RSC96 Schwann Cell Proliferation and Survival Induced by Dilong through PI3K/Akt Signaling Mediated by IGF-I

Pharmacological effects of bioactive agents in earthworm extract: A comprehensive review

This review compiles information from the literature on the chemical composition, pharmacological effects, and molecular mechanisms of earthworm extract (EE) and suggests possibilities for clinical translation of EE. We also consider future trends and concerns in this domain. We summarize the bioactive components of EE, including G-90, lysenin, lumbrokinase, antimicrobial peptides, earthworm serine protease (ESP), and polyphenols, and detail the antitumor, antithrombotic, antiviral, antibacterial, anti-inflammatory, analgesic, antioxidant, wound-healing, antifibrotic, and hypoglycemic activities and mechanisms of action of EE based on existing in vitro and in vivo studies. We further propose the potential of EE for clinical translation in anticancer and lipid-modifying therapies, and its promise as source of a novel agent for wound healing and resistance to antibiotic tolerance. The earthworm enzyme lumbrokinase embodies highly effective anticoagulant and thrombolytic properties and has the advantage of not causing bleeding phenomena due to hyperfibrinolysis. Its antifibrotic properties can reduce the excessive accumulation of extracellular matrix. The glycolipoprotein extract G-90 can effectively scavenge reactive oxygen groups and protect cellular tissues from oxidative damage. Earthworms have evolved a well-developed defense mechanism to fight against microbial infections, and the bioactive agents in EE have shown good antibacterial, fungal, and viral properties in in vitro and in vivo experiments and can alleviate inflammatory responses caused by infections, effectively reducing pain. Recent studies have also highlighted the role of EE in lowering blood glucose. EE shows high medicinal value and is expected to be a source of many bioactive compounds.

Decoding the mechanism of earthworm extract against wounds: an integrated metabolomics and network pharmacology study

Earthworms are used to cure wounds in Chinese villages for thousands of years. Recently, scientists realized their extracts could promote wound healing and they have anti-inflammatory, antioxidant, anti-apoptosis, and anti-microbial properties, but its mechanism of promoting wound healing remains unclear. In the presented study, electronic literature databases and LC-MS/MS were used to determine earthworms' ingredients and differential metabolites. Swiss Target Prediction database was used for ingredients' target prediction and wound disease-relevant genes were found from GeneCards, OMIM, and DrugBank databases. Network pharmacology was conducted to demonstrate filtering hub targets, biological functions, and the signaling pathways of earthworms extract against wounds. Molecular docking and metabolism analysis were used to look for core target genes and key bioactive molecules from earthworms. Finally, the investigation shows 5 most important signal pathways, 5 core genes, and 6 bioactive ingredients-related cell-cell adhesion, cell proliferation, and cell migration processes could be affected by earthworms' extract. On 3rd day, the extract could regulate HIF1A and EGFR targets to make the differences of quantities of 4-pyridoxate, tetradecanoic acid, and L-kynurenine. While on 7th day, the regulation refers 6 earthworms' bioactive ingredients, 4 core genes (CTNNB1, EGFR, SRC, and CASP3), and 4 differential metabolites (4-hydoxy-2-quinolinecarboxylic acid, urocanate, deoxyinosine, creatine, and sn-glycerol-3-phosphocholine). on 14th day, 2 core genes (EGFR, SRC) are influenced in the biological processes. Briefly, we found that 6 ingredients from earthworms have most bioactive and 5 core genes play an important role in promoting wound-healing processes. These discovers indicates earthworms could against wound via AGE-RAGE, PI3K-Akt, HIF1A, MAPK, and Axon guidance pathways.

