Costimulatory blockade-mediated lung allograft acceptance is abrogated by overexpression of Bcl-2 in the recipient

Lung allografts are considered to be more immunogenic than other solid organs. Little is known about the effectiveness of immunosuppressive regimens after lung transplantation. Herein, we describe a novel model of murine vascularized orthotopic lung transplantation we used to study the effects of costimulatory blockade on lung rejection. Transplants were performed in the Balb --> B6 strain combination. Recipients were either not immunosuppressed or received perioperative CD40/CD40L and CD28/B7 costimulatory blockade. Nonimmunosupressed Balb/c --> B6 lung transplants had severe acute rejection 7 days after transplantation and CD8(+) T cells outnumbered CD4(+) T cells within the allografts. Alternatively, B6 recipients that received perioperative costimulatory blockade had minimal inflammation and there were nearly equal numbers of CD8(+) and CD4(+) T cells in these grafts. Approximately one third of graft-infiltrating CD4(+) T cells expressed Foxp3. CD4(+) T cells isolated from these grafts induced apoptosis of alloreactive CD8(+) T cells that were stimulated with donor splenocytes in vitro. In contrast with wild-type B6 recipient mice, we observed severe rejection of Balb/c lungs 7 days after transplantation into Bcl-2 transgenic B6 recipients that had received costimulatory blockade. CD8(+) T cells outnumbered CD4(+) T cells in these immunosuppressed Bcl-2 transgenic recipients and, compared with immunosuppressed wild-type B6 recipients, a lower percentage of graft-infiltrating CD4(+) T cells expressed Foxp3, and a higher percentage of graft-infiltrating CD8(+) T cells expressed intereferon-gamma. Thus, our results show that perioperative blockade of the CD40/CD40L and CD28/B7 costimulatory pathways markedly ameliorates acute rejection of lung allografts in wild type but not Bcl-2 transgenic recipients.

Monocyte differentiation is controlled by MyD88 after mouse orthotopic lung transplantation

In lung grafts, ischemia-reperfusion signals rapidly induce the recruitment and differentiation of host monocytes into macrophages and dendritic cells. The nature of ischemia-reperfusion signals are antigen independent, but have been hypothesized to initiate Toll-like receptor (TLR) and interleukin (IL)-1R-mediated signaling pathways that are thought to potentiate alloimmune responses. We wondered whether MyD88, an adaptor molecule critical for both TLR and IL-1R-mediated inflammatory responses, regulated monocyte differentiation in a mouse model of vascularized orthotopic lung transplantation. Orthotopic left lung transplants were performed in the following syngeneic combinations: CD45.1(+) B6 --> CD45.2(+) MyD88(-/-) and CD45.1(+) B6 --> CD45.2(+) B6. One day later, recipient-derived dendritic cells and macrophage numbers were assessed in the bronchiolar lavage by FACS analysis. Compared with the bronchiolar lavage of wildtype recipients, MyD88(-/-) recipients had lower numbers of dendritic cells in lung graft airways that were of recipient origin. Lower numbers of newly differentiated lung graft dendritic cells was coincident with the appearance of higher numbers of undifferentiated monocytes in the lung airways of MyD88(-/-) recipients as compared with wild-type recipients. Moreover, adoptive transfer experiments demonstrated that MyD88(-/-) monocytes were poorer at differentiating into lung dendritic cells as compared with wild-type monocytes. Taken together, these data show that MyD88 regulates graft-infiltrating monocyte differentiation and suggests a mechanism by which TLR/IL-1R-signaling pathways control adaptive responses in lung allografts through controlling monocyte fate.

