Neuromuscular implants: Interfacing with skeletal muscle for improved clinical translation of prosthetic limbs.

After an amputation, advanced prosthetic limbs can be used to interface with the nervous system and restore motor function. Despite numerous breakthroughs in the field, many of the recent research advancements have not been widely integrated into clinical practice. This review highlights recent innovations in neuromuscular implants-specifically those that interface with skeletal muscle-which could improve the clinical translation of prosthetic technologies. Skeletal muscle provides a physiologic gateway to harness and amplify signals from the nervous system. Recent surgical advancements in muscle reinnervation surgeries leverage the "bio-amplification" capabilities of muscle, enabling more intuitive control over a greater number of degrees of freedom in prosthetic limbs than previously achieved. We anticipate that state-of-the-art implantable neuromuscular interfaces that integrate well with skeletal muscle and novel surgical interventions will provide a long-term solution for controlling advanced prostheses. Flexible electrodes are expected to play a crucial role in reducing foreign body responses and improving the longevity of the interface. Additionally, innovations in device miniaturization and ongoing exploration of shape memory polymers could simplify surgical procedures for implanting such interfaces. Once implanted, wireless strategies for powering and transferring data from the interface can eliminate bulky external wires, reduce infection risk, and enhance day-to-day usability. By outlining the current limitations of neuromuscular interfaces along with potential future directions, this review aims to guide continued research efforts and future collaborations between engineers and specialists in the field of neuromuscular and musculoskeletal medicine.

Two-Dimensional Nanofibrous Networks by Superspreading-Based Phase Inversion for High-Efficiency Separation.

Two-dimensional (2D) nanomaterials have been widely applied as building blocks of nanoporous materials for high-precision separations. However, most existing 2D nanomaterials suffer from poor continuity and a lack of interior linking, resulting in deteriorated performance when assembled into macroscopic bulk structures. Here, a unique superspreading-based phase inversion technique is proposed to directly construct 2D nanofibrous networks (NFNs) from a polymer solution. By tailoring capillary behavior, polymer solution droplets evolve into ultrathin liquid films through superspreading; manipulating phase instability, subsequently, enables the liquid film to phase invert into continuous nanostructured networks. The assembled single-layered NFNs possess integrated structural superiorities of 1D nanoscale fiber diameter (∼40 nm) and 2D lateral infinity, exhibiting a weblike nanoarchitecture with extremely small through-pores (∼100 nm). Our NFNs show remarkable performances in air filtration (PM0.3 removal) and water purification (microfiltration level). This creation of such attractive 2D fibrous nanomaterials can pave the way for versatile high-performance separation applications.

Discovery of a highly potent NPAS3 heterodimer inhibitor by covalently modifying ARNT.

Neuronal PAS domain protein 3 (NPAS3), a basic helix-loop-helix PER-ARNT-SIM (bHLH-PAS) family member, is a pivotal transcription factor in neuronal regeneration, development, and related diseases, regulating the expression of downstream genes. Despite several modulators of certain bHLH-PAS family proteins being identified, the NPAS3-targeted compound has yet to be reported. Herein, we discovered a hit compound BI-78D3 that directly blocks the NPAS3-ARNT heterodimer formation by covalently binding to the aryl hydrocarbon receptor nuclear translocator (ARNT) subunit. Further optimization based on the hit scaffold yielded a highly potent Compound 6 with a biochemical EC50 value of 282 ± 61 nM and uncovered the 5-nitrothiazole-2-sulfydryl as a cysteine-targeting covalent warhead. Compound 6 effectively down-regulated NPAS3's transcriptional function by disrupting the interface of NPAS3-ARNT complexes at cellular level. In conclusion, our study identifies the 5-nitrothiazole-2-sulfydryl as a cysteine-modified warhead and provides a strategy that blocks the NPAS3-ARNT heterodimerization by covalently conjugating ARNT Cys336 residue. Compound 6 may serve as a promising chemical probe for exploring NPAS3-related physiological functions.

Impacts of dibutyl phthalate on bacterial community composition and carbon and nitrogen metabolic pathways in a municipal wastewater treatment system.