L-carnitine ameliorates peripheral neuropathy in diabetic mice with a corresponding increase in insulin‑like growth factor‑1 level

Diabetic peripheral neuropathy (DPN) is one of the common complications in diabetes, affecting more than half of patients with diabetes. L‑carnitine (LC) was recently demonstrated to serve a positive role in ameliorating DPN. Therefore, the aim of the present study was to investigate the underlying mechanisms of LC in ameliorating DPN. Male Kunming mice were randomly assigned into five groups, including the control group, diabetes mellitus group, pre‑treatment group, treatment group and post‑treatment group. Type 2 diabetes was induced in mice using a combination of high‑fat diet and streptozotocin injection. Subsequently, peripheral neuropathy was measured and the levels of LC, insulin and insulin‑like growth factor‑1 (IGF‑1) were detected. When diabetic mice were treated with LC, the levels of IGF‑1 in the plasma and pancreas were increased. In addition, hyperalgesia, as determined by the tail‑flick test as well as food intake, body weight and blood glucose levels were decreased. An amelioration of demyelination, axonal atrophy and mitochondria swelling in the nerve fibres of diabetic mice was also observed. The present study demonstrated that LC ameliorated peripheral neuropathy in type 2 diabetic mice and the effect of LC may in part be mediated by an increase in local and circulatory IGF‑1 levels.

The Proliferation Enhancing Effects of Salidroside on Schwann Cells In Vitro

Derived from Rhodiola rosea L., which is a popular plant in Eastern Europe and Asia, salidroside has pharmacological properties including antiviral, anticancer, hepatoprotective, antidiabetic, and antioxidative effects. Recent studies show that salidroside has neurotrophic and neuroprotective effects. However, the effect of salidroside on Schwann cells (SCs) and the underlying mechanisms of the salidroside-induced neurotrophin secretion have seldom been studied. In this study, the effect of salidroside on the survival, proliferation, and gene expression of Schwann cells lineage (RSC96) was studied through the examinations of the cell viability, proliferation, morphology, and expression of neurotrophic factor related genes including BDNF, GDNF, and CDNF at 2, 4, and 6 days, respectively. These results showed that salidroside significantly enhanced survival and proliferation of SCs. The underlying mechanism might involve that salidroside affected SCs growth through the modulation of several neurotrophic factors including BDNF, GDNF, and CDNF. As for the concentration, 0.4 mM, 0.2 mM, and 0.1 mM of salidroside were recommended, especially 0.2 mM. This investigation indicates that salidroside is capable of enhancing SCs survival and function in vitro, which highlights the possibility that salidroside as a drug agent to promote nerve regeneration in cellular nerve scaffold through salidroside-induced neurotrophin secretion in SCs.

Baicalin promotes the viability of Schwann cells in vitro by regulating neurotrophic factors

The proliferation and migration of Schwann cells (SCs) are key events in the process of peripheral nerve repair. This is required to promote the growth of SCs and is a challenge during the treatment of peripheral nerve injury. Baicalin is a natural herb-derived flavonoid compound, which has been reported to possess neuroprotective effects on rats with permanent brain ischemia and neuronal differentiation of neural stem cells. The association of baicalin with neuroprotection leads to the suggestion that baicalin may exert effects on the growth of SCs. In the present study, the effects of baicalin on SCs of RSC96 were investigated. RSC96 SCs were treated with various concentrations of baicalin (0, 5, 10 or 20 µM) for 2, 4 and 6 days. Cell attachment, viability and gene expression were monitored via the MTT assay and reverse transcription-quantitative polymerase chain reaction. The gene expression levels of several neurotrophic factors, such as glial cell-derived neurotrophic factor, brain-derived neurotrophic factor and ciliary neurotrophic factor, which are considered important factors in the process of never cell regeneration, were detected. The results indicated that baicalin was able to promote the viability of RSC96 SCs in a dose-dependent manner and the concentration of 20 µM of baicalin exhibited the greatest cell viability and gene expression of the studied neurotrophic factors. The present findings suggested that baicalin likely affects SCs metabolism, through modulating the expression of neurotrophic factors. To conclude, the present study indicates that baicalin may be potential therapeutic agent for treating peripheral nerve regeneration.

