Monoamine oxidase-B inhibitor protects degenerating spinal neurons, enhances nerve regeneration and functional recovery in sciatic nerve crush injury model

Effects of Monoamino-Oxidase-A (MAO-A) Inhibition on Skeletal Muscle Inflammation and Wasting through Pancreatic Ductal Adenocarcinoma in Triple Transgenic Mice

Cancer cachexia describes a syndrome of muscle wasting and lipolysis that is still largely untreatable and negatively impacts prognosis, mobility, and healthcare costs. Since upregulation of skeletal muscle monoamine-oxidase-A (MAO-A), a source of reactive oxygen species, may contribute to cachexia, we investigated the effects of the MAO-inhibitor harmine-hydrochloride (HH, intraperitoneal, 8 weeks) on muscle wasting in a triple-transgenic mouse model of pancreatic ductal adenocarcinoma (PDAC) and wild type (WT) mice. Gastrocnemius and soleus muscle cryo-cross-sections were analyzed for fiber type-specific cross-sectional area (CSA), fraction and capillarization using ATPase- and lectin-stainings. Transcripts of pro-apoptotic, -atrophic, and -inflammatory signals were determined by RT-qPCR. Furthermore, we evaluated the integrity of neuromuscular junction (NMJ, pre-/post-synaptic co-staining) and mitochondrial ultrastructure (transmission electron microscopy). MAO-A expression in gastrocnemius muscle was increased with PDAC vs. WT (immunohistochemistry: p < 0.05; Western blot: by trend). PDAC expectedly reduced fiber CSA and upregulated IL-1β in both calf muscles, while MuRF1 expression increased in soleus muscle only. Although IL-1β decreased, HH caused an additional 38.65% (p < 0.001) decrease in gastrocnemius muscle (IIBX) fiber CSA. Moreover, soleus muscle CSA remained unchanged despite the downregulation of E3-ligases FBXO32 (p < 0.05) and MuRF1 (p < 0.01) through HH. Notably, HH significantly decreased the post-synaptic NMJ area (quadriceps muscle) and glutathione levels (gastrocnemius muscle), thereby increasing mitochondrial damage and centronucleation in soleus and gastrocnemius type IIBX fibers. Moreover, although pro-atrophic/-inflammatory signals are reversed, HH unfortunately fails to stop and rather promotes PDAC-related muscle wasting, possibly via denervation or mitochondrial damage. These differential adverse vs. therapeutic effects warrant studies regarding dose-dependent benefits and risks with consideration of other targets of HH, such as the dual-specificity tyrosine phosphorylation regulated kinases 1A and B (DYRK1A/B).

Effect of selegiline as a monomine oxidase B inhibitor on the expression of neurotrophin mRNA levels in a contusion rat model of spinal cord injury

OBJECTIVE

Spinal cord injury (SCI) is followed by a cascade of events at the site of injury, including vascular ischemia, an increase in free radicals, inflammation, and neuronal death. In these individuals, protection of nerves and supporting cells, as well as prevention of neuronal damage, may improve recovery opportunities. Neurotrophins are a family of polypeptides that regulate nerve differentiation, growth, and survival. Selegiline is a selective monoamine oxidase B (MAO-B) inhibitor used to treat Parkinson's disease. Selegiline has been found to have neuroprotective properties and may be useful for the expression of neurotrophins. The aim of this study was to evaluate the expression levels of neurotrophin genes in spinal cord rats treated with selegiline.

METHODS

Rats were divided into four groups: injury (control), laminectomy, sham (injured rat received 1 ml saline intraperitoneally) and treatment (injured rat received 5 mg/kg selegiline intraperitoneally for 7 days; once a day). The BBB scale (Basso, Beattie and Bresnahan) was performed once a week for 4 weeks to assess motor function after a spinal cord injury. On day 28 after SCI, the rat was sacrificed and the spinal cord lesion removed. A real-time PCR approach was used to assess neurotrophin gene expression.

RESULTS

The results showed that administration of selegiline improves locomotor function and increases mRNA levels of BDNF, GDNF, NT-3, and NT-4.

CONCLUSION

In summary, the results of this study suggest that selegiline may be an appropriate treatment for spinal cord injuries.

Khellin as a selective monoamine oxidase B inhibitor ameliorated paclitaxel-induced peripheral neuropathy in mice

BACKGROUND

Treatment of paclitaxel (PTX)-induced peripheral neuropathy (PIPN) is full of challenges because of the unclear pathogenesis of PIPN. Herbal folk medicine Khellin (Khe) is a natural compound extracted from Ammi visnaga for treatment of renal colics and muscle spasms.

PURPOSE

Here, we aimed to assess the potential of Khe in ameliorating PIPN-like pathology in mice and investigate the underlying mechanisms.

