CoCrMo nanoparticle induces neurotoxicity mediated via mitochondrial dysfunction: a study model for implant derived nanoparticle effects.

Toxicity associated with elevated levels of cobalt-chromium-molybdenum (CoCrMo) nanoparticles in total hip replacement (THR) patients has been a rising concern. Recent investigations demonstrated that these particles can induce polyneuropathy in THR patients. The current study aims to address a detailed molecular investigation of CoCrMo nanoparticle-mediated mitochondrial dynamics using induced pluripotent stem cell-derived neurons (iPSC neurons).

Liver-X-receptor agonists rescue axonal degeneration in SPG11-deficient neurons via regulating cholesterol trafficking.

Spastic paraplegia type 11 (SPG11) is a common autosomal recessive form of hereditary spastic paraplegia (HSP) characterized by the degeneration of cortical motor neuron axons, leading to muscle spasticity and weakness. Impaired lipid trafficking is an emerging pathology in neurodegenerative diseases including SPG11, though its role in axonal degeneration of human SPG11 neurons remains unknown. Here, we established a pluripotent stem cell-based SPG11 model by knocking down the SPG11 gene in human embryonic stem cells (hESCs).

Chenodeoxycholic acid rescues axonal degeneration in induced pluripotent stem cell-derived neurons from spastic paraplegia type 5 and cerebrotendinous xanthomatosis patients.

Background: Biallelic mutations in CYP27A1 and CYP7B1, two critical genes regulating cholesterol and bile acid metabolism, cause cerebrotendinous xanthomatosis (CTX) and hereditary spastic paraplegia type 5 (SPG5), respectively. These rare diseases are characterized by progressive degeneration of corticospinal motor neuron axons, yet the underlying pathogenic mechanisms and strategies to mitigate axonal degeneration remain elusive.

Methods: To generate induced pluripotent stem cell (iPSC)-based models for CTX and SPG5, we reprogrammed patient skin fibroblasts into iPSCs by transducing fibroblast cells with episomal vectors containing pluripotency factors.

Inhibiting mitochondrial fission rescues degeneration in hereditary spastic paraplegia neurons.

Hereditary spastic paraplegias are characterized by lower limb spasticity resulting from degeneration of long corticospinal axons. SPG11 is one of the most common autosomal recessive hereditary spastic paraplegias, and the SPG11 protein spatacsin forms a complex with the SPG15 protein spastizin and heterotetrameric AP5 adaptor protein complex, which includes the SPG48 protein AP5Z1. Using the integration-free episomal method, we established SPG11 patient-specific induced pluripotent stem cells (iPSCs) from patient fibroblasts.

MFN2 Deficiency Impairs Mitochondrial Transport and Downregulates Motor Protein Expression in Human Spinal Motor Neurons.

Charcot-Marie-Tooth (CMT) disease is one of the most common genetically inherited neurological disorders and CMT type 2A (CMT 2A) is caused by dominant mutations in the mitofusin-2 () gene. MFN2 is located in the outer mitochondrial membrane and is a mediator of mitochondrial fusion, with an essential role in maintaining normal neuronal functions. Although loss of MFN2 induces axonal neuropathy, the detailed mechanism by which MFN2 deficiency results in axonal degeneration of human spinal motor neurons remains largely unknown.

Monitoring Axonal Degeneration in Human Pluripotent Stem Cell Models of Hereditary Spastic Paraplegias.

Axonal degeneration underlies many debilitating diseases including hereditary spastic paraplegias (HSPs). HSPs are a large heterogeneous group of neurodegenerative diseases characterized by axonopathy involving the long corticospinal tract. How axons of these cortical projection neurons specifically degenerate in HSPs remains largely unclear partially due to the lack of human models to monitor the dynamic process of axonal degeneration.

Impaired lipid metabolism in astrocytes underlies degeneration of cortical projection neurons in hereditary spastic paraplegia.

Hereditary spastic paraplegias (HSPs) are caused by a length-dependent axonopathy of long corticospinal neurons, but how axons of these cortical projection neurons (PNs) degenerate remains elusive. We generated isogenic human pluripotent stem cell (hPSC) lines for two ATL1 missense mutations associated with SPG3A, the most common early-onset autosomal dominant HSP. In hPSC-derived cortical PNs, ATL1 mutations resulted in reduced axonal outgrowth, impaired axonal transport, and accumulated axonal swellings, recapitulating disease-specific phenotypes.

