LY 379268

LY 379268 is a highly selective group II mGlu receptor agonist with EC50 value of 2.69 and 4.48 nM for hmGlu2 and hmGlu3, respectively [1].
mGluRs is a type of glutamate receptor that is being considered as targets for the therapeutic intervention in neurodegenerative disorders. Activation of Group II mGluRs can protect cultured neurones against excitotoxic damage by inhibiting glutamate release [1].
In the CA1 hippocampal cells, LY379268 reduced the ischemia-induced hyperactivity and provided protection after 5-min bilateral carotid artery occlusion (BCAO). Furthermore, before 5-min BCAO, 24- or 48-h pretreatment with LY379268 educed the damage to CA1 hippocampal neurons in a gerbil model [2].
In the gerbil bilateral occlusion of the carotid artery, LY379268 prevented the loss of CA1 hippocampal neurones. Also, LY379268 decreased the BCAO-induced increase in TUNEL positive cells. In the rat model, LY379268 didn’t affect the size of the infarct following middle cerebral artery occlusion (MCAO) [1].
References:
[1]. Bond A, Ragumoorthy N, Monn JA, et al. LY379268, a potent and selective Group II metabotropic glutamate receptor agonist, is neuroprotective in gerbil global, but not focal, cerebral ischaemia. Neurosci Lett, 1999, 273(3): 191-194.
[2]. Bond A, Jones NM, Hicks CA, et al. Neuroprotective effects of LY379268, a selective mGlu2/3 receptor agonist: investigations into possible mechanism of action in vivo. J Pharmacol Exp Ther, 2000, 294(3): 800-809.

Clinical and immunohistochemical performance of lyophilized platelet-rich fibrin (Ly-PRF) on tissue regeneration.[Pubmed:28192870]

Clin Implant Dent Relat Res. 2017 Jun;19(3):466-477.

BACKGROUND: Platelet-rich fibrin (PRF) has been widely used in oral implantology and other fields, but benefits of the fresh PRF (FPRF (fresh platelet-rich fibrin)) were consequently limited because of its short-term application. Thus, a protocol for the combination of PRF and lyophilization comes up in the present study to address the issue of PRF storage and delayed clinical application, which has little been reported in this field at home and abroad by now. PURPOSE: The aim of the present study was to evaluate the applicability of lyophilized platelet-rich fibrin (Ly-PRF) used as the scaffold material for craniofacial tissue regeneration and to compare its biochemical properties with commonly used fresh PRF. MATERIALS AND METHODS: Two volunteers with both genders were selected as the source of PRF and Ly-PRF samples. Macro- and micro-scopic appearance evaluation as well as immunohistochemical comparison were performed on PRF samples before and after freeze-drying at -196 degrees C. The second experimental phase was to observe clinical performance when fresh and lyophilized PRF were applied in guided bone regeneration (GBR) operations in 39 patients losing teeth in the anterior maxillary region who required an oral implantation followed by labial bone grafting. RESULTS: The conventional histological and transmission electron microscopy images showed the microstructure of Ly-PRF, which resembled a mesh containing apparently irregularly shaped platelets with less alpha-granule than fresh PRF in micro and a translucent membrane with less elasticity than fresh PRF in macro. Simultaneous immunohistological staining results showed positive expression of PDGF-BB, IL-1, IL-4, TNF, TGF-beta1 in both fresh and lyophilized PRF, while the expression of PDGF-BB, IL-1, TNF, TGF-beta1 has no statistical difference between them (P > .05) but that of IL-4 in Ly-PRF is statistically higher than in fresh PRF (P < .05). When applied in GBR operations, there were no significant differences between Ly-PRF and FPRF in factors of histological and clinical evaluations (i.e., color, swelling, bleeding of the mucosa, pain leveland, and remodeling of hard tissue) performed 3 days, 7 days, and 4 months after the surgery (P > .05). CONCLUSIONS: This study strongly supports that lyophilization at -196 degrees C does not largely influence the expression of bioactive factors, the microstructure of fibrinogen or the clinical effects of PRF.

Expansion of CD11b(+)Ly-6C(+) myeloid-derived suppressor cells (MDSCs) driven by galectin-9 attenuates CVB3-induced myocarditis.[Pubmed:28110209]

Mol Immunol. 2017 Mar;83:62-71.