Dibutyl phthalate (DBP) is a typical toxic and hazardous pollutant in pharmaceutical wastewater, affecting the metabolism of microbial flora, leading to decreased treatment efficiency, and deteriorated effluent quality in municipal wastewater treatment plants (WWTPs). This study conducted a long-term experiment with 6 operational stages in a pilot-scale A2O-MBR system, analyzing the effect of DBP on the bacterial community and their carbon and nitrogen metabolic pathways. 16S rRNA gene amplicon sequencing analysis and principal components analysis (PCA) showed that DBP at 8 mg/L significantly influenced the structure of bacterial community (P < 0.05), resulting in reduced bacterial community diversity. Metagenomic analysis was used to explore the embedded carbon and nitrogen metabolic pathways. At the presence of DBP, the metabolism of saccharides, lipids, and aromatic compounds were blocked owing to the vanishment of key enzyme (such as acetylaminohexosyltransferase (EC 2.4.1.92) and UDP-sugar pyro phosphorylase (EC 2.7.7.64)) encoding genes, resulting in weakened carbon metabolism, and thus reduced COD removal performance. The resultant deficiency of the genes such as those encoding hydroxyproline dehydrogenase (EC 1.5.5.3) gave rise to interrupted metabolic pathways of amino acid (arginine, proline, tyrosine, and tryptophan), resulting in declined function of nitrogen metabolism and thus reduced TN removal efficiency. The uncovery of the mechanisms by which DBP affects wastewater treatment system efficiency and microbial metabolism is of theoretical importance for the efficient operation of municipal and pharmaceutical wastewater treatment systems.

Discovery of novel USP8 inhibitors via Ubiquitin-Rho-110 fluorometric assay based high throughput screening.

USP8, one member of deubiquitinating enzymes (DUBs) families, maintains the ubiquitination level of EGFR and regulates the downstream signaling pathways. The deregulation of USP8 has been implicated in many human diseases, especially in cancer. Therefore, USP8 has been identified as a promising target for drug design. Herein, via high throughput screening based on Ubiquitin-rhodamine-110 (Ubiquitin-Rho-110) fluorometric activity assay, we discovered a novel inhibitor DC-U43. By structure optimization, DC-U43-10 reached a half-maximal inhibitory concentration (IC50) value of 2.6 ± 1.1 µM and exhibited 10-fold selectivity against USP7. The binding between DC-U43-10 and USP8 was validated by surface plasmon resonance (SPR) assay with a KD value of 10.5 ± 3.7 µM. It also inhibited the colony formation of H1975 cells. Hence, DC-U43-10 represents a kind of USP8 inhibitors with novel scaffold and has broad prospects for being a probe for USP8-related academic and clinical research.

Drug development and potential targets for Cushing's syndrome.

Cushing's syndrome (CS) is a complex disorder characterized by the excessive secretion of cortisol, with Cushing's disease (CD), particularly associated with pituitary tumors, exhibiting heightened morbidity and mortality. Although transsphenoidal pituitary surgery (TSS) stands as the primary treatment for CD, there is a crucial need to optimize patient prognosis. Current medical therapy serves as an adjunctive measure due to its unsatisfactory efficacy and unpredictable side effects. In this comprehensive review, we delve into recent advances in understanding the pathogenesis of CS and explore therapeutic options by conducting a critical analysis of potential drug targets and candidates. Additionally, we provide an overview of the design strategy employed in previously reported candidates, along with a summary of structure-activity relationship (SAR) analyses and their biological efficacy. This review aims to contribute valuable insights to the evolving landscape of CS research, shedding light on potential avenues for therapeutic development.

Merging Humans and Neuroprosthetics through Regenerative Peripheral Nerve Interfaces.