Analyzing Mitochondrial Transport and Morphology in Human Induced Pluripotent Stem Cell-Derived Neurons in Hereditary Spastic Paraplegia.

Neurons have intense demands for high energy in order to support their functions. Impaired mitochondrial transport along axons has been observed in human neurons, which may contribute to neurodegeneration in various disease states. Although it is challenging to examine mitochondrial dynamics in live human nerves, such paradigms are critical for studying the role of mitochondria in neurodegeneration.

AAV9 Vector: a Novel modality in gene therapy for spinal muscular atrophy.

Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, is characterized by the deterioration of alpha motor neurons in the brainstem and spinal cord. Currently, there is no cure for SMA, which calls for an urgent need to explore affordable and effective therapies and to maximize patients' independence and quality of life. Adeno-associated virus (AAV) vector, one of the most promising and well-investigated vehicles for delivering transgenes, is a compelling candidate for gene therapy.

Drug screening with human SMN2 reporter identifies SMN protein stabilizers to correct SMA pathology.

Spinal muscular atrophy (SMA), the leading genetic cause of infant mortality, is caused by reduced levels of functional survival motor neuron (SMN) protein. To identify therapeutic agents for SMA, we established a versatile SMN2-GFP reporter line by targeting the human gene. We then screened a compound library and identified Z-FA-FMK as a potent candidate.

Rescue axonal defects by targeting mitochondrial dynamics in hereditary spastic paraplegias.

Impaired axonal development and degeneration underlie debilitating neurodegenerative diseases including hereditary spastic paraplegia, a large group of inherited diseases. Hereditary spastic paraplegia is caused by retrograde degeneration of the long corticospinal tract axons, leading to progressive spasticity and weakness of leg and hip muscles. There are over 70 subtypes with various underlying pathophysiological processes, such as defective vesicular trafficking, lipid metabolism, organelle shaping, axonal transport, and mitochondrial dysfunction.

Differential toxicity of processed and non-processed states of CoCrMo degradation products generated from a hip simulator on neural cells.

Physico-chemical characteristics of the CoCrMo degradation products have played an important role in cytotoxicity and clinical complications on the orthopedic patients who have metal implants. Previous studies have limited reflection on the physicochemical characteristics of the degradation products generated in vivo, which are very different from individual metal particles and/or ions obtained from different commercial sources. In this study, we aimed to understand the differences in toxicity induced by the degradation products in as-synthesized form as well as those obtained after post-processing.

Impaired mitochondrial dynamics underlie axonal defects in hereditary spastic paraplegias.

Mechanisms by which long corticospinal axons degenerate in hereditary spastic paraplegia (HSP) are largely unknown. Here, we have generated induced pluripotent stem cells (iPSCs) from patients with two autosomal recessive forms of HSP, SPG15 and SPG48, which are caused by mutations in the ZFYVE26 and AP5Z1 genes encoding proteins in the same complex, the spastizin and AP5Z1 proteins, respectively. In patient iPSC-derived telencephalic glutamatergic and midbrain dopaminergic neurons, neurite number, length and branching are significantly reduced, recapitulating disease-specific phenotypes.

Modeling Physiological Events in 2D vs. 3D Cell Culture.

Cell culture has become an indispensable tool to help uncover fundamental biophysical and biomolecular mechanisms by which cells assemble into tissues and organs, how these tissues function, and how that function becomes disrupted in disease. Cell culture is now widely used in biomedical research, tissue engineering, regenerative medicine, and industrial practices. Although flat, two-dimensional (2D) cell culture has predominated, recent research has shifted toward culture using three-dimensional (3D) structures, and more realistic biochemical and biomechanical microenvironments.

Effects of different doses of 2,3-dimercaptosuccinic acid-modified Fe O nanoparticles on intercalated discs in engineered cardiac tissues.

Although iron oxide nanoparticles (IRONs) were applied in clinical magnetic resonance imaging in vivo and magnetic tissue engineering in vitro widely, the underlying effects of IRONs on the development of cardiomyocytes especially the intercellular junctions, intercalated discs (IDs), remain an unknown issue. Given the critical role of three-dimensional (3D) engineered cardiac tissues (ECTs) in evaluation of nanoparticles toxicology, it remained necessary to understand the effects of IRONs on IDs assembly of cardiomyocytes in 3D environment. In this study, we first reconstituted collagen/Matrigel based ECTs in vitro and prepared IRONs with 2,3-dimercaptosuccinic acid (DMSA-IRONs).

