Semax

Abstract

Therapeutic peptides are emerging as promising adjuncts in the management of orthopaedic injuries, grounded in their ability to modulate molecular signaling networks central to cellular medicine. By acting on key pathways such as PI3K/Akt, mTOR, MAPK, TGF-β, and AMPK, peptides exert influence over tissue regeneration, inflammation resolution, and neuromuscular recovery. Wound-healing peptides such as BPC-157, TB-500, and GHK-Cu promote angiogenesis, integrin-mediated extracellular matrix remodeling, and fibroblast activation, whereas growth hormone secretagogues like ipamorelin, CJC-1295, tesamorelin, sermorelin, and AOD-9604 activate IGF-1 signaling and satellite cell repair. Recovery-enhancing agents such as epithalon, delta sleep-inducing peptide, and pinealon target circadian and mitochondrial regulators, and neuroactive peptides like selank, semax, and dihexa enhance brain-derived neurotrophic factor and HGF/c-Met pathways critical to neuroplasticity. Although preclinical studies are promising, there is a current lack of clinical trials. This review integrates current mechanistic insights with orthopaedic relevance, emphasizing safety, efficacy, and future directions for responsible integration into musculoskeletal care.

Abstract

Alzheimer's disease, first described over a century ago, is currently among the most common neurodegenerative diseases whose significance is increasingly growing with the aging of populations. Throughout the entire period of its study, no remedies have been found that would be effective in treating - or at least significantly slowing - the pathological process, while being sufficiently safe. In this regard, significant attention is paid to the development and application of natural peptide drugs lacking side effects. The present study assessed the effect of the known neuroprotective peptide Semax and its derivative on the behavioral characteristics and development of amyloidosis in transgenic APPswe/PS1dE9/Blg mice acting as a model of Alzheimer's disease. The open field, novel object recognition, and Barnes maze tests demonstrated that both Semax and its derivative improved cognitive functions in mice. Histological examination showed that these peptides reduced the number of amyloid inclusions in the cortex and hippocampus of the animals' brains. These findings demonstrate the high potential of Semax and its derivatives when used to develop therapeutic and corrective strategies for Alzheimer's disease.

Abstract

Spinal cord injury (SCI) is a damage to the spinal cord caused mainly by trauma resulting in major motor, sensory and autonomic dysfunctions. Its final neurological outcome is determined by both primary and secondary injury processes. A key component of secondary injury mechanisms after initial trauma is neuroinflammation. A neuroprotective compound, ACTH 4-10Pro 8-Gly 9-Pro 10 (ACTH 4-10) also known as semax, has shown neuroprotective and anti-inflammatory properties. ACTH 4-10 has also been actively used in the treatment of brain ischemia without serious complication reported. Here, we analyzed the effects of ACTH 4-10 at regulating the inflammatory cascade in SCI by looking at anti-inflammatory cytokine (IL-4, IL-10 and IL-13) levels after acute SCI.

Abstract

We studied the effects of Semax on spontaneous fluctuations of intracellular calcium ion concentration [Ca2+]i in pyramidal neurons on hippocampal slices and on proton-induced increase in [Ca2+]i in cerebellar granule cells in cerebellar slices. Application of Semax (1 μM), significantly increased the frequency of spontaneous [Ca2+]i fluctuations in the pyramidal layer cells of the hippocampal CA1 field, but had no significant effect on proton-stimulated increase in [Ca2+]i in cerebellar granule cells. These data provide insight into the localization of cellular targets and elucidate the dynamics of the initial stages of interaction between the peptide and the hippocampal neuronal network. The primary mechanism of the neuroprotective effect of Semax appears to be unrelated to attenuation of calcium entry through acid-sensing ion channels in cerebellar granule cells.