Netrin-1 induces the migration of Schwann cells via p38 MAPK and PI3K-Akt signaling pathway mediated by the UNC5B receptor

Schwann cells (SCs) play an essentially supportive role in the regeneration of injured peripheral nerve system (PNS). As Netrin-1 is crucial for the normal development of nervous system (NS) and can direct the process of damaged PNS regeneration, our study was designed to determine the role of Netrin-1 in RSC96 Schwann cells (an immortalized rat Schwann cell line) proliferation and migration. Our studies demonstrated that Netrin-1 had no effect on RSC96 cells proliferation, while significantly promoted RSC96 cells migration. The Netrin-1-induced RSC96 cells migration was significantly attenuated by inhibition of p38 and PI3K through pretreatment with SB203580 and LY294002 respectively, but not inhibition of MEK1/2 and JNK by U0126-EtOH and SP600125 individually. Treatment with Netrin-1 enhanced the phosphorylation of p38 and Akt. QRT-PCR indicated that Netrin-1 and only its receptors Unc5a, Unc5b and Neogenin were expressed in RSC96 cells, among which Unc5b expressed the most. And UNC5B protein was significantly increased after stimulated by Netrin-1. In conclusion, we show here that Netrin-1-enhanced SCs migration is mediated by activating p38 MAPK and PI3K-Akt signal cascades via receptor UNC5B, which suggests that Netrin-1 could serve as a new therapeutic strategy and has potential application value for PNS regeneration.

Earthworm (Pheretima aspergillum) extract stimulates osteoblast activity and inhibits osteoclast differentiation

Background

The potential benefits of earthworm (Pheretima aspergillum) for healing have received considerable attention recently. Osteoblast and osteoclast activities are very important in bone remodeling, which is crucial to repair bone injuries. This study investigated the effects of earthworm extract on bone cell activities.

Methods

Osteoblast-like MG-63 cells and RAW 264.7 macrophage cells were used for identifying the cellular effects of different concentrations of earthworm extract on osteoblasts and osteoclasts, respectively. The optimal concentration of earthworm extract was determined by mitochondrial colorimetric assay, alkaline phosphatase activity, matrix calcium deposition, Western blotting and tartrate-resistant acid phosphatase activity.

Results

Earthworm extract had a dose-dependent effect on bone cell activities. The most effective concentration of earthworm extract was 3 mg/ml, significantly increasing osteoblast proliferation and differentiation, matrix calcium deposition and the expression levels of alkaline phosphatase, osteopontin and osteocalcin. Conversely, 3 mg/ml earthworm extract significantly reduced the tartrate-resistant acid phosphatase activity of osteoclasts without altering cell viability.

Conclusions

Earthworm extract has beneficial effects on bone cell cultures, indicating that earthworm extract is a potential agent for use in bone regeneration.

Neuroprotective effects of Buyang Huanwu decoction on cerebral ischemia-induced neuronal damage

Among the various treatment methods for stroke, increasing attention has been paid to traditional Chinese medicines. Buyang Huanwu decoction is a commonly used traditional Chinese medicine for the treatment of stroke. This paper summarizes the active components of the Chinese herb, which is composed of Huangqi (Radix Astragali seu Hedysari), Danggui (Radix Angelica sinensis), Chishao (Radix Paeoniae Rubra), Chuanxiong (Rhizoma Ligustici Chuanxiong), Honghua (Flos Carthami), Taoren (Semen Persicae) and Dilong (Pheretima), and identifies the therapeutic targets and underlying mechanisms that contribute to the neuroprotective properties of Buyang Huanwu decoction.

