Mitochondrial targeting sequence of magnetoreceptor MagR:More than just targeting

Iron-sulfur clusters(ISC)are essential cofactors for proteins involved in various biological processes,such as electron transport,biosynthetic reactions,DNA repair,and gene expression regulation.ISC assembly protein IscA1(or MagR)is found within the mitochondria of most eukaryotes.Magnetoreceptor(MagR)is a highly conserved A-type iron and iron-sulfur cluster-binding protein,characterized by two distinct types of iron-sulfur clusters,[2Fe-2S]and[3Fe-4S],each conferring unique magnetic properties.MagR forms a rod-like polymer structure in complex with photoreceptive cryptochrome(Cry)and serves as a putative magnetoreceptor for retrieving geomagnetic information in animal navigation.Although the N-terminal sequences of MagR vary among species,their specific function remains unknown.In the present study,we found that the N-terminal sequences of pigeon MagR,previously thought to serve as a mitochondrial targeting signal(MTS),were not cleaved following mitochondrial entry but instead modulated the efficiency with which iron-sulfur clusters and irons are bound.Moreover,the N-terminal region of MagR was required for the formation of a stable MagR/Cry complex.Thus,the N-terminal sequences in pigeon MagR fulfil more important functional roles than just mitochondrial targeting.These results further extend our understanding of the function of MagR and provide new insights into the origin of magnetoreception from an evolutionary perspective.

N-Positive ion activated rapid addition and mitochondrial targeting ratiometric fluorescent probes for in vivo cell H_(2)S imaging

Heterocyclic compound quinoline and its derivatives exist in natural compounds and have a broad spectrum of biological activity.They play an important role in the design of new structural entities for medical applications.Similarly,indoles and their derivatives are found widely in nature.Amino acids,alkaloids and auxin are all derivatives of indoles,as are dyes,and their condensation with aldehydes makes it easy to construct reaction sites for nucleophilic addition agents.In this work,we combine these two groups organically to construct a rapid response site(within 30 s)for H_(2)S,and at the same time,a ratiometric fluorescence response is presented throughout the process of H_(2)S detection.As such,the lower detection limit can reach 55.7 nmol/L for H_(2)S.In addition,cell imaging shows that this probe can be used for the mitochondrial targeted detection of endogenous and exogenous H_(2)S.Finally,this probe application was verified by imaging H_(2)S in nude mice.

An understanding of mitochondria and its role in targeting nanocarriers for diagnosis and treatment of cancer

Nanotechnology has changed the entire paradigm of drug targeting and has shown tremendous potential in the area of cancer therapy due to its specificity. In cancer, several targets have been explored which could be utilized for the better treatment of disease. Mitochondria, the so-called powerhouse of cell, portrays significant role in the survival and death of cells, and has emerged as potential target for cancer therapy. Direct targeting and nanotechnology based approaches can be tailor-made to target mitochondria and thus improve the survival rate of patients suffering from cancer. With this backdrop, in present review, we have reemphasized the role of mitochondria in cancer progression and inhibition, highlighting the different targets that can be explored for targeting of disease. Moreover, we have also summarized different nanoparticulate systems that have been used for treatment of cancer via mitochondrial targeting.

Pre-B-cell colony-enhancing factor as a target for protecting against apoptotic neuronal death and mitochondrial damage in ischemia

Focal ischemic stroke（FIS）results from the lack of blood flow in a particular region of the brain and accounts for about 80%of all human strokes.Although tremendous efforts have been made in translational research,the treatment strategies are still limited.Tissue plasminogen activator is the only FDA-approved drug currently available for acute stroke treatment,

SLP-2: a potential new target for improving mitochondrial function in Parkinson's disease

Parkinson＇s disease （PD） is a progressive neurodegenerative disease, which is generally considered a multifactorial disorder that arises owing to a combination of genes and environmental factors. While most cases are idiopathic, in about 10% of the patients a genetic cause can be detected, ascribable to mutations in more than a dozen genes. PD is characterized clinically by tremor, rigidity, reduced mo- tor activity （bradykinesia）, and postural instability and pathological- ly by loss of dopaminergic （DA） neurons in the substantia nigra pars compacta, loss of DA innervation in the striatum, and the presence of a-synuclein positive aggregates in the form of Lewy bodies. The symptomatic treatment of PD with levodopa, which aims at replac- ing dopamine, remains the gold standard, and no neuroprotective or disease-modifying therapy is available. During treatment, the disease continues to progress, and long-term use of levodopa has import- ant limitations including motor complications termed dyskinesias. Therefore, a pharmacological therapy able to prevent or halt the neu- rodegenerative process is urgently required.