Limb amputations can be devastating and significantly affect an individual's independence, leading to functional and psychosocial challenges in nearly 2 million people in the United States alone. Over the past decade, robotic devices driven by neural signals such as neuroprostheses have shown great potential to restore the lost function of limbs, allowing amputees to regain movement and sensation. However, current neuroprosthetic interfaces have challenges in both signal quality and long-term stability. To overcome these limitations and work toward creating bionic limbs, the Neuromuscular Laboratory at University of Michigan Plastic Surgery has developed the Regenerative Peripheral Nerve Interface (RPNI). This surgical construct embeds a transected peripheral nerve into a free muscle graft, effectively amplifying small peripheral nerve signals to provide enhanced control signals for a neuroprosthetic limb. Furthermore, the RPNI has the potential to provide sensory feedback to the user and facilitate neuroprosthesis embodiment. This review focuses on the animal studies and clinical trials of the RPNI to recapitulate the promising trajectory toward neurobionics where the boundary between an artificial device and the human body becomes indistinct. This paper also sheds light on the prospects of the improvement and dissemination of the RPNI technology.

The discovery of potent USP2/USP8 dual-target inhibitors for the treatment of breast cancer via structure guided optimization of ML364.

USP2 and USP8 are crucial in the development and progression of breast cancer, primarily through the stabilization of protein substrates such as Her2 and ERα. The dual-target inhibitor ML364, targeting both USP2 and USP8, has garnered significant interest in recent research. In this study, we developed a series of ML364 derivatives using ligand-based drug design strategies. The standout compound, LLK203, demonstrated enhanced inhibitory activity, showing a 4-fold increase against USP2 and a 9-fold increase against USP8, compared to the parent molecule. In MCF-7 breast cancer cells, LLK203 effectively degraded key proteins involved in cancer progression and notably inhibited cell proliferation. Moreover, LLK203 exhibited potent in vivo efficacy in the 4T1 homograft model, while maintaining a low toxicity profile. These results underscore the potential of LLK203 as a promising dual-target inhibitor of USP2/USP8 for breast cancer treatment.

Direct Synthesis of Polyimide Curly Nanofibrous Aerogels for High-Performance Thermal Insulation Under Extreme Temperature.

Maintaining human body temperature is one of the basic needs for living, which requires high-performance thermal insulation materials to prevent heat exchange with external environment. However, the most widely used fibrous thermal insulation materials always suffer from the heavy weight, weak mechanical property, and moderate capacity to suppress heat transfer, resulting in limited personal cold and thermal protection performance. Here, an ultralight, mechanically robust, and thermally insulating polyimide (PI) aerogel is directly synthesized via constructing 3D interlocked curly nanofibrous networks during electrospinning. Controlling the solution/water molecule interaction enables the rapid phase inversion of charged jets, while the multiple jets are ejected by regulating charge density of the fluids, thus synergistically allowing numerous curly nanofibers to interlock and cross-link with each other to form porous aerogel structure. The resulted PI aerogel integrates the ultralight property with density of 2.4 mg cm-3, extreme temperature tolerance (mechanical robustness over -196 to 300 °C), and thermal insulation performance with ultralow thermal conductivity of 22.4 mW m-1 K-1, providing an ideal candidate to keep human thermal comfort under extreme temperature. This work can provide a source of inspiration for the design and development of nanofibrous aerogels for various applications.

Ultrathin Aerogel Micro/Nanofiber Membranes with Hierarchical Cellular Architecture for High-Performance Warmth Retention.

A low temperature environment poses significant challenges to the global economy and public health. However, the existing cold-protective materials still struggle with the trade-off between thickness and thermal resistance, resulting in poor thermal-wet comfort and limited personal cold protection performance. Here, a scalable strategy, based on electrospinning and solution casting, is developed to create aerogel micro/nanofiber membranes with a hierarchical cellular architecture by manipulating the phase separation of the charged jets and of the spreading casting solution. The integration of interconnected nanopores (30-60 nm), ultrafine fiber diameter, and high porosity, enables the aerogel micro/nanofiber membranes with lightweight, ultrathin thickness (∼0.5 mm), and superior warmth retention performance with ultralow thermal conductivity of 14.01 mW m-1 K-1. And the resultant membrane with customized semiclosed walls exhibits both striking wind resistance and satisfactory thermal-wet comfort (3.4 °C warmer than the cutting-edge thermal underwear). This work will inspire the design and development of high-performance fibrous materials for thermal management applications.