Effects of cerebrolysin on rat Schwann cells in vitro

Although the peripheral nervous system (PNS) is capable of regeneration, these processes are limited. As a potential means to augment PNS regeneration, the effects of cerebrolysin (CL), a proteolytic peptide fraction, were tested in vitro on Schwann cell (SC) proliferation, stress resistance, phagocytic and cluster-forming capacity. Primary SC/fibrocyte co-cultures were prepared from dorsal root ganglia of 5-7-day-old rats. SCs were subjected to mechanical stress by media change and metabolic stress by serum glucose deprivation (SGD). Cell survival was assessed using MTT test. SC proliferation was determined by counting BrdU-labeled cells. SC clustering was studied by ImageJ analysis of S100 immunostaining. Wallerian degeneration (WD) was evaluated by measuring acetylcholine-esterase staining within sciatic nerves in vitro. It was found that CL caused no effect on MTT turnover in the tested doses. CL inhibited SC proliferation in a dose-dependent manner. Media change and additional SGD stress inhibited SC clustering. CL enhanced the reorganization of SC clusters and was able to counteract SGD-induced cluster defects. Moreover, CL accelerated WD in vitro. CL was able to enhance the functions of SCs that are relevant to nerve regeneration. Thus, our findings suggest that CL may be suitable for therapeutic usage to enhance PNS regeneration/reconstruction.

Alpinia Oxyphylla Miquel Fruit Extract Activates MAPK-mediated Signaling of PAs and MMP2/9 to Induce Schwann Cell Migration and Nerve Regeneration

Objectives

This study investigates the molecular mechanisms by which Alpiniae oxyphyllae fructus (AOF) promotes neuron regeneration.

Methods

A piece of silicone rubber was guided across a 15 mm gap in the sciatic nerve of a rat. This nerve gap was then filled with different concentrations of AOF extract (0-200 mg/ml). We investigated the role of MAPK (ERK1/2, JNK and p38) pathways for AOF-induced matrix-degrading proteolytic enzyme (PAs and MMP2/9) production in RSC96 Schwann cells.

Results

The results showed that AOF increased the expressions of uPA, tPA, MMP-9, and MAPKs in vivo. In vitro, our results show that treatment with AOF extract induces ERK1/2, JNK, and p38 phosphorylation to activate the downstream PAs and MMPs signaling expression. AOF-stimulated ERK1/2, JNK, and p38 phosphorylation attenuated by individual pretreatment with siRNAs or inhibitors (U0126, SP600125 and SB203580), resulting in migration and uPA-related signal pathway inhibition.

Conclusions

Taken together our data suggests the MAPKs (ERK1/2, JNK and p38), PAs (uPA, tPA), MMP (MMP2, MMP9) regenerative and migration signaling pathway of Schwann cells regulated by AOF extract might play a major role in Schwann cell migration and damaged peripheral nerve regeneration.

Dilong: food for thought and medicine

Earthworms have several names in different countries (In Chinese: 地龍 dì lóng, Japanese: Mimizu, Korean: Jireongi, Spanish: Lombriz de tierra, French: Ver de terre, German: Regenwurm, Italian: Lombrico, Swedish: Daggmask, Portuguese: Minhoca). They have long been used as a food source as well as treatments of various ailments. Many alternative and traditional disciplines of medicine, such as those in China, Japan, and Korea, developed medicinal uses of dilong from an initial utilization as nutrition. Increased curiosity in the potential medicinal properties of dilong has come to fruition through bioprospecting and evidence based research. This increased questioning and searching spawned first from a growing knowledge base about the earthworm's innate immune system. Their importance in understanding the evolution of the innate immune system has long been overlooked because of the ecological importance in soil preservation, earthworm immune systems, being full of leukocytes and humoral products, offer significant advantages when used as medicines. Earthworms offer an unanticipated slew of potential health benefits without common drawbacks that come with other biological, alternative forms of medicine such as cost, ethical and pathological concerns of animal testing.

