Comparison of Immediate Neuromodulatory Effects between Focal Vibratory and Electrical Sensory Stimulations after Stroke.

Focal vibratory stimulation (FVS) and neuromuscular electrical stimulation (NMES) are promising technologies for sensory rehabilitation after stroke. However, the differences between these techniques in immediate neuromodulatory effects on the poststroke cortex are not yet fully understood. In this research, cortical responses in persons with chronic stroke (n = 15) and unimpaired controls (n = 15) were measured by whole-brain electroencephalography (EEG) when FVS and NMES at different intensities were applied transcutaneously to the forearm muscles. Both FVS and sensory-level NMES induced alpha and beta oscillations in the sensorimotor cortex after stroke, significantly exceeding baseline levels (p < 0.05). These oscillations exhibited bilateral sensory deficiency, early adaptation, and contralesional compensation compared to the control group. FVS resulted in a significantly faster P300 response (p < 0.05) and higher theta oscillation (p < 0.05) compared to NMES. The beta desynchronization over the contralesional frontal-parietal area remained during NMES (p > 0.05), but it was significantly weakened during FVS (p < 0.05) after stroke. The results indicated that both FVS and NMES effectively activated the sensorimotor cortex after stroke. However, FVS was particularly effective in eliciting transient involuntary attention, while NMES primarily fostered the cortical responses of the targeted muscles in the contralesional motor cortex.

A specific dispiropiperazine derivative that arrests cell cycle, induces apoptosis, necrosis and DNA damage.

Dispiropiperazine compounds are a class of molecules known to confer biological activity, but those that have been studied as cell cycle regulators are few in number. Here, we report the characterization and synthesis of two dispiropiperazine derivatives: the previously synthesized spiro[2',3]-bis(acenaphthene-1'-one)perhydrodipyrrolo-[1,2-a:1,2-d]-pyrazine (SPOPP-3, 1), and its previously undescribed isomer, spiro[2',5']-bis(acenaphthene-1'-one)perhydrodipyrrolo-[1,2-a:1,2-d]-pyrazine (SPOPP-5, 2). SPOPP-3 (1), but not SPOPP-5 (2), was shown to have anti-proliferative activity against a panel of 18 human cancer cell lines with IC50 values ranging from 0.63 to 13 µM. Flow cytometry analysis revealed that SPOPP-3 (1) was able to arrest cell cycle at the G2/M phase in SW480 human cancer cells. Western blot analysis further confirmed the cell cycle arrest is in the M phase. In addition, SPOPP-3 (1) was shown to induce apoptosis, necrosis, and DNA damage as well as disrupt mitotic spindle positioning in SW480 cells. These results warrant further investigation of SPOPP-3 (1) as a novel anti-cancer agent, particularly for its potential ability to sensitize cancer cells for radiation-induced cell death, enhance cancer immunotherapy, overcome apoptosis-related drug resistance and for possible use in synthetic lethality cancer treatments.

An Immunomodulatory Polysaccharide-Protein Complex Isolated from the Polypore Fungus Royoporus badius.

Many wild edible polypore mushrooms have medicinal value. In this study, we investigate the potential medicinal properties of the wild polypore mushroom Royoporus badius collected from north-central British Columbia, Canada. Water extract from R. badius was found to exhibit potent immunomodulatory activity. The extract was purified using DEAE-Sephadex anion-exchange chromatography as well as Sephacryl S-500 and HPLC BioSEC5 size-exclusion chromatography, to yield a novel polysaccharide-protein complex (IMPP-Rb).IMPP-Rb has a peak maxima molecular weight (Mp) of 950 kDa. GC-MS analyses showed that IMPP-Rb is composed predominantly of glucose (49.2%), galactose (11.3%), mannose (10.8%), rhamnose (9.6%), and galacturonic acid (8.2%), with smaller amounts of xylose (5.2%), fucose (2.8%), N-acetyl glucosamine (1.8%), and arabinose (1.2%). IMPP-Rb has multiple linkages, with 4-Glcp, 4-Manp, 6-Manp, 3,4-Manp, 4-Xylp, and 2-Rhap being the most prominent. IMPP-Rb is capable of inducing many cytokines in vitro and the protein component is indispensable for its immunomodulatory activity. IMPP-Rb has potential application as an immuno-stimulatory agent with pharmaceutical value.

An Exoneuromusculoskeleton for Self-Help Upper Limb Rehabilitation After Stroke.