Carbon nanotube-composite hydrogels promote intercalated disc assembly in engineered cardiac tissues through β1-integrin mediated FAK and RhoA pathway.

Unlabelled: Carbon nanotube (CNT)-based hydrogels have been shown to support cardiomyocyte growth and function. However, their role in cellular integrity among cardiomyocytes has not been studied in detail and the mechanisms underlying this process remain unclear. Here, single walled CNTs incorporated into gelatin with methacrylate anhydride (CNT/GelMA) hydrogels were utilized to construct cardiac tissues, which enhanced cardiomyocyte adhesion and maturation.

Carbon nanotube-based substrates promote cardiogenesis in brown adipose-derived stem cells via β1-integrin-dependent TGF-β1 signaling pathway.

Stem cell-based therapy remains one of the promising approaches for cardiac repair and regeneration. However, its applications are restricted by the limited efficacy of cardiac differentiation. To address this issue, we examined whether carbon nanotubes (CNTs) would provide an instructive extracellular microenvironment to facilitate cardiogenesis in brown adipose-derived stem cells (BASCs) and to elucidate the underlying signaling pathways.

Carbon nanotubes enhance intercalated disc assembly in cardiac myocytes via the β1-integrin-mediated signaling pathway.

Carbon nanotubes (CNTs) offer a new paradigm for constructing functional cardiac patches and repairing myocardial infarction (MI). However, little is known about how CNTs enhance the mechanical integrity and electrophysiological function of cardiac myocytes. To address this issue, we investigated the regularity and precise mechanism of the influence of CNTs on the assembly of intercalated disc (IDs).

Distribution and characteristics of telocytes as nurse cells in the architectural organization of engineered heart tissues.

Interstitial Cajal-like cells are a distinct type of interstitial cell with a wide distribution in mammalian organs and tissues, and have been given the name "telocytes". Recent studies have demonstrated the potential roles of telocytes in heart development, renewal, and repair. However, further research on the functions of telocytes is limited by the complicated in vivo environment.

Engineering the heart: evaluation of conductive nanomaterials for improving implant integration and cardiac function.

Recently, carbon nanotubes together with other types of conductive materials have been used to enhance the viability and function of cardiomyocytes in vitro. Here we demonstrated a paradigm to construct ECTs for cardiac repair using conductive nanomaterials. Single walled carbon nanotubes (SWNTs) were incorporated into gelatin hydrogel scaffolds to construct three-dimensional ECTs.

The spatiotemporal development of intercalated disk in three-dimensional engineered heart tissues based on collagen/matrigel matrix.

Intercalated disk (ID), which electromechanically couples cardiomyocytes into a functional syncitium, is closely related to normal morphology and function of engineered heart tissues (EHTs), but the development mode of ID in the three-dimensional (3D) EHTs is still unclear. In this study, we focused on the spatiotemporal development of the ID in the EHTs constructed by mixing neonatal rat cardiomyocytes with collagen/Matrigel, and investigated the effect of 3D microenvironment provided by collagen/Matrigel matrix on the formation of ID. By histological and immmunofluorescent staining, the spatiotemporal distribution of ID-related junctions was detected.

[Preparation and bio-evaluation of tissue engineered scaffold based on decellularized whole heart extracellular matrix].

Objective: To investigate a method for preparing decellularized rat heart scaffold, and to detect and evaluate the decellularized scaffold.

Methods: The decellularized rat heart scaffold was prepared by retrograde perfusion with a combination of enzymatic and Triton X-100 detergent methods to remove the populations of resident cells, and then the decellularized scaffold was observed by gross, toluidine blue staining, HE staining, scanning electron microcope (SEM), Alcian blue staining, and immunohistochemisty staining to evaluate the structure and essential component of extracellular maxtix (ECM) in the scaffold.

Results: Tissue engineered scaffold based on decellularized whole heart ECM was successfully prepared, which maintained not only the gross morphology of the heart, but also the intact vascular structure and ultrastructural conformation that certified by toluidine blue staining, HE staining, and SEM analyses.

Immunohistochemical characterization and functional identification of mammary gland telocytes in the self-assembly of reconstituted breast cancer tissue in vitro.

Telocyte (TC) as a special stromal cell exists in mammary gland and might play an important role in the balance of epithelium-stroma of mammary gland. Considering that different types of breast interstitial cells influence the development and progression of breast cancer, TCs may have its distinct role in this process. We here studied the roles of TCs in the self-assembly of reconstituted breast cancer tissue.