TAT-PEP Alleviated Cognitive Impairment by Alleviating Neuronal Mitochondria Damage and Apoptosis After Cerebral Ischemic Reperfusion Injury.

Paired immunoglobulin-like receptor B (PirB) was identified as a myelin-associated inhibitory protein (MAIP) receptor that plays a critical role in axonal regeneration, synaptic plasticity and neuronal survival after stroke. In our previous study, a transactivator of transcription-PirB extracellular peptide (TAT-PEP) was generated that can block the interactions between MAIs and PirB. We found that TAT-PEP treatment improved axonal regeneration, CST projection and long-term neurobehavioural recovery after stroke through its effects on PirB-mediated downstream signalling. However, the effect of TAT-PEP on the recovery of cognitive function and the survival of neurons also needs to be investigated. In this study, we investigated whether pirb RNAi could alleviate neuronal injury by inhibiting the expression of PirB following exposure to oxygen-glucose deprivation (OGD) in vitro. In addition, TAT-PEP treatment attenuated the volume of the brain infarct and promoted the recovery of neurobehavioural function and cognitive function. This study also found that TAT-PEP exerts neuroprotection by reducing neuronal degeneration and apoptosis after ischemia-reperfusion injury. In addition, TAT-PEP improved neuron survival and reduced lactate dehydrogenase (LDH) release in vitro. Results also showed that TAT-PEP reduced malondialdehyde (MDA) levels, increased superoxide dismutase (SOD) activity and reduced reactive oxygen species (ROS) accumulation in OGD-injured neurons. The possible mechanism was that TAT-PEP could contribute to the damage of neuronal mitochondria and affect the expression of cleaved caspase 3, Bax and Bcl-2. Our results suggest that PirB overexpression in neurons after ischaemic-reperfusion injury induces neuronal mitochondrial damage, oxidative stress and apoptosis. This study also suggests that TAT-PEP may be a potent neuroprotectant with therapeutic potential for stroke by reducing neuronal oxidative stress, mitochondrial damage, degeneration and apoptosis in ischemic stroke.

Pelargonidin ameliorates reserpine-induced neuronal mitochondrial dysfunction and apoptotic cascade: a comparative in vivo study.

BACKGROUND: Targeting the neuronal mitochondria as a possible intervention to guard against neurodegenerative disorder progression has been investigated in the current work via the administration of pelargonidin (PEL) to rats intoxicated by the mitochondrial toxin reserpine. The main criteria for choosing PEL were its reported antioxidant, anti-apoptotic and anti-inflammatory activities. METHODS: Male albino Wistar rats were randomized into five experimental groups; normal control, reserpinized to induce mitochondrial failure, standard PARP-1-inhibitor 1,5-isoquinolinediol (DIQ)-treated reserpinized, PEL-treated reserpinized, and GSK-3ß inhibitor (AR-A 014418) -treated reserpinized. RESULTS: PEL administration reversed the reserpine-induced abnormal behaviors marked by decreased catalepsy time. In addition, PEL restored brain glutathione with a reduction in nitric oxide content as compared to the reserpine-challenged group. Meanwhile, it improved neuronal mitochondrial function by the elevation of complex I activity associated with a low ADP/ATP ratio. Likely through its anti-inflammatory effect, PEL reduced the elevation of serum interleukin-1ß level and inhibited serum lactate dehydrogenase activity. These findings are aligned with the reduced expression of cleaved PARP and cleaved caspase-3 proteins, indicating PEL's suppressive effect on the intrinsic apoptotic pathway. Those biochemical findings were confirmed through comparable histopathological tissue examination among the experimental groups. CONCLUSIONS: In conclusion, PEL is a promising candidate for future use in the management of mitochondria-associated neuronal complications via controlling the ongoing inflammatory and degeneration cascades.

Targeted delivery of PARP inhibitors to neuronal mitochondria via biomimetic engineered nanosystems in a mouse model of traumatic brain injury.