Novel mitochondrial therapies for the treatment of age-related macular degeneration

The purpose of this article is to review current literature and data regarding treatment options for age-related macular degeneration(AMD)related to mitochondrial therapy.This article considers the presence of flavoprotein fluorescence as a potential biomarker to test the effectiveness of the treatments.We focus primarily on two major mitochondrial targets,nuclear factor erythroid 2-related factor(NFE2L2)and PGC-1α,that function in controlling the production and effects of reactive oxidative species(ROS)directly in the mitochondria.PU-91 is an FDA approved drug that directly targets and upregulates PGC-1αin AMD cybrid cell lines.Although neither NFE2L2 nor PGC1-αhave yet been tested in clinical trials,their effects have been studied in rodent models and offer promising results.MTP-131,or elamipretide®,and metformin are two drugs in phase II clinical trials that focus on the treatment of advanced,non-exudative AMD.MTP-131 functions by associating with cardiolipin(CL)whereas metformin targets adenosine-monophosphate protein kinase(AMPK)in the mitochondria.The current results of their clinical trials are elucidated in this article.The molecular targets and drugs reviewed in this article show promising results in the treatment of AMD.These targets can be further pursued to improve and refine treatment practices of this diagnosis.

Electrostatic interaction-mediated 1:1 complexes for high-contrast mitochondrial-targeted phosphorescence bioimaging

Organelle-targeted imaging can provide information on cellular functions and intracellular interactions,being significant for disease diagnosis.The use of room-temperature phosphorescence(RTP)in organelle-targeted imaging can fully utilize its unique characteristics of long wavelength and deep penetration.However,this technology has long been plagued by insufficient probe targeting and limited luminous intensity.In this work,we prepared a series of complexes composed of multicationic persulfurated arenes and biomacromolecules via electrostatic interactions in 1:1 stoichiometry for high-contrast mitochondrial-targeted RTP imaging.Such an electrostatic interaction design effectively prevented the self-aggregation of the probes,which is not conducive to mitochondrial targeting.Simultaneously,it suppressed the non-radiative decay to the maximum extent,enabling the probes to exhibit strong RTP signals both in aqueous solution and at the cellular level.Furthermore,the biomacromolecules can serve as carriers for an electrostatic interaction transfer of the persulfurated arenes to mitochondria.This leads to high mitochondrial targeting Pearson's correlation coefficients of the probes and high-contrast RTP imaging effects,as well as the independence of the co-incubated probe concentration.These results provide new insights for the development of targeted imaging technologies.

Cytotoxicity of mitochondrial-targeting silica-coated manganese oxide nanoparticles

The mitochondrion is a promising target for diagnosis and therapy. Mitochondrial-targeting silica-coated manganese oxide nanoparticles(Mn O@Si O2-PPh3+ NPs) were successfully synthesized to explore the mitochondrial cytotoxicity of nanoparticles. The mitochondrial targeting property was confirmed by a laser scanning confocal microscopy experiment. Even after incubation for only 4 h, the cytotoxicity of Mn O@Si O2-PPh3+ NPs against cancer cells was obvious; the ATP content was significantly decreased to 40%; and the mitochondrial membrane potential was depleted. All of these results indicated the collapse of mitochondrial function and the start of a cell apoptosis pathway. Our findings suggest that mitochondrial-mediated apoptosis could be strengthened by targeting to the subcellular compartment.

Targeting mitochondrial biogenesis for preventing and treating insulin resistance in diabetes and obesity:Hope from natural mitochondrial nutrients

Insulin resistance is an important feature of type 2 diabetes and obesity. The underlying mechanisms of insulin resistance are still unclear. Mitochondrial dysfunction,

Mitochondrial-targeted and ROS-responsive nanocarrier via nose-to-brain pathway for ischemic stroke treatment

Oxidative stress injury and mitochondrial dysfunction are major obstacles to neurological functional recovery after ischemic stroke.The development of new approaches to simultaneously diminish oxidative stress and resist mitochondrial dysfunction is urgently needed.Inspired by the overproduced reactive oxygen species(ROS)at ischemic neuron mitochondria,multifunctional nanoparticles with ROS-responsiveness and mitochondrial-targeted(SPNPs)were engineered,achieving specific targeting delivery and controllable drug release at ischemic penumbra.Due to the nose-to-brain pathway.SPNPs which were encapsulated in a thermo-sensitive gel by intranasal administration were directly delivered to the ischemic penumbra bypassing the blood-brain barrier(BBB)and enhancing delivery efficiency.The potential of SPNPs for ischemic stroke treatment was systematically evaluated in vitro and in rat models of middle cerebral artery occlusion(MCAO).Results demonstrated the mitochondrialtargeted and protective effects of SPNPs on H2O2-induced oxidative damage in SH-SY5Y cells.In vivo distribution analyzed by fuorescence imaging proved the rapid and enhanced active targeting of SPNPs to the ischemic area in MCAO rats.SPNPs by intranasal administration exhibited superior therapeutic efficacy by alleviating oxidative stress,diminishing infammation,repairing mitochondrial function,and decreasing apoptosis.This strategy provided a multifunctional delivery system for the effective treatment of ischemic injury,which also implies a potential application prospect for other central nervous diseases.