METHODS

PIPN model mice were conducted by injection of PTX based on the published approach. The capability of Khe in ameliorating the PTX-induced neurological dysfunctions was assayed by detection of nociceptive hypersensitivities including mechanical hyperalgesia, thermal hypersensitivity, and cold allodynia in mice. The underlying mechanisms were investigated by assays against the PIPN mice with MAOB-specific knockdown in spinal cord and dorsal root ganglion (DRG) tissues by injection of adeno-associated virus (AAV)-MAOB-shRNA.

RESULTS

We determined that MAOB not MAOA is highly overexpressed in the spinal cord and DRG tissues of PIPN mice and Khe as a selective MAOB inhibitor improved PIPN-like pathology in mice. Khe promoted neurite outgrowth, alleviated apoptosis, and improved mitochondrial dysfunction of DRG neurons by targeting MAOB. Moreover, Khe inhibited spinal astrocytes activation and suppressed neuroinflammation of spinal astrocytes via MAOB/NF-κB/NLRP3/ASC/Caspase1/IL-1β pathway.

CONCLUSION

Our work might be the first to report that MAOB not MAOA is selectively overexpressed in the spinal cord and DRG tissues of PIPN mice, and all findings have highly addressed the potency of selective MAOB inhibitor in the amelioration of PIPN-like pathology and highlighted the potential of Khe in treating PTX-induced side effects.

Catfish Epidermal Preparation Accelerates Healing of Damaged Nerve in a Sciatic Nerve Crush Injury Rat Model

Preliminary investigations showed that preparations from Arabian Gulf catfish (Arius bilineatus, Val) epidermal gel secretion (PCEGS) exhibit potent anti-inflammatory and healing properties as shown in our previous clinical trials for the healing of non-healing diabetic foot ulcers, chronic back pain, and some other neurological disorders. Here, we report for the first time a unique preparation containing only proteins and lipids (soluble protein fraction B, SPF-FB), derived from the PCEGS accelerated the healing and recovery of sensory-motor functions of experimental sciatic nerve crush injury in rats with its unique neuroprotective and neuroregenerative properties on the spinal neurons and peripheral nerve fibers. Male rats were randomly assigned to five groups: (I) NAÏVE, (II) SHAM, (III) CRUSH treated with saline, (IV) CRUSH + SPF-FB treated with 3 mg/kg intraperitoneally (IP) and (V) CRUSH + SPF-FB treated with 6 mg/kg subcutaneously (SC) groups. The crush groups III, IV and V underwent sciatic nerve crush injury, followed by treatment daily for 14 days with saline, SPF-FB IP and SPF-FB SC. All animals were tested for the neurobehavioral parameters throughout the 6 weeks of the study. Sciatic nerve and spinal cord tissues were processed for light and electron histological examinations, stereological analysis, immunohistochemical and biochemical examinations at Week 4 and Week 6 post-injury. Administration of SPF-FB IP or SC significantly enhanced the neurobehavioral sensory and motor performance and histomorphological neuroregeneration of the sciatic nerve-injured rats. The stereological evaluation of the axon area, average axon perimeters, and myelin thickness revealed significant histomorphological evidence of neuroregeneration in the FB-treated sciatic nerve crush injured groups compared to controls at 4 and 6 weeks. SPF-FB treatment significantly prevented the increased in NeuN-immunoreactive neurons, increased GFAP immunoreactive astrocytes, and decreased GAP-43. We conclude that SPF-FB treatment lessens neurobehavioral deficits, enhances axonal regeneration following nerve injury. We conclude that SPF-FB treatment lessens neurobehavioral deficits and enhances axonal regeneration following nerve injury, as well as protects spinal neurons and enhances subcellular recovery by increasing astrocytic activity and decreasing GAP-43 expression.

Effectiveness of Selegiline Hydrochlorate in Treating Neurosensory Disorders of the Lower Alveolar Nerve Resulting From Mandibular Sagittal Osteotomy: Preliminary Study

INTRODUCTION

Peripheral nerves transmit nerve signals between periphery and the spinal cord or brain stem. Its function can be compromised by trauma to the nerve, such as those that occur in surgical procedures such as orthognathic surgery. Depending on the type of injury, treatment may be proposed, but this is still a controversial point in literature. Alternative methods that assist in the treatment of paresthesia should be studied, and in this context, selegiline hydrochloride seems to be a promising drug.

AIM

Based on the above, the aim of this study was to evaluate the effectiveness of selegiline hydrochloride in the treatment of facial sensory changes resulting from nerve injuries in patients undergoing maxillary orthognathic surgery.

METHODS

This was a double-blind randomized clinical trial with the voluntary participation of individuals who underwent orthognathic surgery. The facial sensitivity of these patients was evaluated by 2-point discrimination tests and directional perception in the region related to the lower alveolar nerve. Tests were comparatively applied at times T0 (before surgery), T8 (8 days after surgery), T15 (15 days after surgery), T30 (30 days after surgery), T60 (60 days after surgery), and T90 (90 days after surgery).