Galectin-9 is known to play a role in the modulation of innate and adaptive immunity to ameliorate CVB3-induced myocarditis. In the present study, we found that galectin-9 induced the expansion of CD11b(+)Ly-6C(+) myeloid-derived suppressor cells (MDSCs) in the heart from CVB3-infected mice. Adoptive transfer of CD11b(+)Ly-6C(+) MDSCs significantly alleviated myocarditis accompanied by increased Th2 and Treg frequency and anti-inflammatory cytokines expression in the heart tissue. Moreover, Ly6C(+) MDSCs, but not Ly6G(+) cells, expressed Arg-1 and NOS2, and suppressed CD4(+) T cell proliferation in vitro in an Arg-1-dependent mechanism; an event that was reversed with treatment of either an Arg-1 inhibitor or addition of excess l-arginine. Furthermore, Ly6C(+) MDSCs co-expressed higher levels of F4/80, Tim-3, and IL-4Ralpha, and had the plasticity to up-regulate NOS2 or Arg-1 in response to IFN-gamma or IL-4 treatment. The present results indicate that galectin-9 expands CD11b(+)Ly-6C(+) MDSCs to ameliorate CVB3-induced myocarditis.

Assessment of roles for the Rho-specific guanine nucleotide dissociation inhibitor Ly-GDI in platelet function: a spatial systems approach.[Pubmed:28148498]

Am J Physiol Cell Physiol. 2017 Apr 1;312(4):C527-C536.

On activation at sites of vascular injury, platelets undergo morphological alterations essential to hemostasis via cytoskeletal reorganizations driven by the Rho GTPases Rac1, Cdc42, and RhoA. Here we investigate roles for Rho-specific guanine nucleotide dissociation inhibitor proteins (RhoGDIs) in platelet function. We find that platelets express two RhoGDI family members, RhoGDI and Ly-GDI. Whereas RhoGDI localizes throughout platelets in a granule-like manner, Ly-GDI shows an asymmetric, polarized localization that largely overlaps with Rac1 and Cdc42 as well as microtubules and protein kinase C (PKC) in platelets adherent to fibrinogen. Antibody interference and platelet spreading experiments suggest a specific role for Ly-GDI in platelet function. Intracellular signaling studies based on interactome and pathways analyses also support a regulatory role for Ly-GDI, which is phosphorylated at PKC substrate motifs in a PKC-dependent manner in response to the platelet collagen receptor glycoprotein (GP) VI-specific agonist collagen-related peptide. Additionally, PKC inhibition diffuses the polarized organization of Ly-GDI in spread platelets relative to its colocalization with Rac1 and Cdc42. Together, our results suggest a role for Ly-GDI in the localized regulation of Rho GTPases in platelets and hypothesize a link between the PKC and Rho GTPase signaling systems in platelet function.

Short-term dabigatran interruption before cardiac rhythm device implantation: multi-centre experience from the RE-LY trial.[Pubmed:28339794]

Europace. 2017 Oct 1;19(10):1630-1636.

Aims: Cardiac implantable electronic device (CIED) surgery is commonly performed in patients with atrial fibrillation (AF). The current analysis was undertaken to compare peri-operative anticoagulation management, bleeding, and thrombotic events in AF patients treated with dabigatran vs. warfarin. Methods and results: This study included 611 patients treated with dabigatran vs. warfarin who underwent CIED surgery during the RE-LY trial. Among 201 warfarin-treated patients, warfarin was interrupted a median of 144 (inter-quartile range, IQR: 120-216) h, and 37 (18.4%) patients underwent heparin bridging. In dabigatran-treated patients (216 on 110 mg bid and 194 on 150 mg bid), the duration of dabigatran interruption was a median of 96 (IQR: 61-158) h. Pocket hematomas occurred in 9 (2.20%) patients on dabigatran and 8 (3.98%) patients on warfarin (P = 0.218). The occurrence of pocket hematomas was lower with dabigatran compared with warfarin with heparin bridging (RD: -8.62%, 95% CI: -24.15 to - 0.51%, P = 0.034) but not when compared with warfarin with no bridging (P = 0.880). Ischemic stroke occurred in 2 (0.3%) patients; one in the warfarin group (without bridging) and one in the dabigatran 150 mg bid group (P = 0.735). Conclusion: In patients treated with dabigatran undergoing CIED surgery, interruption of dabigatran is associated with similar or lower incidence of pocket hematoma, when compared with warfarin interruption without or with heparin bridging, respectively. Whether uninterrupted dabigatran can reduce pocket hematoma or ischemic stroke remains to be evaluated.