This article presents a novel electromyography (EMG)-driven exoneuromusculoskeleton that integrates the neuromuscular electrical stimulation (NMES), soft pneumatic muscle, and exoskeleton techniques, for self-help upper limb training after stroke. The developed system can assist the elbow, wrist, and fingers to perform sequential arm reaching and withdrawing tasks under voluntary effort control through EMG, with a lightweight, compact, and low-power requirement design. The pressure/torque transmission properties of the designed musculoskeletons were quantified, and the assistive capability of the developed system was evaluated on patients with chronic stroke (n = 10). The designed musculoskeletons exerted sufficient mechanical torque to support joint extension for stroke survivors. Compared with the limb performance when no assistance was provided, the limb performance (measured as the range of motion in joint extension) significantly improved when mechanical torque and NMES were provided (p < 0.05). A pilot trial was conducted on patients with chronic stroke (n = 15) to investigate the feasibility of using the developed system in self-help training and the rehabilitation effects of the system. All the participants completed the self-help device-assisted training with minimal professional assistance. After a 20-session training, significant improvements were noted in the voluntary motor function and release of muscle spasticity at the elbow, wrist, and fingers, as indicated by the clinical scores (p < 0.05). The EMG parameters (p < 0.05) indicated that the muscular coordination of the entire upper limb improved significantly after training. The results suggested that the developed system can effectively support self-help upper limb rehabilitation after stroke. ClinicalTrials.gov Register Number NCT03752775.

Home-based self-help telerehabilitation of the upper limb assisted by an electromyography-driven wrist/hand exoneuromusculoskeleton after stroke.

BACKGROUND: Most stroke survivors have sustained upper limb impairment in their distal joints. An electromyography (EMG)-driven wrist/hand exoneuromusculoskeleton (WH-ENMS) was developed previously. The present study investigated the feasibility of a home-based self-help telerehabilitation program assisted by the aforementioned EMG-driven WH-ENMS and its rehabilitation effects after stroke. METHODS: Persons with chronic stroke (n = 11) were recruited in a single-group trial. The training progress, including the training frequency and duration, was telemonitored. The clinical outcomes were evaluated using the Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT), Wolf Motor Function Test (WMFT), Motor Functional Independence Measure (FIM), and Modified Ashworth Scale (MAS). Improvement in muscle coordination was investigated in terms of the EMG activation level and the Co-contraction Index (CI) of the target muscles, including the abductor pollicis brevis (APB), flexor carpi radialis-flexor digitorum (FCR-FD), extensor carpi ulnaris-extensor digitorum (ECU-ED), biceps brachii (BIC), and triceps brachii (TRI). The movement smoothness and compensatory trunk movement were evaluated in terms of the following two kinematic parameters: number of movement units (NMUs) and maximal trunk displacement (MTD). The above evaluations were conducted before and after the training. RESULTS: All of the participants completed the home-based program with an intensity of 63.0 ± 1.90 (mean ± SD) min/session and 3.73 ± 0.75 (mean ± SD) sessions/week. After the training, motor improvements in the entire upper limb were found, as indicated by the significant improvements (P < 0.05) in the FMA, ARAT, WMFT, and MAS; significant decreases (P < 0.05) in the EMG activation levels of the APB and FCR-FD; significant decreases (P < 0.05) in the CI of the ECU-ED/FCR-FD, ECU-ED/BIC, FCR-FD/APB, FCR-FD/BIC, FCR-FD/TRI, APB/BIC and BIC/TRI muscle pairs; and significant reductions (P < 0.05) in the NMUs and MTD. CONCLUSIONS: The results suggested that the home-based self-help telerehabilitation program assisted by EMG-driven WH-ENMS is feasible and effective for improving the motor function of the paretic upper limb after stroke. Trial registration ClinicalTrials.gov. NCT03752775; Date of registration: November 20, 2018.

Characterizing the interaction between insulin-like growth factor 2 mRNA-binding protein 1 (IMP1) and KRAS expression.

Insulin-like growth factor 2 mRNA-binding protein-1 (IMP1) has high affinity for KRAS mRNA, and it can regulate KRAS expression in cells. We first characterized the molecular interaction between IMP1 and KRAS mRNA. Using IMP1 variants with a point mutation in the GXXG motif at each KH domain, we showed that all KH domains play a critical role in the binding of KRAS RNA. We mapped the IMP1-binding sites on KRAS mRNA and show that IMP1 has the highest affinity for nts 1-185. Although it has lower affinity, IMP1 does bind to other coding regions and the 3'-UTR of KRAS mRNA. Eight antisense oligonucleotides (AONs) were designed against KRAS RNA in the nts 1-185 region, but only two, SM6 and SM7, show potent inhibition of the IMP1-KRAS RNA interaction in vitro To test the activity of these two AONs in SW480 human colon cancer cells, we used 2'-O-methyl-modified versions of SM6 and SM7 in an attempt to down-regulate KRAS expression. To our surprise, both SM6 and SM7 had no effect on KRAS mRNA and protein expression, but significantly inhibited IMP1 protein expression without altering IMP1 mRNA level. On the other hand, knockdown of IMP1 using siRNA lowered the expression of KRAS. Using Renilla luciferase as a reporter, we found that IMP1 translation is significantly reduced in SM7-treated cells with no change in let-7a levels. The present study shows that the regulation of KRAS expression by IMP1 is complex and may involve both the IMP1 protein and its mRNA transcript.