Taming Reactive Oxygen Species:Mitochondria-Targeting Aggregation-Induced Emission Luminogen for Neuron Protection via Photosensitization-Triggered Autophagy

Oxidative damage to cells leads to accumulated harmful wastes,which in turn aggravate the imbalance of reactive oxygen species(ROS)and related diseases.Therefore,provoking the cellular defense system against severe oxidation and maintaining ROS homeostasis are desired.Herein,we designed and synthesized a powerful mitochondria-targeting aggregation-induced emission photosensitizer(named DTCSPY)by maximal restriction of heat dissipation.It is demonstrated that taming ROS generation within mitochondria through photosensitization-triggered autophagy via DTCSPY achieved a better neuroprotective effect against oxidative damages than Nacety-L-cysteine and vitamin C.This work not only provides a new way to design high-performance photosensitizers by regulating the photophysical property,but also verifies the concept that taming ROS can be used for cell protection against destructive oxidation,thereby displaying broad prospects for alleviating oxidation-related diseases and promoting cell-based therapy.

The clinical and genetic characteristics in children with mitochondrial disease in China

Mitochondrial disease was a clinically and genetically heterogeneous group of diseases, thus the diagnosis was very difficult to clinicians. Our objective was to analyze clinical and genetic characteristics of children with mitochondrial disease in China. We tested 141 candidate patients who have been suspected of mitochondrial disorders by using targeted next-generation sequencing(NGS), and summarized the clinical and genetic data of gene confirmed cases from Neurology Department, Beijing Children's Hospital, Capital Medical University from October 2012 to January 2015. In our study, 40 cases of gene confirmed mitochondrial disease including eight kinds of mitochondrial disease, among which Leigh syndrome was identified to be the most common type, followed by mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes(MELAS). The age-of-onset varies among mitochondrial disease, but early onset was common. All of 40 cases were gene confirmed, among which 25 cases(62.5%)with mitochondrial DNA(mtDNA) mutation, and 15 cases(37.5%) with nuclear DNA(nDNA) mutation. M.3243A>G(n=7)accounts for a large proportion of mtDNA mutation. The nDNA mutations include SURF1(n=7),PDHA1(n=2),and NDUFV1,NDUFAF6, SUCLA2, SUCLG1, RRM2 B, and C12orf65, respectively.

A novel two-dimensional nanoheterojunction via facilitating electron–hole pairs separation for synergistic tumor phototherapy and immunotherapy

Nanomaterial-mediated phototherapy in tumor treatment has been developed rapidly in the past few years due to its noninvasive character.However,the low energy conversion efficiency and high recombination rate of the photo-triggered electron–hole pairs of single nano-agent limit the phototherapy efficiency.Herein,we constructed a novel two-dimensional nanoheterojunction MoS_(2)-Ti_(3)C_(2)(MT),which allowed a high photothermal conversion efficiency(59.1%)as well as an effective separation of photo-triggered electron–hole pairs for reactive oxygen species(ROS)generation under single 808 nm laser irradiation.Upon the modification of the mitochondrial targeted molecule(3-proxycarboxylic)triphenyl phosphine bromide(TPP)and 4T1 cell membrane,m@MoS_(2)-Ti_(3)C_(2)/TPP(m@MTT)could effectively target to the tumor cell and further locate to the mitochondria to amplify tumor-specific oxidative stress,which not merely effectively inhibits the local tumor growth but also induces tumor immunogenic cell death(ICD)for activating antitumor immune response.Additionally,cytosine guanine dinucleotide(CPG),as a Toll-like receptor 9(TLR9)agonist,was further introduced to the system to boost adaptive immune responses,resulting in improved level of cytotoxic T cells as well as a decrease in the number of regulatory T cells.In vivo antitumor mechanism studies demonstrated that not only the primary and distant tumors in 4T1 bearing-tumor mice model were significantly inhibited,but also the lung metastasis of tumor was effectively suppressed.Therefore,this work revealed the ROS generation mechanism of MT nanoheterojunction and provided a novel strategy to fabricate a biomedically applicable MT nanoheterojunction for tumor treatment.