Design and optimization of selective and potent CDK9 inhibitors with flavonoid scaffold for the treatment of acute myeloid leukemia.

Acute myeloid leukemia (AML) is a prevalent hematological tumor associated with a high morbidity and mortality rate. CDK9, functioning as a pivotal transcriptional regulator, facilitates transcriptional elongation through phosphorylation of RNA polymerase II, which further governs the protein levels of Mcl-1 and c-Myc. Therefore, CDK9 has been considered as a promising therapeutic target for AML treatment. Here, we present the design, synthesis, and evaluation of CDK9 inhibitors bearing a flavonoid scaffold. Among them, compound 21a emerged as a highly selective CDK9 inhibitor (IC50 = 6.7 nM), exhibiting over 80-fold selectivity towards most other CDK family members and high kinase selectivity. In Mv4-11 cells, 21a effectively hindered cell proliferation (IC50 = 60 nM) and induced apoptosis by down-regulating Mcl-1 and c-Myc. Notably, 21a demonstrated significant inhibition of tumor growth in the Mv4-11 xenograft tumor model. These findings indicate that compound 21a holds promise as a potential candidate for treating AML.

Impacts of dibutyl phthalate on biological municipal wastewater treatment in a pilot-scale A2/O-MBR system.

Dibutyl phthalate (DBP) is a typical contaminant in pharmaceutical wastewater with strong bio-depressive properties which potentially affects the operation of municipal wastewater treatment systems. Based on a year-round monitoring of the quality of influent and effluent of a full-scale pharmaceutical wastewater treatment plant in Northeast China, the DBP was found to be the representative pollutant and its concentration in the effluent ranged 4.28 ± 0.93 mg/L. In this study, the negative effects of DBP on a pilot-scale A2/O-MBR system was investigated. When the influent DBP concentration reached 8.0 mg/L, the removals of chemical oxygen demand (COD) and total nitrogen (TN) were significantly inhabited (P < 0.01), with the effluent concentration of 54.7 ± 2.6 mg/L and 22.8 ± 3.7 mg/L, respectively. The analysis of pollutant removal characteristics of each process unit showed that DBP had the most significant effects on the removals of COD and TN in the anoxic tank. The α- and ß-diversity in the system decreased significantly when the influent DBP concentration reached 8.0 mg/L. The impacts of DBP on known nitrifying bacteria, such as Nitrospira, and phosphorus accumulating organisms (PAOs), such as Cadidatus Accumulibacter, were not remarkable. Whereas, DBP negatively affected the proliferation of key denitrifying bacteria, represented by Simplicispira, Dechloromonas and Acinetobacter. This study systematically revealed the impacts of DBP on the pollutants removal performance and the bacterial community structure of the biological municipal wastewater treatment process, which would provide insights for understanding the potential impacts of residues in treated pharmaceutical wastewater on biological municipal wastewater treatment.

Discovery of Potent Small-Molecule USP8 Inhibitors for the Treatment of Breast Cancer through Regulating ERα Expression.

Ubiquitin-specific protease 8 (USP8), belonging to the deubiquitinase family, has been implicated to be closely related to the occurrence of many malignant tumors, but only a few USP8-targeting inhibitors have been reported to date. In this study, we present virtual screening to discover novel hit candidates that inhibit the catalytic activity of USP8. Exploration of the structure-activity relationship led to the identification of compound DC-U4106, which binds to USP8 with a KD value of 4.7 µM and is selective over USP2 and USP7. Western blotting and immunoprecipitation showed that DC-U4106 could target the ubiquitin pathway and facilitate the degradation of ERα. In a xenograft tumor model, DC-U4106 also significantly inhibited tumor growth with minimal toxicity. Overall, our findings suggest that DC-U4106 is a promising drug candidate and targeting the USP8-ERα complex could be a new approach to treat ER-positive or drug-resistant breast cancer.

Overview of the development of selective androgen receptor modulators (SARMs) as pharmacological treatment for osteoporosis (1998-2021).