RESULTS

The mean age of patients was 31.14 years. With the comparative analysis of the 2-point static test on the chin, difference was observed between groups at times T15 (P = 0.007), T30 (P = 0.010), and T90 (P = 0.027) in the intergroup evaluation. Regarding results of the comparative analysis of the 2-point static test on the lip, difference was observed between groups at times T30 (P = 0.023), T60 (P < 0.001), and T90 (P = 0.005) in the intergroup evaluation. In the direction test on the chin, difference was observed between groups at times T30 (P = 0.015), T60 (P = 0.001), and T90 (P < 0.001) in the intergroup evaluation.

CONCLUSIONS

Selegiline hydrochloride has shown promising results in the treatment of neurosensory disorders resulting from maxillary orthognathic surgery.

Resveratrol regulates the recovery of rat sciatic nerve crush injury by promoting the autophagy of Schwann cells

Resveratrol has the ability to promote functional recovery after sciatic nerve crush injury (SNCI), though the mechanism through which this occurs in not fully understood. Resveratrol can promote autophagy, a key process in Wallerian degeneration; thus, we hypothesized that resveratrol could promote recovery from SNCI by promoting Schwann cell autophagy and acceleration of Wallerian degeneration. Motor function recovery was assessed by calculating Sciatic Function Indexes (SFIs) at days 7, 14, 21, 28 post SNCI. Autophagy and myelin clearance were assessed by microtubule-associated protein light chain 3B (LC3B) and myelin protein zero (MPZ) immunofluorescence and Western blot analysis on the fourth day after SNCI. The autophagy of Schwann cells following resveratrol administration was quantified by immunofluorescence in RSC96 cells. Immunofluorescence and Transmission electron microscopy (TEM) were also used in Resveratrol treated sciatic nerve four days post-SNCI to find LC3B positive areas and typical double membrane structures represent for autophagy. The SNCI+resveratrol (crush+Res) groups recovered faster than the SNCI+vehicles (crush+V) group. On day four, almost all of the myelin had regenerated in the crush+Res rats, while the crush+V group's myelin remained intact and the expression levels of LC3-II/I was the highest. On day 28 post-injury, both the control and crush+Res groups' myelin neurofibers reached peak numbers as did the thickness of the myelin sheath. Both in vitro and in vivo immunofluorescence showed that LC3B was colocalized with Schwann cells. This is the first study to observe that resveratrol can promote recovery from SCNI by accelerating the myelin clearance process by promoting autophagy of Schwann cells.

Neurotherapeutic effects of Ginkgo biloba extract and its terpene trilactone, ginkgolide B, on sciatic crush injury model: A new evidence

Ginkgo biloba leaves extract (GBE) was subjected to neuroprotective-guided fractionation to produce eleven fractions with different polarities and constituents. The intermediate polar fraction was shown to be terpene trilactones-enriched fraction (TEGBE). Out of this fraction, pure ginkgolide B (G-B) was further purified and identified based on its spectral data. The effects of GBE and TEGBE were evaluated in comparison to that of G-B in the crush sciatic nerve injury rat model. To evaluate the neuroprotective effects, sixty Wistar male rats were randomly allocated into 6 groups: naive, sham, crush + normal saline, and three treatment groups; crush + GBE, crush + TEGBE, and crush + G-B. Treatments were given one hour following injury, and once daily for 14 days. Neurobehavioral tests, histomorphological examinations, and immunohistochemical analysis of the sciatic nerve and the spinal cord were performed at weeks 3 and 6 post-injury. GBE, TEGBE and G-B were shown to enhance the functional and sensory behavioral parameters and to protect the histological and the ultrastructural elements in the sciatic nerve. Additionally, all treatments prevented spinal cord neurons from further deterioration. It was shown that G-B has the most significant potential effects among all treatments with values that were nearly comparable to those of sham and naive groups.

miR-522 facilitates the prosperities of endometrial carcinoma cells by directly binding to monoamine oxidase B

It is well known that microRNAs (miRNAs) are crucial regulatory factors in tumorigenesis, as tumor suppressors or cancer-promoting factors. However, the study of endometrial carcinoma relevance in miR-522 is rare, indicating an undefined molecular mechanism for its role. Therefore, we performed this study to examine the role of miR-522 on the biological behaviors of endometrial carcinoma. In this work, we found that miR-522 was highly expressed in endometrial carcinoma and negatively regulated monoamine oxidase B (MAOB) expression. They also have the opposite effect on prognosis of endometrial carcinoma patients. More importantly, miR-522 could decreased MAOB expression by binding to MAOB with a putative site, thereby promoting cell proliferation, migration, and invasion through in vitro functional analyses, including MTT assay, wound-healing and transwell invasion experiments. Upregulation of MAOB rescued the impacts of miR-522 mimic on cell behaviors. In conclusion, our observations demonstrated that miR-522 accelerated the progression of endometrial carcinoma by inhibiting MAOB, which might lead to a novel therapeutic therapy for endometrial carcinoma.