Origin of innate immune responses: revelation of food and medicinal applications

Much is known about the strong ecological impact that earthworms ( Qiū Yǐn; Pheretima) have on soil in terms of fertility, nutrient production, and tilling. Even more interesting though is the impact they have had on our understanding of innate immunity, and from this discovery, there has been a simultaneous recognition of their potential through their historical use as food and their use in treatment of certain chronic health problems that often afflict humans. This bifurcating growing knowledge base has stemmed from centuries of honing and practicing traditional and complementary forms of medicine such as Ayurveda (India) Traditional Chinese Medicine (China), Kampo (Japan), and Traditional Korean Medicine (Korea). Earthworms (Dilong) have also been credited as a model for research concerning the nervous and endocrine systems. One of the reasons behind the earthworm's tremendous impact on research into these biomedical endeavors is partly due to its lack of ethical restrictions, like those imposed on vertebrate models. Using invertebrate models as opposed to mice or other mammalian models bypasses ethical concerns. Moreover, financial constraints consistently hover over biological research that requires living subjects, preferably mammals. Earthworms are a rich source of several vital biological macromolecules and other nutrients. They have long been used as food in several cultures such as the Ye'Kuana in Venezuela, the Maori in New Zealand, and the nomadic populations in Papua New Guinea. Earthworms and their nutritious products have been shown to exert significant effects in treating humans for disorders of inflammation and blood coagulation. One area that continues to be examined is the earthworm's ability to regenerate lost appendages, and these effects have been extended to mammals. Evidence reveals that earthworm extracts may actually promote the regeneration of damaged nerves. This presentation will explore how earthworms may reveal significant advances and conclusions that decipher innate immunity. This is intimately associated with them as sources of their various nutritional and medicinal benefits.

Cell Cycle Analysis of Rat Schwann Cells on Chitosan Scaffolds by Flow Cytometry

The fine combination of biomaterial and essential cells determines a successful artificial graft. With high biocompatibility, chitosan is a choice of materials for regeneration medicine. In the peripheral nervous system, Schwann cells are critical for nerve regeneration. Schwann cells not only help to conduct the nerve pulse but also guide the nerve extension, especially the injured nerve for recovery. Studies showed that chitosan can be a bridge material for damaged nerve regeneration. The interactions between chitosan and Schwann cells may provide important information for designing the chitosan grafts applied in medical applications. For this purpose, the chitoson was made into conduits by lyophilization. The conduit has porous 3D scaffolds and seeded with rat Schwann cells. The harvested cells were labeled with PI fluorescent dye and analyzed with flow cytometry. The results showed that the rates of DNA replication (S-phase) and cell division (G2 phase) of the cells grew on chitosan scaffolds were higher than the ones grew on the plane substrate. This indicates that the cells grew on chitosan scaffolds were more active than those on the plane substrate in cell proliferation, and the biocompatibility of chitosan can be sustained in this quantitative analysis. Therefore, chitosan scaffolds are efficient for cell expansion of rat Schwann cells and may be beneficial for the purpose of tissue engineering. This study proves that cell cycle analysis is a new point of view in disclosing the cell-material interactions.

Effect of oral administration of Pheretima aspergillum (earthworm) in rats with cerebral infarction induced by middle-cerebral artery occlusion

We investigated the curative effect of Pheretima aspergillum (earthworm, PA) on rats with middle cerebral artery occlusion (MCAo). The MCAo-induced cerebral infarction was established and its underlying mechanisms by counting the infarction areas and evaluating the rats' neurological status. Immunostaining was used to test the expression of NeuN, and glial fibrillary acidic (GFAP), S100B, and brain-derived neurotrophic factor (BDNF) proteins. Our results showed that oral administration of PA for two weeks to rats with MCAo successfully reduced cerebral infarction areas in the cortex and striatum, and also reduced scores of neurological deficit. The PA-treated MCAo rats showed greatly decreased neuronal death, glial proliferation, and S100B proteins in the penumbra area of the cortex and in the ischemic core area of the cortex, but BDNF did not changed. These results demonstrated novel and detailed cellular mechanisms underlying the neuroprotective effects of PA in MCAo rats.