A role for candidate tumor-suppressor gene TCEAL7 in the regulation of c-Myc activity, cyclin D1 levels and cellular transformation

The pathophysiological mechanisms that drive the development and progression of epithelial ovarian cancer remain obscure. Recently, we identified TCEAL7 as a transcriptional regulatory protein often downregulated in epithelial ovarian cancer. However, the biological significance of such downregulation in cancer is not currently known. Here, we show that TCEAL7 is downregulated frequently in many human cancers and that in immortalized human ovarian epithelial cells this event promotes anchorage-independent cell growth. Mechanistic investigations revealed that TCEAL7 associates with cyclin D1 promoter containing Myc E-box sequence and transcriptionally represses cyclin D1 expression. Moreover, downregulation of TCEAL7 promotes DNA-binding activity of Myc-Max, and upregulates the promoter activity of c-Myc-target gene, ornithine decarboxylase (ODC), whereas enhanced expression of TCEAL7 inhibits Myc-induced promoter activity of ODC. Our findings suggest that TCEAL7 may restrict ovarian epithelial cell transformation by limiting Myc activity. These results also suggest a potential, alternative mechanism by which c-Myc activity may be deregulated in cancer by the downregulation of TCEAL7.

Physiological effects of ultrasound mist on fibroblasts

BACKGROUND

Chronic wounds present an increasing challenge in healthcare and consume a substantial portion of healthcare cost. Although new treatments have been developed, treatment success has not been improved greatly. Ultrasound has long been employed in medicine. Its unique ability to deliver energy makes it an ideal candidate as a wound care modality. We proposed that ultrasound would differentially affect intracellular signaling pathways and, with the ability to assess this effect using a noncontact form of ultrasound, were provided with a means to test this proposal.

METHODS

The cellular morphology, mitogenic activities, expression of keratinocyte growth factor (KGF) and transforming growth factor beta-1 (TGF-beta1), and activation of extracellular regulated kinase (ERK) and c-Jun N-terminal kinase (JNK) signaling pathways of dermal fibroblasts were studied after ultrasound treatment. Untreated and scrape-wounded fibroblasts were utilized as controls.

RESULTS

There was no difference in morphology observed, except for vacuolization in ultrasound-treated fibroblasts. Mitogenic activities were similar between ultrasound-treated and scrape-wounded fibroblasts. Ultrasound-treated fibroblasts exhibited a much earlier increase in KGF expression, ERK activation, and JNK activation. The ERK/JNK ratio was increased markedly in ultrasound-treated fibroblasts.

CONCLUSION

We conclude that ultrasound induces cellular responses that may be beneficial to wound healing.

CVX-045: A novel thrombospondin-1 (TSP-1) mimetic CovX-Body that potentiates chemotherapy in preclinical colon cancer models

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Background: TSP-1 reduces angiogenesis and tumor growth in vivo, and induces endothelial cell apoptosis in vitro. CVX-045 was produced by fusing a peptide derived from TSP-1, known to have anti-vascular activity, to a proprietary monoclonal antibody. CVX-045 possesses the potency and specificity of the TSP-1 mimetic peptide, along with the advantageous PK of an antibody. Methods: Anti-tumor activity of CVX-045 was evaluated in A549, A431, and HT-29 human adenocarcinoma xenograft models. Cells were implanted SC in female nu/nu mice, and tumors were staged to 300–400 mm3 prior to initiation of weekly treatments: CVX-045 IV 10–30 mg/kg; 5-FU or CPT-11 IP 100 mg/kg. Results: CVX-045 (10 mg/kg) significantly reduced A549 and A431 tumor growth 73% (day 49) and 51% (day 22), respectively, but was not effective in the HT-29 xenograft (10 or 30 mg/kg). CVX-045 demonstrated significant anti-vascular activity, reducing tumor microvessel density 51% in A549, 49% in A431, and 36% in HT-29 xenografts. CVX-045 (30 mg/kg) plus 5- FU significantly decreased HT-29 tumor growth 70% and microvessel density 61.2% on day 30 (both P<0.01), effects significantly greater than either agent alone. Co-treatment with CVX-045 (30 mg/kg) plus CPT-11 decreased HT-29 tumor volume 91% on day 28 (P<0.001), also significantly greater than either agent alone. As a surrogate measurement of survival, mice remained on treatment until tumors reached 2000 mm3. CPT-11 alone extended the time to reach tumor load from day 28 to day 39, while the combination of CPT-11 with CVX-045 extended this further to day 60. Conclusions: CVX-045 exhibits significant anti-angiogenic activity in several tumor models and enhances anti-tumor activity in combination with standard chemotherapies in a highly aggressive colon tumor model.

