5-Nonyloxytryptamine oxalate-embedded collagen-laminin scaffolds augment functional recovery after spinal cord injury in mice

Leaf extracts of eight selected southern African medicinal plants modulate pro-inflammatory cytokine secretion in LPS-stimulated RAW 264.7 macrophages

This study investigates the anti-inflammatory properties of extracts prepared from the leaves of eight southern African medicinal plants used traditionally to treat inflammation and pain. The inhibitory effect of aqueous and ethanol extracts on the release of pro-inflammatory cytokines was determined in lipopolysaccharide (LPS) stimulated and unstimulated RAW 264.7 murine macrophage cells. The levels of interleukin (IL)-1β, IL-6, tumour necrosis factor-α (TNF-α), interferon-gamma (IFN-γ), monocyte chemoattractant protein 1 (MCP-1) and macrophage inflammatory protein (MIP)-2 release were determined using cytokine multiplex-bead assays. The ethanol extracts of Melianthus comosus Vahl (commonly known as honey flower), Tetradenia riparia (Hochst.) Codd (misty plume bush) and Warburgia salutaris (G. Bertol.) Chiov. (pepper-bark tree), demonstrated the most significant inhibitory activity, with over 50-fold inhibition of IL-1β, IL-6 and TNF-α levels in LPS-stimulated RAW 264.7 macrophages. The aqueous extract of M. comosus also significantly inhibited the secretion of all the tested cytokines and chemokines. Phytochemical investigation of M. comosus ethanol leaf extract using ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-HRMS) led to the detection of crassolide, deoxylimonoic acid D-ring-lactone, 2-hydroxynonanoic acid and 5-noniloxytryptamine. To the best of our knowledge, the cytokine inhibition properties of most of the medicinal plants screened in this study are reported for the first time. Our results support the use of southern African medicinal plants as anti-inflammatory remedies and provide an insight into the immunomodulatory mechanisms of action.

VEGFA-modified DPSCs combined with LC-YE-PLGA NGCs promote facial nerve injury repair in rats

Objective

The aim of this research was to investigate the effect of vascular endothelial growth factor A (VEGFA)-overexpressing rat dental pulp stem cells (rDPSCs) combined with laminin-coated and yarn-encapsulated poly(_l-lactide-co-glycolide) (PLGA) nerve guidance conduit (LC-YE-PLGA NGC) in repairing 10 mm facial nerve injury in rats.

Study Design

rDPSCs isolated from rat mandibular central incisor were cultured and identified in vitro and further transfected with the lentiviral vectors (Lv-VEGFA). To investigate the role and mechanisms of VEGFA in neurogenic differentiation in vitro, semaxanib (SU5416), Cell Counting Kit-8 (CCK-8), real-time quantitative polymerase chain reaction (qPCR) and Western blotting were performed. Ten-millimeter facial nerve defect models in rats were established and bridged by LC-YE-PLGA NGCs. The repair effects were detected by transmission electron microscopy (TEM), compound muscle action potential (CMAP), immunohistochemistry and immunofluorescence.

Results

Extracted cells exhibited spindle-shaped morphology, presented typical markers (CD44⁺CD90⁺CD34^-CD45^-), and presented multidirectional differentiation potential. The DPSCs with VEGFA overexpression were constructed successfully. VEGFA enhanced the proliferation and neural differentiation ability of rDPSCs, and the expression of neuron-specific enolase (NSE) and βIII-tubulin was increased. However, these trends were reversed with the addition of SU5416. This suggests that VEGFA mediates the above effects mainly through vascular endothelial growth factor receptor 2 (VEGFR2) binding. The LC-YE-NGC basically meet the requirements of facial nerve repair. For the in vivo experiment, the CMAP latency period was shorter in DPSCS-VEGFA-NGC group in comparison with other experimental groups, while the amplitude was increased. Such functional recovery correlated well with an increase in histological improvement. Further study suggested that VEGFA-modified DPSCs could increase the myelin number, thickness and axon diameter of facial nerve. NSE, βIII-tubulin and S100 fluorescence intensity and immunohistochemical staining intensity were significantly enhanced.

Conclusion

VEGFA-modified rDPSCs combined with LC-YE-PLGA NGCs have certain advantages in the growth and functional recovery of facial nerves in rats.

Current Concepts of Biomaterial Scaffolds and Regenerative Therapy for Spinal Cord Injury

Spinal cord injury (SCI) is a catastrophic condition associated with significant neurological deficit and social and financial burdens. It is currently being managed symptomatically, with no real therapeutic strategies available. In recent years, a number of innovative regenerative strategies have emerged and have been continuously investigated in preclinical research and clinical trials. In the near future, several more are expected to come down the translational pipeline. Among ongoing and completed trials are those reporting the use of biomaterial scaffolds. The advancements in biomaterial technology, combined with stem cell therapy or other regenerative therapy, can now accelerate the progress of promising novel therapeutic strategies from bench to bedside. Various types of approaches to regeneration therapy for SCI have been combined with the use of supportive biomaterial scaffolds as a drug and cell delivery system to facilitate favorable cell-material interactions and the supportive effect of neuroprotection. In this review, we summarize some of the most recent insights of preclinical and clinical studies using biomaterial scaffolds in regenerative therapy for SCI and summarized the biomaterial strategies for treatment with simplified results data. One hundred and sixty-eight articles were selected in the present review, in which we focused on biomaterial scaffolds. We conducted our search of articles using PubMed and Medline, a medical database. We used a combination of "Spinal cord injury" and ["Biomaterial", or "Scaffold"] as search terms and searched articles published up until 30 April 2022. Successful future therapies will require these biomaterial scaffolds and other synergistic approaches to address the persistent barriers to regeneration, including glial scarring, the loss of a structural framework, and biocompatibility. This database could serve as a benchmark to progress in future clinical trials for SCI using biomaterial scaffolds.