β-Cyclodextrin derived full-spectrum fluorescent carbon dots: The formation process investigation and biological applications

Carbon dots(CDs), a new building unit, have been revolutionizing the fields of biomedicine, bioimaging, and optoelectronics with their excellent physical, chemical, and biological properties. However, the difficulty of preparing excitation-dependent full-spectrum fluorescent CDs has seriously hindered their further research in fluorescence emission mechanisms and biomedicine. Here, we report full-spectrum fluorescent CDs that exhibit controlled emission changes from purple(380 nm) to red(613 nm) at room temperature by changing the excitation wavelength, and the excitation dependence was closely related to the regulation of sp2 and sp3 hybrid carbon structures by β-cyclodextrin-related groups. In addition,by regulating the content of β-cyclodextrin, the optimal quantum yields of full-spectrum fluorescent CDs were 8.97%, 8.35%, 7.90%, 9.69% and 17.4% at the excitation wavelengths of 340, 350, 390, 410 and 540 nm,respectively. Due to their excellent biocompatibility and color tunability, full-spectrum fluorescent CDs emitted bright and steady purple, blue, green, yellow, and red fluorescence in MCF-7 cells. Moreover, we optimized the imaging conditions of CDs and mitochondrial-specific dyes;and realized the mitochondrialtargeted co-localization imaging of purple, blue and green fluorescence. After that, we also explored the effect of full-spectrum fluorescent CDs in vivo fluorescence imaging through the intratumorally, subcutaneously, and caudal vein, and found that full-spectrum fluorescent CDs had good fluorescence imaging ability in vivo.

Dual-targeted nanoformulation with Janus structure for synergistic enhancement of sonodynamic therapy and chemotherapy

The accurate delivery of nanoparticles and organic small molecule drugs remains a serious challenge in nanoparticle-based tumor therapy.Dual-targeted therapy combining tumor cell targeting and organelle targeting is an effective solution.Here,an anticancer nanoformulation accurate delivery system was prepared using hyaluronic acid (HA) targeting CD44 receptors on the surface of tumor cells and IR780iodine (IR780) targeting mitochondrial for delivery.The system is based on an ultra-small Janus structured inorganic sensitizer TiO_(2-x)@NaGdF_(4) nanoparticles (TN NPs) prepared by one-step pyrolysis,further loaded with organic small molecule acoustic sensitizer IR780 and mitochondrial hexokinase Ⅱ inhibitor lonidamine (LND),followed by encapsulation of HA.Ultra-small size nanoparticles exhibit strong tissue penetration,tumor inhibition and in vivo metabolism.Under ultrasound radiation,TN NPs and IR780could produce a synergistic effect,effectively increased the efficiency of reactive oxygen species (ROS)production.Meanwhile,the released IR780 could smoothly target the mitochondria,and the ROS produced by IR780 can destroy the mitochondrial structure and disrupt the mitochondrial respiration.LND could inhibit the energy metabolism of tumor cells by reducing the activity of hexokinase Ⅱ (HK Ⅱ),which further accelerates the process of apoptosis.Furthermore,since the Janus structure allows the integration of multifunctional components into a single system,TN NPs can not only serve as an acoustic sensitizer to generate ROS,but the Gd element contained can also act as the nuclear magnetic resonance (MR)imaging contrast agent,suggesting that the nanoformulation can enable imaging-guided diagnosis and therapy.In conclusion,a new scheme to enhance sonodynamic therapy (SDT) and chemotherapy synergistically is proposed here based on ultra-small dual-targeted nanoformulation with Janus structure in the ultrasound radiation environment.

自噬小体绑定化合物(ATTEC)靶向降解线粒体及其潜在治疗效果

功能异常的线粒体的累积会诱发多种神经退化相关疾病,如帕金森氏病(PD)和唐氏综合征(DS).借助小分子化合物促进线粒体的降解被认为可以缓解这类疾病的进程.然而,目前尚缺乏这样一类高效、安全的靶向降解线粒体的小分子化合物.本研究借助一种名为自噬小体绑定化合物(ATTEC)的新型靶向降解技术,创造性地合成一种能同时结合自噬关键分子LC3B以及线粒体外膜蛋白TSPO的小分子化合物—mT1,并发现该化合物能够有效地降解细胞中的线粒体.借助分子生物学及细胞生物学手段,作者证明mT1能够促进LC3B和TSPO结合,从而将线粒体靶向自噬小体,并进一步与溶酶体融合而降解.此外,在PD的细胞模型和DS的类器官模型中证明mT1能够通过促进线粒体的清除而改善相应的病理学表型.该研究将ATTEC技术的应用范畴拓展到亚细胞器的层面,并为以PD和DS为代表的一类线粒体异常引起的疾病提供了一种潜在的新治疗策略.

