CD38-cells, and lymphocytes, but not mature myeloid cells. Similarly, mRNA for the AT1a receptor was expressed on human stromal cell clones, offering further support to the hypothesis that AII acts partially through the mesenchymal compartment of the bone marrow. These data suggest that AII may be a factor which stimulates the proliferation of hematopoietic progenitors.
Sjögren’s syndrome (SjS) is a chronic autoimmune disease characterized initially by lymphocytic infiltration and destruction of exocrine glands, followed by systemic organ damage and B-cell lymphoma. Conventional treatment is based on management of symptoms and there is a shortage of therapies that address the underlying causes of inflammation at source exocrine tissue. The aim of this study was to test a novel protein polymer-based platform consisting of diblock copolymers composed from Elastin-like Polypeptides (ELPs) fused with FKBP12, to deliver a potent immunosuppressant with dose-limiting toxicity, rapamycin (Rapa) also known as Sirolimus, and evaluate its effects on the inflamed lacrimal gland (LG) of non-obese diabetic mouse (NOD), a classic mouse model of SjS. Both soluble and diblock copolymer ELPs were fused to FKBP12 and characterized with respect to purity, hydrodynamic radii, drug entrapment and release. Both formulations showed successful association with Rapa; however, the nanoparticle formulation, FSI, released drug with nearly a 5 fold longer terminal half-life of 62.5h. The strong interaction of FSI nanoparticles with Rapa was confirmed in vivo by a shift in the monoexponential pharmacokinetic profile for free drug to a biexponential profile for the nanoparticle formulation. When acutely administered by injection into NOD mice via the tail vein, this FSI formulation significantly suppressed lymphocytic infiltration in the LG relative to the control group while reducing toxicity. There was also a significant effect on inflammatory and mammalian target of Rapamycin (mTOR) pathway genes in the LG and surprisingly, our nanoparticle formulation was significantly better at decreasing a proposed tear biomarker of SjS, cathepsin S (CATS) compared to free drug. These findings suggest that FSI is a promising tool for delivering Rapa for treatment of SjS in a murine model and may be further explored to meet the unmet medical challenge of SjS.
Rationale
We propose renin angiotensin system (RAS) peptides are critical in wound reparative processes such as in acute respiratory distress syndrome (ARDS). Their role in predicting clinical outcomes in ARDS has been unexplored; thus, we used a targeted metabolomics approach to investigate them as potential predictors of outcomes.
Methods
Thirty-nine ARDS patients were enrolled within 24 hours of ARDS diagnosis. Plasma RAS peptide levels were quantified at study entry and 24, 48 and 72 hours using a liquid chromatography-mass spectrometry based metabolomics assay. RAS peptide concentrations were compared between survivors and non-survivors, and were correlated with clinical and pulmonary measures.
Measurements and main results
Angiotensin I (Ang-I or A(1–10)) levels were significantly higher in non-survivors at study entry and 72 hours. ARDS survival was associated with lower A(1–10) concentration (OR 0.36, 95% CI 0.18–0.72, p = 0.004) but higher A(1–9) concentration (OR 2.24, 95% CI 1.15–4.39, p = 0.018), a biologically active metabolite of A(1–10) and an agonist of angiotensin II receptor type 2. Survivors had significantly higher median A(1–9)/A(1–10) and A(1–7)/A(1–10) ratios than the non-survivors (p = 0.001). Increased A(1–9)/A(1–10) ratio suggests that angiotensin converting enzyme II (ACE2) activity is higher in patients who survived their ARDS insult while an increase in A(1–7)/A(1–10) ratio suggests that ACE activity is also higher in survivors.
Conclusion
A(1–10) accumulation and reduced A(1–9) concentration in the non-survivor group suggest that ACE2 activities may be reduced in patients succumbing to ARDS. Plasma levels of both A(1–10) and A(1–9) and their ratio may serve as useful biomarkers for prognosis in ARDS patients.
The sodium channel NaV1.7 is a master regulator of nociceptive neuronal firing. Mutations in this channel can result in painful conditions as well as produce insensitivity to pain. Despite being recognized as a "poster child" for nociceptive signaling and human pain, targeting NaV1.7 has not yet produced a clinical drug. Recent work has illuminated the NaV1.7 interactome, offering insights into the regulation of these channels and identifying potentially new druggable targets. Amongst the regulators of NaV1.7 is the cytosolic collapsin response mediator protein 2 (CRMP2). CRMP2, modified at Lysine 374 (K374) by addition of a small ubiquitin-like modifier (SUMO), bound NaV1.7 to regulate its membrane localization and function. Corollary to this, preventing CRMP2 SUMOylation was sufficient to reverse mechanical allodynia in rats with neuropathic pain. Notably, loss of CRMP2 SUMOylation did not compromise other innate functions of CRMP2. To further elucidate the in vivo role of CRMP2 SUMOylation in pain, we generated CRMP2 K374A knock-in (CRMP2 K374A/K374A ) mice in which Lys374 was replaced with Ala. CRMP2 K374A/K374A mice had reduced NaV1.7 membrane localization and function in female, but not male, sensory neurons. Behavioral appraisal of CRMP2 K374A/K374A mice demonstrated no changes in depressive or repetitive, compulsive-like behaviors, and a decrease in noxious thermal sensitivity. No changes were observed in CRMP2 K374A/K374A mice to inflammatory, acute, or visceral pain. In contrast, in a neuropathic model, CRMP2 K374A/K374A mice failed to develop persistent mechanical allodynia. Our study suggests that CRMP2 SUMOylation-dependent control of peripheral NaV1.7 is a hallmark of chronic, but not physiological, neuropathic pain.
These findings suggest that these peptides utilize distinct receptors in the stimulation of hematopoietic recovery. In summary, systemic administration of angiotensin peptides led to an acceleration in hematopoietic recovery after irradiation. These peptides act to stimulate the formation of bone marrow progenitors, thereby facilitating recovery after myelosuppressive irradiation.
Recent studies have shown that angiotensin peptides accelerate dermal repair. Histological observation of samples taken at the termination of studies showed that the wounds treated with peptides were mature and organized by day 25 after full thickness excision in diabetic mice. However, the mechanisms by which this acceleration occurs has not been determined. In the experiments described here, the effect of angiotensin peptides (AII, A(1-7) and NorLeu (3)-A(1-7) on the quality of the healing wound was evaluated histologically. Administration of the peptides accelerated collagen deposition, re-epithelialization and new blood vessels formation. By day 4, the percentage of the wound with collagen increased two- to six-fold depending upon the peptide. The increase by angiotensin peptides continued throughout the experimental period. On days 4 and 7 9 (only) after injury, exposure to angiotensin peptides increased the number of blood vessels at wound site two-to three-fold. Finally, the percentage of the wound site covered with new epithelium increased after administration of angiotensin peptides. Re-epithelialization was observed as early as day 4 in wounds treated ith angiotensin peptides. The increase was greater at later time points (up to 8-fold ar day 14 with NorLeu(3)-A(1-7) had an increase in neutrophils and macrophages on day 4 after wounding. Overall, administration of these peptides resulted in a healing site that was more mature, including reorganization of the collagen into a basket-weave appearance. Further, these studies confirm the superiority of NorLeu(3)-A(1-7) to AII and A(1-7) in wound healing evaluated at a microscopic level.
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