Lentivirus-mediated downregulation of α-synuclein reduces neuroinflammation and promotes functional recovery in rats with spinal cord injury

Abstract

BackgroundThe prognosis of spinal cord injury (SCI) is closely related to secondary injury, which is dominated by neuroinflammation. There is evidence that α-synuclein aggregates after SCI and that inhibition of α-synuclein aggregation can improve the survival of neurons after SCI, but the mechanism is still unclear. This study was designed to investigate the effects of α-synuclein on neuroinflammation after SCI and to determine the underlying mechanisms.MethodA T3 spinal cord contusion model was established in adult male Sprague-Dawley rats. An SNCA-shRNA-carrying lentivirus (LV-SNCA-shRNA) was injected into the injury site to block the expression of α-synuclein (forming the SCI+KD group), and the SCI and sham groups were injected with an empty vector. Basso-Beattie-Bresnahan (BBB) behavioural scores and footprint analysis were used to detect motor function. Inflammatory infiltration and myelin loss were measured in the spinal cord tissues of each group by haematoxylin-eosin (HE) and Luxol Fast Blue (LFB) staining, respectively. Immunohistochemistry, Western blot analysis, and RT-qPCR were used to analyse protein expression and transcription levels in the tissues. Immunofluorescence was used to determine the morphology and function of glial cells and the expression of matrix metalloproteinase-9 in the central canal of the spinal cord. Finally, peripheral serum cytokine levels were determined by enzyme-linked immunosorbent assay.ResultsCompared with the SCI group, the SCI+KD group exhibited reduced inflammatory infiltration, preserved myelin, and functional recovery. Specifically, the early arrest of α-synuclein inhibited the pro-inflammatory factors IL-1β, TNF-α, and IL-2 and increased the expression of the anti-inflammatory factors IL-10, TGF-β, and IL-4. The neuroinflammatory response was regulated by reduced proliferation of Iba1+ microglia/macrophages and promotion of the shift of M1-polarized Iba1+/iNOS+ microglia/macrophages to M2-polarized Iba1+/Arg1+ microglia/macrophages after injury. In addition, compared with the SCI group, the SCI+KD group also exhibited a smaller microglia/astrocyte (Iba1/GFAP) immunostaining area in the central canal, lower MMP-9 expression, and improved cerebrospinal barrier function.ConclusionLentivirus-mediated downregulation of α-synuclein reduces neuroinflammation, improves blood-cerebrospinal barrier function, promotes functional recovery, reduces microglial activation, and promotes the polarization of M1 microglia/macrophages to an M2 phenotype to confer a neuroprotective immune microenvironment in rats with SCI.

Betulinic acid inhibits pyroptosis in spinal cord injury by augmenting autophagy via the AMPK-mTOR-TFEB signaling pathway

“…For example, previous studies revealed that AMPK-SPK2-CARM1 signaling pathway is another important pathway regulating TFEB in the nucleus 69 , 70 , and future investigations should explore whether BA also acts through AMPK -SPK2-CARM1-TFEB signaling pathway in SCI. 28-days slices were commonly used for histological evaluation in SCI animals 71 , 72 . This is necessary to be performed for SCI in the future.…”

Reducing Suppressors of Cytokine Signaling-3 (SOCS3) Expression Promotes M2 Macrophage Polarization and Functional Recovery After Intracerebral Hemorrhage

“…In addition, it has been suggested that M1 polarization is toxic to neurons, while M2 cells facilitate tissue repair (5). To date, most studies on microglial/macrophage phenotypes have focused on traumatic brain injuries, cerebral ischemia, and spinal cord injury (6)(7)(8)(9)(10). However, the polarization of microglia/macrophages following intracerebral hemorrhage (ICH) has not been well-studied.…”

Ketogenic Diet-mediated Steroid Metabolism Reprogramming Improves the Immune Microenvironment and Myelin Growth of Spinal Cord Injury Rats Through Gene Analysis and Co-expression Network Analysis

“…In SCI secondary injury, in ammation is an important and main pathophysiological process. After SCI, ischaemia-reperfusion injury, endothelial cell injury and homeostasis disorders jointly initiate the in ammatory cascade reaction, and spinal cord innate immune cells (microglia and astrocytes) [40] and in ltrating white blood cells (neutrophils and macrophages) are activated [40][41]. The activated in ammatory cells release a large number of in ammatory factors to further expand the damage and increase the time and space of the damage response.…”