Toward discovering a novel family of peptides targeting neuroinflammatory states of brain microglia and astrocytes

Microglia are immune-derived cells critical to the development and healthy function of the brain and spinal cord, yet are implicated in the active pathology of many neuropsychiatric disorders. A range of functional phenotypes associated with the healthy brain or disease states has been suggested from in vivo work and were modeled in vitro as surveying, reactive, and primed sub-types of primary rat microglia and mixed microglia/astrocytes. It was hypothesized that the biomolecular profile of these cells undergoes a phenotypical change as well, and these functional phenotypes were explored for potential novel peptide binders using a custom 7 amino acid-presenting M13 phage library (SX7) to identify unique peptides that bind differentially to these respective cell types. Surveying glia were untreated, reactive were induced with a lipopolysaccharide treatment, recovery was modeled with a potent anti-inflammatory treatment dexamethasone, and priming was determined by subsequently challenging the cells with interferon gamma. Microglial function was profiled by determining the secretion of cytokines and nitric oxide, and expression of inducible nitric oxide synthase. After incubation with the SX7 phage library, populations of SX7-positive microglia and/or astrocytes were collected using fluorescence-activated cell sorting, SX7 phage was amplified in Escherichia coli culture, and phage DNA was sequenced via next-generation sequencing. Binding validation was done with synthesized peptides via in-cell westerns. Fifty-eight unique peptides were discovered, and their potential functions were assessed using a basic local alignment search tool. Peptides potentially originated from proteins ranging in function from a variety of supportive glial roles, including synapse support and pruning, to inflammatory incitement including cytokine and interleukin activation, and potential regulation in neurodegenerative and neuropsychiatric disorders.

Donor kidney recovery methods and the incidence of lymphatic complications in kidney transplant recipients

BACKGROUND

Lymphatic leak and lymphocele are well-known complications after kidney transplantation.

OBJECTIVE

To determine the incidence of lymphatic complications in recipients of living donor kidneys.

METHODS

Among 642 kidney transplants performed between 1999 and 2007, the incidence of lymphatic complications was retrospectively analyzed in recipients of living donor kidneys procured by laparoscopic nephrectomy (LP, n=218) or by open nephrectomy (OP, n=127) and deceased donor kidneys (DD, n=297). A Jackson-Pratt drain was placed in the retroperitoneal space in all recipients and was maintained until the output became less than 30 mL/day.

RESULTS

Although the incidence of symptomatic lymphocele, which required therapeutic intervention, was comparable in all groups, the duration of mean±SD drain placement was significantly longer in the LP group-8.6±2.7 days compared to 5.6±1.2 days in the OP group and 5.4±0.7 days in the DD group (p<0.001). Higher output of lymphatic drainage in recipients of LP kidneys could lead to a higher incidence of lymphocele if wound drainage is not provided.

CONCLUSION

More meticulous back table preparation may be required in LP kidneys to decrease lymphatic complications after kidney transplantation. These observations also support the suggestion that the major source of persistent lymphatic drainage following renal transplantation is severed lymphatics of the allograft rather than those of the recipient's iliac space.

Impact of donor kidney recovery method on lymphatic complications in kidney transplantation

INTRODUCTION

Prolonged lymphatic drainage and lymphocele are undesirable complications following kidney transplantation. We evaluated the impact of kidney recovery methods (deceased donor vs laparoscopic nephrectomy) on the lymphatic complications of the kidney transplant recipients.

METHOD

The incidence of lymphatic complications was retrospectively analyzed in recipients of deceased donor kidneys (DD, n = 62) versus laparoscopically procured kidneys from living donors (LP, n = 61). A drain was placed in the retroperitoneal space in all recipients. The drain was maintained until the output became less than 30 mL/d with no evidence of fluid collection by ultrasound examination.

RESULTS

There was no statistically significant difference in the patient demographics (age, gender, and original disease and procedure time) between two groups. The incidence of lymphocele that required therapeutic intervention was comparable in both groups (3.2%). However, the duration of drain placement was significantly longer in the LP group than in the DD group, 8.6 +/- 2.5 days versus 5.4 +/- 2.5 day, respectively (P < .05).

CONCLUSION

The recipients of laparoscopically removed kidneys had a higher incidence of prolonged lymphatic leakage. More meticulous back table preparation may be required in LP kidneys to prevent prolonged lymphatic drainage after kidney transplantation. These observations may indicate that the major source of persistent lymphatic leakage is lymphatics of the allograft rather than severed recipient lymphatics.

Bcr-abl-positive cells secrete angiogenic factors including matrix metalloproteinases and stimulate angiogenesis in vivo in Matrigel implants

To further elucidate the role of angiogenesis in the pathogenesis of chronic myelogenous leukemia (CML) we evaluated the effects of the bcr-abl translocation on the secretion of the angiogenic factors VEGF, FGF-2, HGF, IL-8 and matrix metalloproteinases (MMPs) as well as on the angiogenic potential in vivo of bcr-abl+ cells. First, we examined murine FL5.12 cells transfected with the bcr-abl constructs p185, p210 and p230 and found that the transfected cells secreted as much as four-fold more VEGF (p185 > p210 >p230) than wild-type (wt) cells, as well as MMP-9 and MMP-2. When Matrigel fragments containing these bcr-abl+ cells were implanted subcutaneously in SCID or Balb-C mice they became significantly more vascularized and hemoglobinized than implants containing normal or wt cells (p185 > p210 > p230). Similarly, we found that myeloblasts expanded from bone marrow (BM) CD34+ cells derived from Philadelphia-positive CML patients secreted up to 10 times more VEGF, FGF-2, HGF and IL-8 compared to myeloblasts derived from normal donors' BM CD34+ cells and that BM mononuclear cells (MNC) isolated from CML patients induced vascularization of Matrigel implants in mice. Moreover, we found that peripheral blood MNC expressed MMP-2 and membrane-type (MT)1-MMP in about 50% of CML patients studied, and MMP-9 in all of them. Furthermore, VEGF stimulated the secretion of MMP-9 in these primary CML cells. We conclude that stimulation of angiogenesis by angiogenic factors, including MMPs, could play an important role in the pathogenesis of CML, suggesting that therapies targeting the newly formed endothelium could be developed for CML.