Multi-responsive nanotheranostics with enhanced tumor penetration and oxygen self-producing capacities for multimodal synergistic cancer therapy

Incorporation of multiple functions into one nanoplatform can improve cancer diagnostic efficacy and enhance anti-cancer outcomes. Here, we constructed doxorubicin(DOX)-loaded silk fibroinbased nanoparticles(NPs) with surface functionalization by photosensitizer(N770). The obtained nanotheranostics(N770-DOX@NPs) had desirable particle size(157 nm) and negative surface charge(-25 m V). These NPs presented excellent oxygen-generating capacity and responded to a quadruple of stimuli(acidic solution, reactive oxygen species, glutathione, and hyperthermia). Surface functionalization of DOX@NPs with N770 could endow them with active internalization by cancerous cell lines, but not by normal cells. Furthermore, the intracellular NPs were found to be preferentially retained in mitochondria, which were also efficient for near-infrared(NIR) fluorescence imaging, photothermal imaging,and photoacoustic imaging. Meanwhile, DOX could spontaneously accumulate in the nucleus. Importantly, a mouse test group treated with N770-DOX@NPs plus NIR irradiation achieved the best tumorretardation effect among all treatment groups based on tumor-bearing mouse models and a patientderived xenograft model, demonstrating the unprecedented therapeutic effects of trimodal imagingguided mitochondrial phototherapy(photothermal therapy and photodynamic therapy) and chemotherapy.Therefore, the present study brings new insight into the exploitation of an easy-to-use, versatile, and robust nanoplatform for programmable targeting, imaging, and applying synergistic therapy to tumors.

Stimuli-responsive nano vehicle enhances cancer immunotherapy by coordinating mitochondria-targeted immunogenic cell death and PD-L1 blockade

Induction of immunogenic cell death promotes antitumor immunity against cancer. However, majority of clinically-approved drugs are unable to elicit sufficient ICD. Here, our study revealed that mitochondria-targeted delivery of doxorubicin(DOX) massively amplified ICD via substantial generation of reactive oxygen species(ROS) after mitochondrial damage. The underlying mechanism behind increased ICD was further demonstrated to be ascribed to two pathways:(1) ROS elevated endoplasmic reticulum(ER) stress, leading to surface exposure of calreticulin;(2) ROS promoted release of various mitochondriaassociated damage molecules including mitochondrial transcription factor A. Nevertheless, adaptive upregulation of PD-L1 was found after such ICD-inducing treatment. To overcome such immunosuppressive feedback,we developed a tumor stimuli-responsive nano vehicle to simultaneously exert mitochondrial targeted ICD induction and PD-L1 blockade. The nano vehicle was self-assembled from ICD-inducing copolymer and PD-L1 blocking copolymer, and possessed long-circulating property which contributed to better tumor accumulation and mitochondrial targeting. As a result, the nano vehicle remarkably activated antitumor immune responses and exhibited robust antitumor efficacy in both immunogenic and non-immunogenic tumor mouse models.

Photoacoustic-immune therapy with a multi-purpose black phosphorus-based nanoparticle

Effective therapeutic strategies to precisely eradicate primary tumors with minimal side effects on normal tissue,inhibit metastases,and prevent tumor relapses,are the ultimate goals in the battle against cancer.We report a novel therapeutic strategy that combines adjuvant black phosphorus nanoparticle-based photoacoustic(PA)therapy with checkpoint-blockade immunotherapy.With the mitochondria targeting nanoparticle,PA therapy can achieve localized mechanical damage of mitochondria via PA cavitation and thus achieve precise eradication of the primary tumor.More importantly,PA therapy can generate tumor-associated antigens via the presence of the R848-containing nanoparticles as an adjuvant to promote strong antitumor immune responses.When combined with the checkpoint-blockade using anti-cytotoxic T-lymphocyte antigen-4,the generated immunological responses will further promote the infiltrating CD8 and CD4 T-cells to increase the CD8/Foxp3 T-cell ratio to inhibit the growth of distant tumors beyond the direct impact range of the PA therapy.Furthermore,the number of memory T cells detected in the spleen is increased,and these cells inhibit tumor recurrence.This proposed strategy offers precise eradication of the primary tumor and can induce long-term tumor-specific immunity.