Earthworms dilong: ancient, inexpensive, noncontroversial models may help clarify approaches to integrated medicine emphasizing neuroimmune systems

Earthworms have provided ancient cultures with food and sources of medicinal cures. Ayurveda, traditional Chinese medicine (TCM), and practices in Japan, Vietnam, and Korea have focused first on earthworms as sources of food. Gradually fostering an approach to potential beneficial healing properties, there are renewed efforts through bioprospecting and evidence-based research to understand by means of rigorous investigations the mechanisms of action whether earthworms are used as food and/or as sources of potential medicinal products. Focusing on earthworms grew by serendipity from an extensive analysis of the earthworm's innate immune system. Their immune systems are replete with leukocytes and humoral products that exert credible health benefits. Their emerging functions with respect to evolution of innate immunity have long been superseded by their well-known ecological role in soil conservation. Earthworms as inexpensive, noncontroversial animal models (without ethical concerns) are not vectors of disease do not harbor parasites that threaten humans nor are they annoying pests. By recognizing their numerous ecological, environmental, and biomedical roles, substantiated by inexpensive and more comprehensive investigations, we will become more aware of their undiscovered beneficial properties.

Carboxymethylated chitosan stimulates proliferation of Schwann cells in vitro via the activation of the ERK and Akt signaling pathways

Proliferation of Schwann cell in the injured peripheral nerve supports axonal regeneration and also is critical for the regeneration of injured nerves. In this publication, carboxymethylated chitosan (CMCS) was studied to determine its capacity (i) to induce proliferation and synthesis of proliferating cell nuclear antigen (PCNA) and (ii) to activate mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK/ERK) and phosphatidylinositil-3 kinase (PI3K)/Akt signaling pathways in rat Schwann cells. CMCS was found to induce proliferation and PCNA synthesis in Schwann cells in a dose and time dependent manner. CMCS was shown to phosphorylate ERK1/2 and Akt in Schwann cell proliferation. The phosphorylation of ERK1/2 and Akt in Schwann cells was blocked by the MEK inhibitor PD98059 and the PI3K inhibitor wortmannin. In addition, inhibition of the MEK/ERK or the PI3K/Akt signaling pathways significantly decreased the proliferative effects of CMCS in Schwann cells. Overall, the above results indicate that CMCS stimulates proliferation of Schwann cells by activating the intracellular signaling cascades of ERK1/2 and PI3K/Akt.

Dilong: role in peripheral nerve regeneration

Dilong, also known as earthworm, has been widely used in traditional Chinese medicine (TCM) for thousands of years. Schwann cell migration and proliferation are critical for the regeneration of injured nerves and Schwann cells provide an essentially supportive role for neuron regeneration. However, the molecular mechanisms of migration and proliferation induced by dilongs in Schwann cells remain unclear. Here, we discuss the molecular mechanisms that includes (i) migration signaling, MAPKs (mitogen-activated protein kinases), mediated PAs and MMP2/9 pathway; (ii) survival and proliferative signaling, IGF-I (insulin-like growth factor-I)-mediated PI3K/Akt pathways and (iii) cell cycle regulation. Dilong stimulate RSC96 cell proliferation and migration. It can induce phosphorylation of ERK1/2 and p38, but not JNK, and activate the downstream signaling expression of PAs (plasminogen activators) and MMPs (matrix metalloproteinases) in a time-dependent manner. In addition, Dilong stimulated ERK1/2 and p38 phosphorylation was attenuated by pretreatment with chemical inhibitors (U0126 and SB203580), and small interfering ERK1/2 and p38 RNA, resulting in migration and uPA-related signal pathway inhibition. Dilong also induces the phosphorylation of IGF-I-mediated PI3K/Akt pathway, activates protein expression of PCNA (proliferating cell nuclear antigen) and cell cycle regulatory proteins (cyclin D1, cyclin E and cyclin A) in a time-dependent manner. In addition, it accelerates G₁-phase progression with earlier S-phase entry and significant numbers of cells entered the S-phase. The siRNA-mediated knockdown of PI3K that significantly reduces PI3K protein expression levels, resulting in Bcl₂ survival factor reduction, revealing a marked blockage of G₁ to S transition in proliferating cells. These results reveal the unknown RSC96 cell migration and proliferation mechanism induced by dilong, which find use as a new medicine for nerve regeneration.