Osteoporosis is a common disease in which the risk of fracture increases due to decreased bone mass and qualitative skeletal changes. Selective androgen receptor modulators (SARMs) are agonists with tissue selectivity, which act as partial or weak androgen receptor (AR) agonists in androgenic tissues, but mainly as complete AR agonists in synthetic metabolic tissues. In the recent 20 years, many scaffolds of SARMs have been reported, among which several molecules are promising and are undergoing clinical trial evaluation. However, it is still a challenge to discover SARMs with high activity and reduced side effects. In this review, not only are structure of SARMs reported in the literatures systematically collected and classified but also the structure-activity relationships (SAR) are systematically summarized. Furthermore, the advances in SARMs as potential treatment for osteoporosis are also updated.

Carbon uptake bioenergetics of PAOs and GAOs in full-scale enhanced biological phosphorus removal systems.

This work analyzed, for the first time, the bioenergetics of PAOs and GAOs in full-scale wastewater treatment plants (WWTPs) for the uptake of different carbon sources. Fifteen samples were collected from five full-scale WWTPs. Predominance of different PAOs, i.e., Ca. Accumulibacter (0.00-0.49%), Tetrasphaera (0.37-3.94%), Microlunatus phosphovorus (0.01-0.18%), etc., and GAOs, i.e., Ca. Competibacter (0.08-5.39%), Defluviicoccus (0.05-5.34%), Micropruina (0.17-1.87%), etc., were shown by 16S rRNA gene amplicon sequencing. Despite the distinct PAO/GAO community compositions in different samples, proton motive force (PMF) was found as the key driving force (up to 90.1%) for the uptake of volatile fatty acids (VFAs, acetate and propionate) and amino acids (glutamate and aspartate) by both GAOs and PAOs at the community level, contrasting the previous understanding that Defluviicoccus have a low demand of PMF for acetate uptake. For the uptake of acetate or propionate, PAOs rarely activated F1, F0- ATPase (< 11.7%) or fumarate reductase (< 5.3%) for PMF generation; whereas, intensive involvements of these two pathways (up to 49.2% and 61.0%, respectively) were observed for GAOs, highlighting a major and community-level difference in their VFA uptake biogenetics in full-scale systems. However, different from VFAs, the uptake of glutamate and aspartate by both PAOs and GAOs commonly involved fumarate reductase and F1, F0-ATPase activities. Apart from these major and community-level differences, high level fine-scale micro-diversity in carbon uptake bioenergetics was observed within PAO and GAO lineages, probably resulting from their versatilities in employing different pathways for reducing power generation. Ca. Accumulibacter and Halomonas seemed to show higher dependency on the reverse operation of F1, F0-ATPase than other PAOs, likely due to the low involvement of glyoxylate shunt pathway. Unlike Tetrasphaera, but similar to Ca. Accumulibacter, Microlunatus phosphovorus took up glutamate and aspartate via the proton/glutamate-aspartate symporter driven by PMF. This feature was testified using a pure culture of Microlunatus phosphovorus stain NM-1. The major difference between PAOs and GAOs highlights the potential to selectively suppress GAOs for community regulation in EBPR systems. The finer-scale carbon uptake bioenergetics of PAOs or GAOs from different lineages benefits in understanding their interactions in community assembly in complex environment.

Modular derivation of diverse, regionally discrete human posterior CNS neurons enables discovery of transcriptomic patterns.

Our inability to derive the neuronal diversity that comprises the posterior central nervous system (pCNS) using human pluripotent stem cells (hPSCs) poses an impediment to understanding human neurodevelopment and disease in the hindbrain and spinal cord. Here, we establish a modular, monolayer differentiation paradigm that recapitulates both rostrocaudal (R/C) and dorsoventral (D/V) patterning, enabling derivation of diverse pCNS neurons with discrete regional specificity. First, neuromesodermal progenitors (NMPs) with discrete HOX profiles are converted to pCNS progenitors (pCNSPs). Then, by tuning D/V signaling, pCNSPs are directed to locomotor or somatosensory neurons. Expansive single-cell RNA-sequencing (scRNA-seq) analysis coupled with a novel computational pipeline allowed us to detect hundreds of transcriptional markers within region-specific phenotypes, enabling discovery of gene expression patterns across R/C and D/V developmental axes. These findings highlight the potential of these resources to advance a mechanistic understanding of pCNS development, enhance in vitro models, and inform therapeutic strategies.

