Data set describing the in vitro biological activity of JMV2009, a novel silylated neurotensin(8-13) analog.

Neurotensin (NT) is a tridecapeptide displaying interesting antinociceptive properties through its action on its receptors, NTS1 and NTS2. Neurotensin-like compounds have been shown to exert better antinociceptive properties than morphine at equimolar doses. In this article, we characterized the molecular effects of a novel neurotensin (8-13) (NT(8-13)) analog containing an unnatural amino acid. This compound, named JMV2009, displays a Silaproline in position 10 in replacement of a proline in the native NT(8-13). We first examined the binding affinities of this novel NT(8-13) derivative at both NTS1 and NTS2 receptor sites by performing competitive displacement of iodinated NT on purified cell membranes. Then, we evaluated the ability of JMV2009 to activate NTS1-related G proteins as well as to promote the recruitment of ß-arrestins 1 and 2 by using BRET-based cellular assays in live cells. We next assessed its ability to induce p42/p44 MAPK phosphorylation and NT receptors internalization using western blot and cell-surface ELISA, respectively. Finally, we determined the in vitro plasma stability of this NT derivative. This article is associated with the original article "Pain relief devoid of opioid side effects following central action of a silylated neurotensin analog" published in European Journal of Pharmacology[1]. The reader is directed to the associated article for results interpretation, comments, and discussion.

Pain relief devoid of opioid side effects following central action of a silylated neurotensin analog.

Neurotensin (NT) exerts naloxone-insensitive antinociceptive action through its binding to both NTS1 and NTS2 receptors and NT analogs provide stronger pain relief than morphine on a molecular basis. Here, we examined the analgesic/adverse effect profile of a new NT(8-13) derivative denoted JMV2009, in which the Pro10 residue was substituted by a silicon-containing unnatural amino acid silaproline. We first report the synthesis and in vitro characterization (receptor-binding affinity, functional activity and stability) of JMV2009. We next examined its analgesic activity in a battery of acute, tonic and chronic pain models. We finally evaluated its ability to induce adverse effects associated with chronic opioid use, such as constipation and analgesic tolerance or related to NTS1 activation, like hypothermia. In in vitro assays, JMV2009 exhibited high binding affinity for both NTS1 and NTS2, improved proteolytic resistance as well as agonistic activities similar to NT, inducing sustained activation of p42/p44 MAPK and receptor internalization. Intrathecal injection of JMV2009 produced dose-dependent antinociceptive responses in the tail-flick test and almost completely abolished the nociceptive-related behaviors induced by chemical somatic and visceral noxious stimuli. Likewise, increasing doses of JMV2009 significantly reduced tactile allodynia and weight bearing deficits in nerve-injured rats. Importantly, repeated agonist treatment did not result in the development of analgesic tolerance. Furthermore, JMV2009 did not cause constipation and was ineffective in inducing hypothermia. These findings suggest that NT drugs can act as an effective opioid-free medication for the management of pain or can serve as adjuvant analgesics to reduce the opioid adverse effects.

Brain irradiation leads to persistent neuroinflammation and long-term neurocognitive dysfunction in a region-specific manner.

