A peptide-neurotensin conjugate that crosses the blood-brain barrier induces pharmacological hypothermia associated with anticonvulsant, neuroprotective, and anti-inflammatory properties following status epilepticus in mice.
VH-N412 shows potential for inducing neuroprotective hypothermia in a mouse model, but further research is needed to assess its clinical relevance.
Where it sits
this study against the rest of the abs-201 corpusSummary and findings
The study evaluated a peptide-neurotensin conjugate, VH-N412, in a mouse model of kainate-induced status epilepticus. VH-N412 induced pharmacological hypothermia and exhibited anticonvulsant, neuroprotective, and anti-inflammatory effects. The conjugate improved brain distribution and stability compared to neurotensin alone.
Abstract
Preclinical and clinical studies show that mild to moderate hypothermia is neuroprotective in sudden cardiac arrest, ischemic stroke, perinatal hypoxia/ischemia, traumatic brain injury, and seizures. Induction of hypothermia largely involves physical cooling therapies, which induce several clinical complications, while some molecules have shown to be efficient in pharmacologically induced hypothermia (PIH). Neurotensin (NT), a 13 amino acid neuropeptide that regulates body temperature, interacts with various receptors to mediate its peripheral and central effects. NT induces PIH when administered intracerebrally. However, these effects are not observed if NT is administered peripherally, due to its rapid degradation and poor passage of the blood-brain barrier (BBB). We conjugated NT to peptides that bind the low-density lipoprotein receptor (LDLR) to generate 'vectorized' forms of NT with enhanced BBB permeability. We evaluated their effects in epileptic conditions following peripheral administration. One of these conjugates, VH-N412, displayed improved stability, binding potential to both the LDLR and NTSR-1, rodent/human cross-reactivity and improved brain distribution. In a mouse model of kainate (KA)-induced status epilepticus (SE), VH-N412 elicited rapid hypothermia associated with anticonvulsant effects, potent neuroprotection, and reduced hippocampal inflammation. VH-N412 also reduced sprouting of the dentate gyrus mossy fibers and preserved learning and memory skills in the treated mice. In cultured hippocampal neurons, VH-N412 displayed temperature-independent neuroprotective properties. To the best of our knowledge, this is the first report describing the successful treatment of SE with PIH. In all, our results show that vectorized NT may elicit different neuroprotection mechanisms mediated by hypothermia and/or by intrinsic neuroprotective properties.
Background
The study addresses the challenge of inducing neuroprotective hypothermia in conditions such as seizures and traumatic brain injury. Traditional physical cooling methods have limitations, and pharmacological approaches are being explored. Neurotensin is known for its thermoregulatory effects but has limited peripheral efficacy due to poor blood-brain barrier permeability. This study explores a novel conjugate to enhance neurotensin's therapeutic potential.
Methods
The researchers conjugated neurotensin to peptides targeting the low-density lipoprotein receptor to improve blood-brain barrier permeability. The conjugate, VH-N412, was tested in a mouse model of kainate-induced status epilepticus. Outcomes included hypothermia induction, anticonvulsant effects, neuroprotection, and inflammation reduction. Additional in vitro tests were conducted on cultured hippocampal neurons.
Results
VH-N412 induced rapid hypothermia in the mouse model, accompanied by anticonvulsant and neuroprotective effects. It reduced hippocampal inflammation and preserved cognitive functions. In vitro, VH-N412 showed neuroprotective properties independent of temperature changes. These findings suggest enhanced brain distribution and efficacy compared to neurotensin alone.
Interpretation
The results indicate that VH-N412 may offer a novel approach to inducing pharmacological hypothermia with additional neuroprotective benefits. While promising, the findings are limited to preclinical models, and the clinical significance remains uncertain. The study contributes to the understanding of neurotensin's potential when modified for better brain access.
Key findings
- VH-N412 induced rapid hypothermia in mice.
- VH-N412 showed anticonvulsant effects in status epilepticus.
- VH-N412 reduced hippocampal inflammation.
- VH-N412 preserved learning and memory skills in treated mice.
- VH-N412 displayed neuroprotective properties in cultured neurons.
Limitations
- mouse model only
- no human data
- effect sizes not reported
- preclinical study
- short-term outcomes