Traumatic brain injury (TBI) is known to activate poly (ADP-ribose) polymerase (PARP-1), which leads to pronounced negative effects on mitochondrial DNA (mt-DNA) repair and function. Notably, PARP inhibitors are reported to be beneficial in experimental models of TBI. A targeting strategy for the delivery of neuronal mitochondria-specific PARP inhibitors could result in a greater neuroprotective effect and be a safer approach for TBI treatment. In the present study, we developed the PARP inhibitor olaparib (Ola) as a model drug and devised red blood cell (RBC)-coated nanostructured lipid carriers (RBCNLCs) co-modified with C3 and SS31 peptide (C3/SS31-RBCNLCs) for brain neuronal mitochondria-targeting. Our results indicated that biomimetic nanosystems have the physical and chemical properties of the NLCs, as well as the biological properties of RBC. A high concentration of Ola delivered into brain mitochondria by C3/SS31-RBCNLCs-Ola effectively improved mitochondrial function and prevented neuronal cell death caused by excessive activation of injury-induced mitochondrial PARP (mt-PARP) in vitro and in vivo. Taken together, the results of this study support the preclinical feasibility of developing highly effective nano-drugs as part of precision medicine for TBI. STATEMENT OF SIGNIFICANCE: TBI-induced neuronal mitochondria DNA damage activates Poly(ADP-ribose) Polymerase (PARP1) which leads to a pronounced negative effect on mitochondrial DNA repair and mitochondrial function. In recent years, PARP inhibitors showed strong benefits in experimental models of TBI, more importantly PARP inhibitors specially target neuronal mitochondria may play a greater neuroprotective role and may be a safer approach for TBI treatment. Herein, we designed red blood cell (RBC) membrane-coated nanostructure lipid carriers dual-modified with C3 and SS31 (C3/SS31-RBCNLCs) to accomplish these objectives. After encapsulating Olaparib (Ola) as the model PARP inhibitor, the data demonstrated that C3/SS31-RBCNLCs, with brain neuronal mitochondria targeting, can reduce neuronal cell death and improve mitochondrial dysfunction triggered by mitochondrial PARP activation in vitro and in vivo.

Near-Infrared Radiation-Assisted Drug Delivery Nanoplatform to Realize Blood-Brain Barrier Crossing and Protection for Parkinsonian Therapy.

Mitochondrial dysfunction, which is directly involved in Parkinson's disease (PD), is characterized by the production of reactive oxygen species (ROS) and aberrant energy metabolism. Thus, regulating mitochondrial function might be an effective strategy to treat PD. However, the blood-brain barrier (BBB) presents a significant challenge for the intracerebral delivery of drugs. Here, we synthesized a zeolitic imidazolate framework 8-coated Prussian blue nanocomposite (ZIF-8@PB), which was encapsulated with quercetin (QCT), a natural antioxidant, to treat PD. ZIF-8@PB-QCT exhibited superior near-infrared radiation (NIR) response and penetrated through the BBB to the site of mitochondrial damage guided by the photothermal effect. In the mice model of PD, the QCT released from ZIF-8@PB-QCT significantly increased the adenosine triphosphate levels, reduced the oxidative stress levels, and reversed dopaminergic neuronal damage as well as PD-related behavioral deficits without any damage to the normal tissues. Furthermore, we explored the underlying neuroprotective mechanism of ZIF-8@PB-QCT that was mediated by activating the PI3K/Akt signaling pathway. Thus, combined with noninvasive NIR radiation, the biocompatible ZIF-8@PB-QCT nanocomposite could be used to treat neurodegenerative diseases.

Macrophage membrane-coated nanocarriers Co-Modified by RVG29 and TPP improve brain neuronal mitochondria-targeting and therapeutic efficacy in Alzheimer's disease mice.

Neuronal mitochondrial dysfunction caused by excessive reactive oxygen species (ROS) is an early event of sporadic Alzheimer's disease (AD), and considered to be a key pathologic factor in the progression of AD. The targeted delivery of the antioxidants to mitochondria of injured neurons in brain is a promising therapeutic strategy for AD. A safe and effective drug delivery system (DDS) which is able to cross the blood-brain barrier (BBB) and target neuronal mitochondria is necessary. Recently, bioactive materials-based DDS has been widely investigated for the treatment of AD. Herein, we developed macrophage (MA) membrane-coated solid lipid nanoparticles (SLNs) by attaching rabies virus glycoprotein (RVG29) and triphenylphosphine cation (TPP) molecules to the surface of MA membrane (RVG/TPP-MASLNs) for functional antioxidant delivery to neuronal mitochondria. According to the results, MA membranes camouflaged the SLNs from being eliminated by RES-rich organs by inheriting the immunological characteristics of macrophages. The unique properties of the DDS after decoration with RVG29 on the surface was demonstrated by the ability to cross the BBB and the selective targeting to neurons. After entering the neurons in CNS, TPP further lead the DDS to mitochondria driven by electric charge. The Genistein (GS)- encapsulated DDS (RVG/TPP-MASLNs-GS) exhibited the most favorable effects on reliveing AD symptoms in vitro and in vivo by the synergies gained from the combination of MA membranes, RVG29 and TPP. These results demonstrated a promising therapeutic candidate for delaying the progression of AD via neuronal mitochondria-targeted delivery by the designed biomimetic nanosystems.