Long-term cognitive deficits are observed after treatment of brain tumors or metastases by radiotherapy. Treatment optimization thus requires a better understanding of the effects of radiotherapy on specific brain regions, according to their sensitivity and interconnectivity. In the present study, behavioral tests supported by immunohistology and magnetic resonance imaging provided a consistent picture of the persistent neurocognitive decline and neuroinflammation after the onset of irradiation-induced necrosis in the right primary somatosensory cortex of Fischer rats. Necrosis surrounded by neovascularization was first detected 54 days after irradiation and then spread to 110 days in the primary motor cortex, primary somatosensory region, striatum and right ventricle, resulting in fiber bundle disruption and demyelination in the corpus callosum of the right hemisphere. These structural damages translated into selective behavioral changes including spatial memory loss, disinhibition of anxiety-like behaviors, hyperactivity and pain hypersensitivity, but no significant alteration in motor coordination and grip strength abilities. Concomitantly, activated microglia and reactive astrocytes, accompanied by infiltration of leukocytes (CD45+) and T-cells (CD3+) cooperated to shape the neuroinflammation response. Overall, our study suggests that the slow and gradual onset of cellular damage would allow adaptation in brain regions that are susceptible to neuronal plasticity; while other cerebral structures that do not have this capacity would be more affected. The planning of radiotherapy, adjusted to the sensitivity and adaptability of brain structures, could therefore preserve certain neurocognitive functions; while higher doses of radiation could be delivered to brain areas that can better adapt to this treatment. In addition, strategies to block early post-radiation events need to be explored to prevent the development of long-term cognitive dysfunction.

Publisher Correction: Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Dichotomic effects of clinically used drugs on tumor growth, bone remodeling and pain management.

Improvements in the survival of breast cancer patients have led to the emergence of bone health and pain management as key aspects of patient's quality of life. Here, we used a female rat MRMT-1 model of breast cancer-induced bone pain to compare the effects of three drugs used clinically morphine, nabilone and zoledronate on tumor progression, bone remodeling and pain relief. We found that chronic morphine reduced the mechanical hypersensitivity induced by the proliferation of the luminal B aggressive breast cancer cells in the tumor-bearing femur and prevented spinal neuronal and astrocyte activation. Using MTT cell viability assay and MRI coupled to 18FDG PET imaging followed by ex vivo 3D µCT, we further demonstrated that morphine did not directly exert tumor growth promoting or inhibiting effects on MRMT-1 cancer cells but induced detrimental effects on bone healing by disturbing the balance between bone formation and breakdown. In sharp contrast, both the FDA-approved bisphosphonate zoledronate and the synthetic cannabinoid nabilone prescribed as antiemetics to patients receiving chemotherapy were effective in limiting the osteolytic bone destruction, thus preserving the bone architecture. The protective effect of nabilone on bone metabolism was further accompanied by a direct inhibition of tumor growth. As opposed to zoledronate, nabilone was however not able to manage bone tumor-induced pain and reactive gliosis. Altogether, our results revealed that morphine, nabilone and zoledronate exert disparate effects on tumor growth, bone metabolism and pain control. These findings also support the use of nabilone as an adjuvant therapy for bone metastases.

Combination of high-fat/high-fructose diet and low-dose streptozotocin to model long-term type-2 diabetes complications.

The epidemic of type 2 diabetes mellitus (T2DM) is fueled by added fructose consumption. Here, we thus combined high-fat/high-fructose diet, with multiple low-dose injections of streptozotocin (HF/HF/Stz) to emulate the long-term complications of T2DM. HF/HF/Stz rats, monitored over 56 weeks, exhibited metabolic dysfunctions associated with the different stages of the T2DM disease progression in humans: an early prediabetic phase characterized by an hyperinsulinemic period with modest dysglycemia, followed by a late stage of T2DM with frank hyperglycemia, normalization of insulinemia, marked dyslipidemia, hepatic fibrosis and pancreatic ß-cell failure. Histopathological analyses combined to [18F]-FDG PET imaging further demonstrated the presence of several end-organ long-term complications, including reduction in myocardial glucose utilization, renal dysfunction as well as microvascular neuropathy and retinopathy. We also provide for the first time a comprehensive µ-PET whole brain imaging of the changes in glucose metabolic activity within discrete cerebral regions in HF/HF/Stz diabetic rats. Altogether, we developed and characterized a unique non-genetic preclinical model of T2DM adapted to the current diet and lifestyle that recapitulates the major metabolic features of the disease progression, from insulin resistance to pancreatic ß-cell dysfunction, and closely mimicking the target-organ damage occurring in type 2 diabetic patients at advanced stages.