Glycine adversely affects enhanced biological phosphorus removal.

Enhanced biological phosphorus removal (EBPR) is used extensively in full-scale wastewater treatment plants for the removal of phosphorus. Despite previous evidence showing that glycine is a carbon source for a certain lineage of polyphosphate accumulating organisms (PAOs) such as Tetrasphaera, it is still unknown whether glycine can support EBPR. We observed an overall adverse effect of glycine on EBPR using activated sludge from both full-scale wastewater treatment plants and lab-scale reactors harboring distant and diverse PAOs and glycogen accumulating organisms (GAOs), including Candidatus Accumulibacter, Thiothrix, Tetrasphaera, Dechloromonas, Ca. Competibacter, and Defluviicoccus, among others. Glycine induced phosphorus (P) release under anaerobic conditions without being effectively taken up by cells. The induced P release rate correlated with glycine concentration in the range of 10 to 50 mg C/L. PAOs continued to release P in the presence of glycine under aerobic conditions without any evident P uptake. Under mixed carbon conditions, the occurrence of glycine did not seem to affect acetate uptake; however, it significantly reduced the rate of P uptake in the aerobic phase. Overall, glycine did not appear to be an effective carbon source for a majority of PAOs and GAOs in full-scale and lab-scale systems, and neither did other community members utilize glycine under anaerobic or aerobic conditions. Metatranscriptomic analysis showed the transcription of glycine cleavage T, P and H protein genes, but not of the L protein or the downstream genes in the glycine cleavage pathway, suggesting barriers to metabolizing glycine. The high transcription of a gene encoding a drug/metabolite transporter suggests a potential efflux mechanism, where glycine transported into the cells is in turn exported at the expense of ATP, resulting in P release without affecting the glycine concentration in solution. The ability of glycine to induce P release without cellular uptake suggests a way to effectively recover P from P-enriched waste sludge.

Superelastic and Fire-Retardant Nano-/Microfibrous Sponges for High-Efficiency Warmth Retention.

Warmth retention equipment for personal cold protection is highly demanded in freezing weather; however, most present warmth retention materials suffer from high thermal conductivity, weak mechanical properties, and strong flammability, resulting in serious security risks. Herein, we report a facile strategy to fabricate nano-/microfibrous sponges with superelasticity, robust flame retardation, and effective warmth retention performance via direct electrospinning. The three-dimensional fluffy sponges with low volume density and high porosity are constructed by accurately regulating the relative humidity; meanwhile, the mechanically robust polyamide-imide nanofibers with high limit oxygen index (LOI) are innovatively introduced to improve the structural stability and flammability of the nano-/microfibrous sponges. Strikingly, the developed nano-/microfibrous sponges exhibit ultralight characteristics (6.9 mg cm-3), superelasticity (∼0% plastic deformation after 100 compression tests), effective flame retardant with LOI of 26.2%, and good heat preservation ability (thermal conductivity of 24.6 mW m-1 K-1). This work may shed light on designing superelastic and flame-retardant warmth retention materials for various applications.

Recent Developments in the Biology and Medicinal Chemistry of CDK9 Inhibitors: An Update.

Cyclin-dependent kinase 9 (CDK9), which regulates transcriptional elongation, is an attractive therapeutic target for many cancers, especially for cancers driven by transcriptional dysregulation. In particular, CDK9 promotes RNA polymerase II pause/release, a rate-limiting step in normal transcriptional regulation that is frequently dysregulated in cancers. Emerging evidence indicates that selective CDK9 inhibition or degradation may provide a therapeutic benefit against certain cancers. Indeed, the development of CDK9 modulators (inhibitors and degraders) has attracted great attention, with several molecules currently under clinical development. This review provides an overview of recent advances in CDK9 modulators in general, with special emphasis on compounds under clinical evaluation and new emerging strategies, such as proteolysis targeting chimeras (PROTACs).