Neuronal mitochondria-targeted therapy for Alzheimer's disease by systemic delivery of resveratrol using dual-modified novel biomimetic nanosystems.

Reactive oxygen species (ROS)-induced neuronal mitochondrial dysfunction is a key pathologic factor in sporadic Alzheimer's disease (AD). Neuronal mitochondria have been proposed to be a promising therapeutic target for AD, especially for the failures of phase III clinical trials on conventional amyloid-ß (Aß) targeted therapy. However, the efficient intravenous delivery of therapeutic agents to neuronal mitochondria in the brain remains a major challenge due to the complicated physiological environment. Recently, biomaterials-based nanomedicine has been widely investigated for the treatment of AD. Herein, we devised a strategy for functional antioxidant delivery to neuronal mitochondria by loading antioxidants into red blood cell (RBC) membrane-coated nanostructured lipid carriers (NLC) bearing rabies virus glycoprotein (RVG29) and triphenylphosphine cation (TPP) molecules attached to the RBC membrane surface (RVG/TPP NPs@RBCm). With the advantage of suitable physicochemical properties of NLC and unique biological functions of the RBC membrane, RVG/TPP NPs@RBCm are stabilized and enabled sustained drug release, providing improved biocompatibility and long-term circulation. Under the synergistic effects of RVG29 and TPP, RVG/TPP NPs@RBCm can not only penetrate the blood-brain barrier (BBB) but also target neuron cells and further localize in the mitochondria. After encapsulating Resveratrol (RSV) as the model antioxidant, the data demonstrated that RVG/TPP-RSV NPs@RBCm can relieve AD symptoms by mitigating Aß-related mitochondrial oxidative stress both in vitro and in vivo. The memory impairment in APP/PS1 mice is significantly improved following the systemic administration of RVG/TPP-RSV NPs@RBCm. In conclusion, intravenous neuronal mitochondria-targeted dual-modified novel biomimetic nanosystems are a promising therapeutic candidate for ROS-induced mitochondrial dysfunction in AD.

Neuronal mitochondria-targeted delivery of curcumin by biomimetic engineered nanosystems in Alzheimer's disease mice.

Biomimetic nanotechnology represents a promising approach for the delivery of therapeutic agents for the treatment of complex diseases. Recently, neuronal mitochondria have been proposed to serve as a promising therapeutic target for sporadic Alzheimer's disease (AD). However, the efficient intravenous delivery of therapeutic agents to neuronal mitochondria in the brain remains a major challenge due to the complicated physiological and pathological environment. Herein, we devised and tested a strategy for functional antioxidant delivery to neuronal mitochondria by loading antioxidants into red blood cell (RBC) membrane-camouflaged human serum albumin nanoparticles bearing T807 and triphenylphosphine (TPP) molecules attached to the RBC membrane surface (T807/TPP-RBC-NPs). With the advantage of the suitable physicochemical properties of the nanoparticles and the unique biological functions of the RBC membrane, the T807/TPP-RBC-NPs are stabilized and promote sustained drug release, providing improved biocompatibility and long-term circulation. Under the synergistic effects of T807 and TPP, T807/TPP-RBC-NPs can not only penetrate the blood-brain barrier (BBB) but also target nerve cells and further localize in the mitochondria. After encapsulating curcumin (CUR) as the model antioxidant, the research data demonstrated that CUR-loaded T807/TPP-RBC-NPs can relieve AD symptoms by mitigating mitochondrial oxidative stress and suppressing neuronal death both in vitro and in vivo. In conclusion, the intravenous neuronal mitochondria-targeted biomimetic engineered delivery nanosystems provides an effective drug delivery platform for brain diseases. STATEMENT OF SIGNIFICANCE: The efficient intravenous delivery of therapeutic agents to neuronal mitochondria in the brain remains a major challenge for drug delivery due to the complicated physiological and pathological environment. To address this need, various types of nanovessels have been fabricated using a variety of materials in the last few decades. However, problems with the synthetic materials still exist and even cause toxicology issues. New findings in nanomedicine are promoting the development of biomaterials. Herein, we designed a red blood cell (RBC) membrane-coated human serum albumin nanoparticle dual-modified with T807 and TPP (T807/TPP-RBC-NPs) to accomplish these objectives. After encapsulating curcumin as the model drug, the research data demonstrated that the intravenous neuronal mitochondria-targeted biomimetic engineered delivery nanosystems are a promising therapeutic candidate for mitochondrial dysfunction in Alzheimer's disease (AD).