Abstract

Neurodegenerative disorders (NDDs) pose a growing global health burden, primarily due to their progressive nature and the limited efficacy of existing treatments. Bioactive peptides and proteins/polypeptides, particularly those derived from dietary and natural sources, show promise in modulating neurobiological pathways central to neurodegeneration. This review aims to critically examine the neuroprotective roles of Bioactive peptides and proteins/polypeptides in NDDs, elucidating their mechanisms of action, potential therapeutic applications in conditions like Alzheimer's, Parkinso's disease, Huntington's disease, and others, as well as the trends in peptide-based therapeutics. Bioactive peptides and proteins/polyspeptides, such as NGF, BDNF, GDNF, Semax, and Exendin-4, have been found to modulate several critical mechanisms, including the reduction of oxidative stress (OS), inhibition of neuroinflammation, preservation of mitochondria, and enhancement of synaptic plasticity. These peptides have demonstrated efficacy in preclinical and early-phase clinical trials across a spectrum of NDDs. Delivery challenges, such as blood-brain barrier (BBB) permeability and enzymatic degradation, have been acknowledged. Ongoing innovations in peptide engineering, nanoparticle-based delivery systems, CRISPR-assisted design, and AI-driven screening are addressing these limitations. By targeting multiple pathogenic mechanisms simultaneously, peptide-based therapeutics present a rational and innovative approach to NDD management. Their multifunctional action profiles and ability to target specific molecular pathways highlight their potential as next-generation neuroprotective agents. However, future clinical validation and advanced strategies are essential for translating these promising molecules into effective treatments.

Abstract

Lysosomal membrane permeabilization (LMP) is exacerbated following spinal cord injury (SCI), leading to increased neuronal cell death. Ubiquitination may affect LMP by regulating the stability and functionality of lysosomal membranes. Semax, a synthetic heptapeptide, comprising the ACTH (4-7) fragment and a C-terminal Pro-Gly-Pro tripeptide, exhibits neuroprotective properties and improves cognitive function. Given the key roles of LMP and ubiquitination in SCI pathophysiology, this study investigated how Semax could modulate these pathways to affect functional recovery following SCI.

Abstract

In the treatment of ischemic stroke, an innovative approach is the use of neuroprotective compounds. Natural peptides, including adrenocorticotropic hormone (ACTH), can serve as the basis for such drugs. Previously, a significant effect of non-hormonal ACTH(4-7)PGP (Semax) and ACTH(6-9)PGP peptides on the functions of the nervous system was shown. Also, while using RNA-Seq, we firstly revealed differentially expressed genes (DEGs) that associated with peptides in the penumbra-associated region of the frontal cortex (FC) of rats at 24 h after transient middle cerebral artery occlusion (tMCAO) model. Peptides significantly reduced profile disturbances caused by ischemia for almost two-thousand DEGs in FC related to the neurotransmitter and inflammatory response. Here, we studied how peptides affected the expression of genes in the striatum with an ischemic focus, predominantly. The same animals from which we previously acquired FC were used to collect striatum samples. Peptides generated fewer DEGs in the striatum than in the FC. Both peptides tended to normalize the profile of disturbances caused by ischemia for hundreds of DEGs, whereas 152 genes showed an even more affected profile in the striatum under ACTH(6-9)PGP action. These DEGs were associated with inflammation, predominantly. About hundred genes were overlapped between both peptides in both tissues and were associated with neuroactive ligand-receptor interaction, predominantly. Thus, genes that are associated with the ACTH-like peptide action in rat brain regions with varying levels of ischemia injury were identified. Moreover, differential spatial regulation of the ischemia process in the rat brain at the transcriptome levels was discovered under peptides with different ACTH structures. We suppose that our results may be useful for selecting more effective neuroprotective drug structures in accordance with their specific tissue/damage therapeutic impact.

Abstract

Alzheimer's disease (AD) is the most common neurodegenerative disorder associated with cognitive decline and loss of memory. It is postulated that the generation of reactive oxygen species (ROS) in Fenton-like reaction connected with Cu(II)/Cu(I) redox cycling of the Cu(II)-aβ complex can play a key role in the molecular mechanism of neurotoxicity in AD. Semax (Met-Glu-His-Phe-Pro-Gly-Pro) is a synthetic regulatory peptide that possesses a high affinity for Cu(II) ions. The ability of the peptide Semax to inhibit the copper-catalyzed oxidation of aβ was studied in vitro and discussed. The results indicate that Semax is able to extract Cu(II) from Cu(II)-aβ species as well as to influence the redox cycling of the Cu(II)-aβ complex and decrease the level of associated ROS production. Finally, our data suggest that Semax shows cytoprotective properties for SH-SY5Y cells against oxidative stress induced by copper-catalyzed oxidation of the aβ peptide. This study provides valuable insights into the potential role of Semax in neurodegenerative disorders and into the design of new compounds with therapeutic potential for AD.