increase in LV ejection fraction in any of the groups by any of the methods used, and the apparent tendency of an improvement was not statistically different between the two groups. The two groups also did not differ significantly in changes of LV end-diastolic and systolic volume, infarct size or myocardial perfusion. However, there was an overall effect of BMC transfer compared with the control group with respect to early/late (E/A) (p<0.001), early diastolic velocity/late diastolic (Aa) velocity (Ea/Aa) ratio (p = 0.002) and isovolumetric relaxation time (p = 0.038) after 6 months, as evaluated by tissue Doppler echocardiography. We noted no complications associated with BMS transfer.

CONCLUSION

Intracoronary transfer of autologous BMC in patients with healed MI did not lead to significant improvement of cardiac systolic function, infarct size or myocardial perfusion, but did lead to improvement in diastolic function.

Locally produced complement fragments C5a and C3a provide both costimulatory and survival signals to naive CD4+ T cells

Costimulatory signals are critical to T cell activation, but how their effects are mediated remains incompletely characterized. Here, we demonstrate that locally produced C5a and C3a anaphylatoxins interacting with their G protein-coupled receptors (GPCRs), C5aR and C3aR, on APCs and T cells both upstream and downstream of CD28 and CD40L signaling are integrally involved in T cell proliferation and differentiation. Disabling these interactions reduced MHC class II and costimulatory-molecule expression and dramatically diminished T cell responses. Importantly, impaired T cell activation by Cd80-/-Cd86-/- and Cd40-/- APCs was reconstituted by added C5a or C3a. C5aR and C3aR mediated their effects via PI-3 kinase-gamma-dependent AKT phosphorylation, providing a link between GPCR signaling, CD28 costimulation, and T cell survival. These local paracrine and autocrine interactions thus operate constitutively in naive T cells to maintain viability, and their amplification by cognate APC partners thus is critical to T cell costimulation.

Cortical demyelination in PML and MS: Similarities and differences

OBJECTIVE

To characterize pathologic changes in the cerebral cortex of patients with multiple sclerosis (MS) and progressive multifocal leukoencephalopathy (PML).

METHODS

Autopsy brain tissue was obtained from 13 patients with PML, 4 patients with MS, 2 patients with HIV encephalopathy, and 1 subject without neurologic pathology. Immunohistochemistry for myelin proteins, inflammatory cells, and neurofilaments was performed to evaluate the distribution of cortical lesions, their inflammatory activity, and neuritic pathology. Confocal microscopy was applied to examine pathologic changes in neurites in PML cortex.

RESULTS

Leukocortical, intracortical, and subpial patterns of cortical demyelination were represented in MS brain tissue. In PML brain tissue intracortical and leukocortical but not subpial lesions were observed. Cortical lesions in PML and MS contained fewer inflammatory cells than demyelinated areas in the white matter. Neuritic pathology in cortical PML lesions was represented by dystrophic and transected neurites. Pathologic modifications in neuritic processes in PML were more evident in highly inflamed white matter than in gray matter areas of demyelination, reminiscent of previous reports of neuritic pathology in MS. JC virus-infected cells were associated with PML white matter, leukocortical and intracortical lesions.

CONCLUSIONS

Cortical pathology represents a distinct feature of progressive multifocal leukoencephalopathy. Similarities and differences with regard to multiple sclerosis cortical pathology were noted and may be informative regarding the pathogenesis of both disorders.

Significant alterations of biodistribution and immune responses in Balb/c mice administered with adenovirus targeted to CD40(+) cells

CD40 ligation has been shown to promote antigen-presenting functions of dendritic cells, which express CD40 receptor. Here we reported significantly altered biodistribution and immune responses with the use of CD40-targeted adenovirus. Compared with unmodified adenovirus 5, the CD40-targeted adenovirus following intravenous administration (i.v.) resulted in increased transgene expressions in the lung and thymus, which normally do not take up significant amounts of adenovirus. Intradermal injection saw modified adenovirus being mainly processed in local draining lymph nodes and skin. Following intranasal administration (i.n.), neither unmodified nor targeted viruses were found to be in the liver or spleen, which predominantly took up the virus following i.v. administration. However, inadvertent infection of the brain was found with unmodified adenoviruses, with the second highest gene expression among 14 tissues examined. Importantly, such undesirable effects were largely ablated with the use of targeted vector. Moreover, the targeted adenovirus elicited more sustained antigen-specific cellular immune responses (up to 17-fold) at later time points (30 days post boosting), but also significantly hampered humoral responses irrespective of administration routes. Additional data suggest the skewed immune responses induced by the targeted adenoviruses were not due to the identity of the transgene but more likely a combination of overall transgene load and CD40 stimulation.