Defending stressed mitochondria: uncovering the role of MUL1 in suppressing neuronal mitophagy.

Chronic mitochondrial stress is associated with major neurodegenerative diseases; and thus, the recovery of those mitochondria constitutes a critical step of energy maintenance in early stages of neurodegeneration. Our recent study provides the first lines of evidence showing that the MUL1-MFN2 pathway acts as an early checkpoint to maintain mitochondrial integrity by regulating mitochondrial morphology and interplay with the endoplasmic reticulum (ER). This mechanism ensures that degradation through mitophagy is restrained in neurons under early stress conditions. MUL1 deficiency increases MFN2 activity, triggering the first phase of mitochondrial hyperfusion and acting as an antagonist of ER-mitochondria (ER-Mito) tethering. Reduced ER-Mito interplay enhances the cytoplasmic Ca2+ load that induces the DNM1L/Drp1-dependent second phase of mitochondrial fragmentation and mitophagy. Our study provides new mechanistic insights into neuronal mitochondrial maintenance under stress conditions. Identifying this pathway is particularly relevant because chronic mitochondrial dysfunction and altered ER-Mito contacts have been reported in major neurodegenerative diseases.

Age-Related Phasic Patterns of Mitochondrial Maintenance in Adult Caenorhabditis elegans Neurons.

Aging is associated with cognitive decline and increasing risk of neurodegeneration. Perturbation of mitochondrial function, dynamics, and trafficking are implicated in the pathogenesis of several age-associated neurodegenerative diseases. Despite this fundamental importance, the critical understanding of how organismal aging affects lifetime neuronal mitochondrial maintenance remains unknown, particularly in a physiologically relevant context. To address this issue, we performed a comprehensive in vivo analysis of age-associated changes in mitochondrial morphology, density, trafficking, and stress resistance in individual Caenorhabditis elegans neurons throughout adult life. Adult neurons display three distinct stages of increase, maintenance, and decrease in mitochondrial size and density during adulthood. Mitochondrial trafficking in the distal neuronal processes declines progressively with age starting from early adulthood. In contrast, long-lived daf-2 mutants exhibit delayed age-associated changes in mitochondrial morphology, constant mitochondrial density, and maintained trafficking rates during adulthood. Reduced mitochondrial load at late adulthood correlates with decreased mitochondrial resistance to oxidative stress. Revealing aging-associated changes in neuronal mitochondria in vivo is an essential precedent that will allow future elucidation of the mechanistic causes of mitochondrial aging. Thus, our study establishes the critical foundation for the future analysis of cellular pathways and genetic and pharmacological factors regulating mitochondrial maintenance in aging- and disease-relevant conditions. SIGNIFICANCE STATEMENT: Using Caenorhabditis elegans as a model, we address long-standing questions: How does aging affect neuronal mitochondrial morphology, density, trafficking, and oxidative stress resistance? Are these age-related changes amenable to genetic manipulations that slow down the aging process? Our study illustrates that mitochondrial trafficking declines progressively from the first day of adulthood, whereas mitochondrial size, density, and resistance to oxidative stress undergo three distinct stages: increase in early adulthood, maintenance at high levels during mid-adulthood, and decline during late adulthood. Thus, our study characterizes mitochondrial aging profile at the level of a single neuron in its native environment and establishes the critical foundation for the future genetic and pharmacological dissection of factors that influence long-term mitochondrial maintenance in neurons.