Kinesin motor KIF16A regulates microtubule stability and actin-dependent spindle migration in mouse oocyte meiosis.

Kif16A, a member of the kinesin-3 family of motor proteins, has been shown to play crucial roles in inducing mitotic arrest, apoptosis, and mitotic cell death. However, its roles during oocyte meiotic maturation have not been fully defined. In this study, we report that Kif16A exhibits unique accumulation on the spindle apparatus and colocalizes with microtubule fibers during mouse oocyte meiotic maturation. Targeted depletion of Kif16A using gene-targeting siRNA disrupts the progression of the meiotic cell cycle. Furthermore, Kif16A depletion leads to aberrant spindle assembly and chromosome misalignment in oocytes. Our findings also indicate that Kif16A depletion reduces tubulin acetylation levels and compromises microtubule resistance to depolymerizing drugs, suggesting its crucial role in microtubule stability maintenance. Notably, we find that the depletion of Kif16A results in a notably elevated incidence of defective kinetochore-microtubule attachments and the absence of BubR1 localization at kinetochores, suggesting a critical role for Kif16A in the activation of the spindle assembly checkpoint (SAC) activity. Additionally, we observe that Kif16A is indispensable for proper actin filament distribution, thereby impacting spindle migration. In summary, our findings demonstrate that Kif16A plays a pivotal role in regulating microtubule and actin dynamics crucial for ensuring both spindle assembly and migration during mouse oocyte meiotic maturation.

A mitochondria-targeting heptamethine cyanine-chlorambucil formulated polymeric nanoparticle to potentiate native tumor chemotherapeutic efficacy.

Chlorambucil (Cbl) is a DNA alkylating drug in the nitrogen mustard family, but the clinical applications of nitrogen mustard antitumor drugs are frequently limited by their poor aqueous solubility, poor cellular uptake, lack of targeting, and severe side effects. Additionally, mitochondria are the energy factories for cells, and tumor cells are more susceptible to mitochondrial dysfunction than some healthy cells, thus making mitochondria an important target for tumor therapy. As a proof-of-concept, direct delivery of Cbl to tumor cells' mitochondria will probably bring about new opportunities for the nitrogen mustard family. Furthermore, IR775 chloride is a small-molecule lipophilic cationic heptamethine cyanine dye with potential advantages of mitochondria targeting, near-infrared (NIR) fluorescence imaging, and preferential internalization towards tumor cells. Here, an amphiphilic drug conjugate was facilely prepared by covalently coupling chlorambucil with IR775 chloride and further self-assembly to form a carrier-free self-delivery theranostic system, in which the two components are both functional units aimed at theranostic improvement. The theranostic IR775-Cbl potentiated typical "1 + 1 > 2" tumor inhibition through specific accumulation in mitochondria, which triggered a remarkable decrease in mitochondrial membrane potential and ATP generation. In vivo biodistribution and kinetic monitoring were achieved by real-time NIR fluorescence imaging to observe its transport inside a living body. Current facile mitochondria-targeting modification with clinically applied drugs was promising for endowing traditional drugs with targeting, imaging, and improved potency in disease theranostics.

Alpha-lipoic acid supplementation reverses the declining quality of oocytes exposed to cyclophosphamide.

Cyclophosphamide (CY) is a chemotherapeutic drug that is commonly used to treat malignancies of the ovary, breast, and hematology, as well as autoimmune disorders. As a cofactor of mitochondrial multienzyme complexes, alpha lipoic acid (ALA) is well known for its antioxidant characteristics, which operate directly on the scavenging of reactive oxygen species (ROS) and indirectly on the intracellular recycling of other antioxidants. However, the underlying mechanisms through which CY exerts its toxic effects on meiosis and oocyte quality, as well as a viable approach for protecting oocyte quality and preserving fertility, remain unknown. In present study, immunostaining and fluorescence intensity quantification were applied to assess the effects of CY and ALA supplementation on the key processes during the oocyte meiotic maturation. Our results show that supplementing oocytes with ALA, a well-known antioxidant and free radical scavenger, can reverse CY-induced oocyte meiotic maturation failure. Specifically, we found that CY exposure caused oocyte meiotic failure by disrupting meiotic organelle dynamics and arrangement, as well as a prominently impaired cytoskeleton assembly. In addition, CY caused an abnormal distribution of mitochondrion and cortical granules, two indicators of oocyte cytoplasmic maturation. More importantly, we show that ALA supplementation effectively reverses CY-induced meiotic failure and oocyte quality decline by suppressing oxidative stress-induced DNA damage and apoptosis in oocytes. Collectively, our data reveal that ALA supplementation is a feasible approach to protect oocytes from CY-exposed deterioration, providing a better understanding of the mechanisms involved in chemotherapy-induced meiotic failure.

A Native Drug-Free Macromolecular Therapeutic to Trigger Mutual Reinforcing of Endoplasmic Reticulum Stress and Mitochondrial Dysfunction for Cancer Treatment.

Drug-free macromolecular therapeutics are promising alternatives to traditional drugs. Nanomedicines with multiple organelles targeting can potentially increase the efficacy. Herein, a drug-free macromolecular therapeutic was designed to formulate endoplasmic reticulum (ER) and mitochondria dual-targeting nanoparticles (EMT-NPs), which can synergistically elicit ER stress and mitochondrial dysfunction. In vitro experiments indicated that EMT-NPs could effectively enter ER and mitochondria at an approximate ratio of 2 to 3. Subsequently, EMT-NPs could upregulate ER stress-related protein expression (IRE1α, CHOP), boosting calcium ion (Ca2+) efflux and activating the caspase-12 signaling cascade in cancer cells. In addition, EMT-NPs induced direct oxidative stress in mitochondria; some mitochondrial-related apoptotic events such as decreased mitochondrial membrane potential (MMP), upregulation of Bax, cytochrome c release, and caspase-3 activation were also observed for tumor cells upon incubation with EMT-NPs. Furthermore, the leaked Ca2+ from ER could induce mitochondrial Ca2+ overloading to further augment cancer cell apoptosis. In brief, mitochondrial and ER signaling networks collaborated well to promote cancer cell death. Extended photoacoustic and fluorescence imaging served well for the treatment of in vivo patient-derived xenografts cancer model. This drug-free macromolecular strategy with multiple subcellular targeting provides a potential paradigm for cancer theranostics in precision nanomedicine.

Alpha-lipoic acid supplementation restores the meiotic competency and fertilization capacity of porcine oocytes induced by arsenite.

Arsenite is known as a well-known endocrine disrupting chemicals, and reported to be associated with an increased incidence of negative health effects, including reproductive disorders and dysfunction of the endocrine system. However, it still lacks of the research regarding the beneficial effects of ALA on arsenite exposed oocytes, and the underlying mechanisms have not been determined. Here, we report that supplementation of alpha-lipoic acid (ALA), a strong antioxidant naturally present in all cells of the humans, is able to restore the declined meiotic competency and fertilization capacity of porcine oocytes induced by arsenite. Notably, ALA recovers the defective nuclear and cytoplasmic maturation of porcine oocytes caused by arsenite exposure, including the impaired spindle formation and actin polymerization, the defective mitochondrion integrity and cortical granules distribution. Also, ALA recovers the compromised sperm binding ability to maintain the fertilization potential of arsenite-exposed oocytes. Importantly, ALA suppresses the oxidative stress by reducing the levels of ROS and inhibits the occurrence of DNA damage along with apoptosis. Above all, we provide a new perspective for the application of ALA in effectively preventing the declined oocyte quality induced by environmental EDCs.