No significant financial relationships to disclose.

Three-dimensional visualization of microvessel architecture of whole-mount tissue by confocal microscopy

The three-dimensional architecture of the nascent microvascular network is a critical determinant of vascular perfusion in the setting of regenerative growth, vasculopathies and cancer. Current methods for microvessel visualization are limited by insufficient penetration and instability of endothelial immunolabels, inadequate vascular perfusion by the high-viscosity polymers used for vascular casting, and destruction of tissue stroma during the processing required for scanning electron microscopy. The aim of this study was to develop whole-mount tissue processing methods for 3D in situ visualization of the microvasculature that were also compatible with supplementary labeling for other structures of interest in the tissue microenvironment. Here, we present techniques that allow imaging of the microvasculature by confocal microscopy, to depths of up to 1500 mum below the specimen surface. Our approach includes labeling luminal surfaces of endothelial cells by i.v. injection of fluorescently conjugated lectin and filling the microvasculature with carbon or fluorescent nanoparticles/Mercox, followed by optical clearing of thick tissue sections to reduce light scatter and permit 3D visualization of microvessel morphology deep into the sample. Notably, tissue stroma is preserved, allowing simultaneous labeling of other structures by immunohistochemistry or nuclear dyes. Results are presented for various murine tissues including fat, muscle, heart and brain under conditions of normal health, as well as in the setting of a glioma model growing in the subcutaneous space or orthotopically in the brain parenchyma.

Descending facilitation from the rostral ventromedial medulla maintains nerve injury-induced central sensitization

Nerve injury can produce hypersensitivity to noxious and normally innocuous stimulation. Injury-induced central (i.e. spinal) sensitization is thought to arise from enhanced afferent input to the spinal cord and to be critical for expression of behavioral hypersensitivity. Descending facilitatory influences from the rostral ventromedial medulla have been suggested to also be critical for the maintenance, though not the initiation, of experimental neuropathic pain. The possibility that descending facilitation from the rostral ventromedial medulla is required for the maintenance of central sensitization was examined by determining whether ablation of mu-opioid receptor-expressing cells within the rostral ventromedial medulla prevented the enhanced expression of repetitive touch-evoked FOS within the spinal cord of animals with spinal nerve ligation injury as well as nerve injury-induced behavioral hypersensitivity. Rats received a single microinjection of vehicle, saporin, dermorphin or dermorphin-saporin into the rostral ventromedial medulla and 28 days later, underwent either sham or spinal nerve ligation procedures. Animals receiving rostral ventromedial medulla pretreatment with vehicle, dermorphin or saporin that were subjected to spinal nerve ligation demonstrated both thermal and tactile hypersensitivity, and showed significantly increased expression of touch-evoked FOS in the dorsal horn ipsilateral to nerve injury compared with sham-operated controls at days 3, 5 or 10 post-spinal nerve ligation. In contrast, nerve-injured animals pretreated with dermorphin-saporin showed enhanced behaviors and touch-evoked FOS expression in the spinal dorsal horn at day 3, but not days 5 and 10, post-spinal nerve ligation when compared with sham-operated controls. These results indicate the presence of nerve injury-induced behavioral hypersensitivity associated with nerve injury-induced central sensitization. Further, the results demonstrate the novel concept that once initiated, maintenance of nerve injury-induced central sensitization in the spinal dorsal horn requires descending pain facilitation mechanisms arising from the rostral ventromedial medulla.