A Neuromuscular Electrical Stimulation (NMES) and robot hybrid system for multi-joint coordinated upper limb rehabilitation after stroke.

BACKGROUND: It is a challenge to reduce the muscular discoordination in the paretic upper limb after stroke in the traditional rehabilitation programs. METHOD: In this study, a neuromuscular electrical stimulation (NMES) and robot hybrid system was developed for multi-joint coordinated upper limb physical training. The system could assist the elbow, wrist and fingers to conduct arm reaching out, hand opening/grasping and arm withdrawing by tracking an indicative moving cursor on the screen of a computer, with the support from the joint motors and electrical stimulations on target muscles, under the voluntary intention control by electromyography (EMG). Subjects with chronic stroke (n = 11) were recruited for the investigation on the assistive capability of the NMES-robot and the evaluation of the rehabilitation effectiveness through a 20-session device assisted upper limb training. RESULTS: In the evaluation, the movement accuracy measured by the root mean squared error (RMSE) during the tracking was significantly improved with the support from both the robot and NMES, in comparison with those without the assistance from the system (P < 0.05). The intra-joint and inter-joint muscular co-contractions measured by EMG were significantly released when the NMES was applied to the agonist muscles in the different phases of the limb motion (P < 0.05). After the physical training, significant improvements (P < 0.05) were captured by the clinical scores, i.e., Modified Ashworth Score (MAS, the elbow and the wrist), Fugl-Meyer Assessment (FMA), Action Research Arm Test (ARAT), and Wolf Motor Function Test (WMFT). CONCLUSIONS: The EMG-driven NMES-robotic system could improve the muscular coordination at the elbow, wrist and fingers. TRIAL REGISTRATION: ClinicalTrials.gov. NCT02117089 ; date of registration: April 10, 2014.

The Effects of Upper-Limb Training Assisted with an Electromyography-Driven Neuromuscular Electrical Stimulation Robotic Hand on Chronic Stroke.

BACKGROUND: Impaired hand dexterity is a major disability of the upper limb after stroke. An electromyography (EMG)-driven neuromuscular electrical stimulation (NMES) robotic hand was designed previously, whereas its rehabilitation effects were not investigated. OBJECTIVES: This study aims to investigate the rehabilitation effectiveness of the EMG-driven NMES-robotic hand-assisted upper-limb training on persons with chronic stroke. METHOD: A clinical trial with single-group design was conducted on chronic stroke participants (n = 15) who received 20 sessions of EMG-driven NMES-robotic hand-assisted upper-limb training. The training effects were evaluated by pretraining, posttraining, and 3-month follow-up assessments with the clinical scores of the Fugl-Meyer Assessment (FMA), the Action Research Arm Test (ARAT), the Wolf Motor Function Test, the Motor Functional Independence Measure, and the Modified Ashworth Scale (MAS). Improvements in the muscle coordination across the sessions were investigated by EMG parameters, including EMG activation level and Co-contraction Indexes (CIs) of the target muscles in the upper limb. RESULTS: Significant improvements in the FMA shoulder/elbow and wrist/hand scores (P < 0.05), the ARAT (P < 0.05), and in the MAS (P < 0.05) were observed after the training and sustained 3 months later. The EMG parameters indicated a significant decrease of the muscle activation level in flexor digitorum (FD) and biceps brachii (P < 0.05), as well as a significant reduction of CIs in the muscle pairs of FD and triceps brachii and biceps brachii and triceps brachii (P < 0.05). CONCLUSION: The upper-limb training integrated with the assistance from the EMG-driven NMES-robotic hand is effective for the improvements of the voluntary motor functions and the muscle coordination in the proximal and distal joints. Furthermore, the motor improvement after the training could be maintained till 3 months later. TRIAL REGISTRATION: ClinicalTrials.gov. NCT02117089; date of registration: April 10, 2014.