(2S,1'S,2'S,3'R)-2-(2'-carboxy-3'-methylcyclopropyl) glycine is a potent and selective metabotropic group 2 receptor agonist with anxiolytic properties.[Pubmed:12166935]

J Med Chem. 2002 Aug 15;45(17):3619-29.

The asymmetric synthesis and biological activity of (2S,1'S,2'S,3'R)-2-(2'-carboxy-3'-methylcyclopropyl) glycine 7 and its epimer at the C3' center 6 are described. Compound 7 is a highly potent and selective agonist for group 2 metabotropric glutamate receptors (mGluRs). It is also systemically 4 orders of magnitude more active in the fear-potentiated startle model of anxiety in rats than the rigid constrained bicyclic system LY354740. Therefore, we have shown that high molecular complexity of conformationally constrained bicyclic systems is not a requirement to achieve highly selective and potent group 2 mGluRs agonists.

Neuroprotective effects of LY379268, a selective mGlu2/3 receptor agonist: investigations into possible mechanism of action in vivo.[Pubmed:10945827]

J Pharmacol Exp Ther. 2000 Sep;294(3):800-9.

The mechanisms underlying the neuroprotective effects of the group II metabotropic glutamate receptor (mGluR) agonist LY379268 were investigated in a gerbil model of global ischemia. LY379268 (10 mg/kg i.p.) 30 or 60 min after 5-min bilateral carotid artery occlusion (BCAO) attenuated the ischemia-induced hyperactivity and provided protection in the CA1 hippocampal cells. This neuroprotective effect was maintained (P <.001) when histological analysis was performed 14 and 28 days after BCAO. Furthermore, 24- or 48-h pretreatment with LY379268, 10 mg/kg i.p., before 5-min BCAO markedly reduced (P <.001 and P <.05, respectively) the damage to CA1 hippocampal neurons. This result is consistent with the induction of neuroprotective factors or a very long brain half-life. To study the possible induction of neuroprotective factors as contributing to this action of LY379268, brains were examined for expression of neurotrophic factors. Results indicated that LY379268 (10 mg/kg i.p.) failed to alter the expression of transforming growth factor-beta, brain-derived neurotrophic factor, nerve growth factor, and basic fibroblast growth factor in the hippocampal regions of brains taken from gerbils sacrificed at 6, 24, 72, and 120 h postinjection. The new group II mGlu antagonist, LY341495, administered 1 h before 5-min BCAO, attenuated the neuroprotective effect of LY379268 administered 24 h before 5-min BCAO. Complementary pharmacokinetic studies showed that a significant receptor-active concentration persisted in the brain 24 h after LY379268 10 mg/kg i.p. We conclude that group II mGluR occupancy, rather than induction of neuroprotective factors, explains the long-lasting neuroprotective effect of LY379268 in the gerbil model of global ischemia.

LY379268, a potent and selective Group II metabotropic glutamate receptor agonist, is neuroprotective in gerbil global, but not focal, cerebral ischaemia.[Pubmed:10515191]

Neurosci Lett. 1999 Oct 8;273(3):191-4.

The neuroprotective effects of a selective Group II metabotropic glutamate receptor (mGluR) agonist, LY379268, have been evaluated against global and focal cerebral ischaemia. Loss of CA1 hippocampal neurones following 5 min bilateral occlusion of the carotid artery (BCAO) in the gerbil was almost completely prevented by LY379268 (10 mg/kg, i.p.) given 30 min post-occlusion (P < 0.001); 10 mg/kg 1 h after and 20 mg/kg 2 h after BCAO also produced significant neuroprotection (P < 0.05). Similarly the BCAO-induced increase in TUNEL positive cells at 5 days post-occlusion was reduced by LY379268. By contrast the size of the infarct following middle cerebral artery occlusion (MCAO) induced by endothelin-1 infusion in the rat was unaffected by either 10 or 20 mg/kg i.p. of LY379268. This contrast between the results from these two animal models with LY379268, agrees with previous data on a less potent but similarly selective mGluR2/3 agonist, LY354740. It further suggests that mGluR Group II agonists are likely to have more utility in global, than in focal, cerebral ischaemia.