The Application of Biomaterials in Spinal Cord Injury

The spinal cord and the brain form the central nervous system (CNS), which is the most important part of the body. However, spinal cord injury (SCI) caused by external forces is one of the most difficult types of neurological injury to treat, resulting in reduced or even absent motor, sensory and autonomic functions. It leads to the reduction or even disappearance of motor, sensory and self-organizing nerve functions. Currently, its incidence is increasing each year worldwide. Therefore, the development of treatments for SCI is urgently needed in the clinic. To date, surgery, drug therapy, stem cell transplantation, regenerative medicine, and rehabilitation therapy have been developed for the treatment of SCI. Among them, regenerative biomaterials that use tissue engineering and bioscaffolds to transport cells or drugs to the injured site are considered the most promising option. In this review, we briefly introduce SCI and its molecular mechanism and summarize the application of biomaterials in the repair and regeneration of tissue in various models of SCI. However, there is still limited evidence about the treatment of SCI with biomaterials in the clinic. Finally, this review will provide inspiration and direction for the future study and application of biomaterials in the treatment of SCI.

Targeting sialylation to treat central nervous system diseases

Sialic acid-binding immunoglobulin-type lectins (SIGLECs) are membrane receptors that are preferentially expressed on immune cells and recognize sialylated proteins, lipids, and RNA. Sialic acids and signaling through SIGLECs are increasingly recognized for their essential roles in immune system homeostasis as well as nervous system development, plasticity, and repair. Dysregulated sialylation and SIGLEC dysfunctions contribute to several chronic diseases of the central nervous system (CNS) in which current therapeutic options are very limited. While only a few therapies targeting SIGLECs are currently being tested in clinical trials, the area emerged as one of the most dynamic and active fields in glycobiology and drug development. This review highlights recent insights into sialic acid and SIGLEC function in CNS pathologies and illustrates opportunities and challenges for the development of sialic acid-based and SIGLEC-targeted therapies for neurological diseases.

Importance of brain alterations in spinal cord injury

Spinal cord injury (SCI) destroys the sensorimotor pathway and blocks the information flow between the peripheral nerve and the brain, resulting in autonomic function loss. Numerous studies have explored the effects of obstructed information flow on brain structure and function and proved the extensive plasticity of the brain after SCI. Great progress has also been achieved in therapeutic strategies for SCI to restore the "re-innervation" of the cerebral cortex to the limbs to some extent. Although no thorough research has been conducted, the changes of brain structure and function caused by "re-domination" have been reported. This article is a review of the recent research progress on local structure, functional changes, and circuit reorganization of the cerebral cortex after SCI. Alterations of structure and electrical activity characteristics of brain neurons, features of brain functional reorganization, and regulation of brain functions by reconfigured information flow were also explored. The integration of brain function is the basis for the human body to exercise complex/fine movements and is intricately and widely regulated by information flow. Hence, its changes after SCI and treatments should be considered.

PSA mimetic 5-nonyloxytryptamine protects cerebellar neurons against glutamate induced excitotoxicity: An in vitro perspective

PSA-NCAM is a molecule of therapeutic interest for its key role in promoting neuritogenesis and synaptic plasticity. The current study was aimed to investigate the neuroregenerative potential of 5-nonyloxytryptamine (5-NOT) as PSA mimetic compound against glutamate induced excitotoxicity. 2D and 3D cultures of cerebellar neurons challenged with glutamate were used to ascertain the effect of 5-NOT on neurite outgrowth, migration and expression of neuronal plasticity markers. Glutamate excitotoxicity is one of the major underlying pathological factor responsible for neurodegeneration in various neurological disorders such as trauma, stroke, ischemia, epilepsy and neurodegenerative diseases.5-NOT treatment was observed to promote axonal growth and defasiculation in glutamate challenged neurons as well as promoted the migration of cerebellar neurons in both wound scratched area and cerebellar explant cultures. Further, 5-NOT treatment upregulated the expression of synaptic plasticity and cell survival pathway proteins which showed reduced expression after glutamate induced excitotoxicity. Thus, this preliminary data reveals thatPSA-mimetic,5-NOT may prove to be a potential neuroprotective candidate for neurodegenerative diseases.

Functions of Small Organic Compounds that Mimic the HNK-1 Glycan

Because of the importance of the HNK-1 carbohydrate for preferential motor reinnervation after injury of the femoral nerve in mammals, we screened NIH Clinical Collection 1 and 2 Libraries and a Natural Product library comprising small organic compounds for identification of pharmacologically useful reagents. The reason for this attempt was to obviate the difficult chemical synthesis of the HNK-1 carbohydrate and its isolation from natural sources, with the hope to render such compounds clinically useful. We identified six compounds that enhanced neurite outgrowth from cultured spinal motor neurons at nM concentrations and increased their neurite diameter, but not their neurite branch points. Axons of dorsal root ganglion neurons did not respond to these compounds, a feature that is in agreement with their biological role after injury. We refer to the positive functions of some of these compounds in animal models of injury and delineate the intracellular signaling responses elicited by application of compounds to cultured murine central nervous system neurons. Altogether, these results point to the potential of the HNK-1 carbohydrate mimetics in clinically-oriented settings.