Human apurinic/apyrimidinic endonuclease 1 (APE1) has 3' RNA phosphatase and 3' exoribonuclease activities.

Apurinic/apyrimidinic endonuclease 1 (APE1) is the predominant mammalian enzyme in DNA base excision repair pathway that cleaves the DNA backbone immediately 5' to abasic sites. In addition to its abasic endonuclease activity, APE1 has 3' phosphatase and 3'-5' exonuclease activities against DNA. We recently identified APE1 as an endoribonuclease that preferentially cleaves at UA, UG, and CA sites in single-stranded regions of RNAs and can regulate c-myc mRNA level and half-life in cells. APE1 can also endonucleolytically cleave abasic single-stranded RNA. Here, we show for the first time that the human APE1 has 3' RNA phosphatase and 3' exoribonuclease activities. Using three distinct RNA substrates, we show that APE1, but not RNase A, can remove the phosphoryl group from the 3' end of RNA decay products. Studies using various site-directed APE1 mutant proteins (H309N, H309S, D283N, N68A, D210N, Y171F, D308A, F266A, and D70A) suggest that the 3' RNA phosphatase activity shares the same active center as its other known nuclease activities. A number of APE1 variants previously identified in the human population, including the most common D148E variant, have greater than 80% reduction in the 3' RNA phosphatase activity. APE1 can remove a ribonucleotide from the 3' overhang of RNA decay product, but its 3'-5' exoribonuclease activity against unstructured poly(A), poly(C), and poly(U) RNAs is relatively weak. This study further underscores the significance of understanding the role of APE1 in RNA metabolism in vivo.

Molecular insights into the coding region determinant-binding protein-RNA interaction through site-directed mutagenesis in the heterogeneous nuclear ribonucleoprotein-K-homology domains.

The ability of its four heterogeneous nuclear RNP-K-homology (KH) domains to physically associate with oncogenic mRNAs is a major criterion for the function of the coding region determinant-binding protein (CRD-BP). However, the particular RNA-binding role of each of the KH domains remains largely unresolved. Here, we mutated the first glycine to an aspartate in the universally conserved GXXG motif of the KH domain as an approach to investigate their role. Our results show that mutation of a single GXXG motif generally had no effect on binding, but the mutation in any two KH domains, with the exception of the combination of KH3 and KH4 domains, completely abrogated RNA binding in vitro and significantly retarded granule formation in zebrafish embryos, suggesting that any combination of at least two KH domains cooperate in tandem to bind RNA efficiently. Interestingly, we found that any single point mutation in one of the four KH domains significantly impacted CRD-BP binding to mRNAs in HeLa cells, suggesting that the dynamics of the CRD-BP-mRNA interaction vary over time in vivo. Furthermore, our results suggest that different mRNAs bind preferentially to distinct CRD-BP KH domains. The novel insights revealed in this study have important implications on the understanding of the oncogenic mechanism of CRD-BP as well as in the future design of inhibitors against CRD-BP function.

Altered endoribonuclease activity of apurinic/apyrimidinic endonuclease 1 variants identified in the human population.

Apurinic/apyrimidinic endonuclease 1 (APE1) is the major mammalian enzyme in the DNA base excision repair pathway and cleaves the DNA phosphodiester backbone immediately 5' to abasic sites. APE1 also has 3'-5' DNA exonuclease and 3' DNA phosphodiesterase activities, and regulates transcription factor DNA binding through its redox regulatory function. The human APE1 has recently been shown to endonucleolytically cleave single-stranded regions of RNA. Towards understanding the biological significance of the endoribonuclease activity of APE1, we examined eight different amino acid substitution variants of APE1 previously identified in the human population. Our study shows that six APE1 variants, D148E, Q51H, I64V, G241R, R237A, and G306A, exhibit a 76-85% reduction in endoribonuclease activity against a specific coding region of the c-myc RNA, yet fully retain the ability to cleave apurinic/apyrimidinic DNA. We found that two APE1 variants, L104R and E126D, exhibit a unique RNase inhibitor-resistant endoribonuclease activity, where the proteins cleave c-myc RNA 3' of specific single-stranded guanosine residues. Expression of L104R and E126D APE1 variants in bacterial Origami cells leads to a 60-80% reduction in colony formation and a 1.5-fold increase in cell doubling time, whereas the other variants, which exhibit diminished endoribonuclease activity, had no effect. These data indicate that two human APE1 variants exhibit a unique endoribonuclease activity, which correlates with their ability to induce cytotoxicity or slow down growth in bacterial cells and supports the notion of their biological functionality.