Mitochondrial fragmentation limits NK cell-based tumor immunosurveillance

Prospects and limitations of NK cell adoptive therapy in clinical applications

During the last three decades, there has been substantial advancement in comprehending the chemical attributes and roles of natural killer (NK) cells, resulting in a growing interest in these cells. Simultaneously, the swift advancement of adoptive transfer therapy for immune cells, particularly the impressive achievements of autologous chimeric antigen receptor-T (CAR-T) cells in treating hematological malignant tumors, has fueled interest in using immune cells as a cancer treatment modality and opened the door for NK cell adoptive immunotherapy. NK cell-mediated immunotherapy has shown potential as a readily available, safe, and effective treatment for patients with leukemia. Moreover, clinical studies have demonstrated that NK cell adoptive immunotherapy shows efficacy in various solid tumors and hematologic malignancies, indicating a promising future for this therapeutic approach. This paper will provide an overview of NK cell adoptive therapy, focusing on current clinical trial results and the challenges associated with clinical applications.

Role of mitochondria in physiological activities, diseases, and therapy

Mitochondria are generally considered essential for life in eukaryotic organisms because they produce most of the energy or adenosine triphosphate (ATP) needed by the cell. Beyond energy production, it is now widely accepted that mitochondria also play a pivotal role in maintaining cellular homeostasis and signaling. The two core processes of mitochondrial dynamics, fission and fusion, serve as crucial foundations for maintaining mitochondrial morphology, distribution, and quantity, thereby ensuring cellular homeostasis. Mitochondrial autophagy (mitophagy) ensures the selective degradation of damaged mitochondria, maintaining quality control. Mitochondrial transport and communication further enhance their role in cellular processes. In addition, mitochondria are susceptible to damage, resulting in dysfunction and disruption of intracellular homeostasis, which is closely associated with the development of numerous diseases. These include mitochondrial diseases, neurodegenerative diseases, cardiovascular diseases (CVDs) and stroke, metabolic disorders such as diabetes mellitus, cancer, infectious diseases, and the aging process. Given the central role of mitochondria in disease pathology, there is a growing need to understand their mechanisms and develop targeted therapies. This review aims to provide a comprehensive overview of mitochondrial structure and functions, with a particular focus on their roles in disease development and the current therapeutic strategies targeting mitochondria. These strategies include mitochondrial-targeted antioxidants, modulation of mitochondrial dynamics and quality control, mitochondrial genome editing and genetic therapy, and mitochondrial transplantation. We also discuss the challenges currently facing mitochondrial research and highlight potential future directions for development. By summarizing the latest advancements and addressing gaps in knowledge, this review seeks to guide future research and clinical efforts in the field of mitochondrial medicine.

The spatiotemporal heterogeneity of reactive oxygen species in the malignant transformation of viral hepatitis to hepatocellular carcinoma: a new insight

During the transformation of viral hepatitis into hepatocellular carcinoma (HCC), oxidative stress levels increase significantly, leading to tissue damage and chronic inflammation. HCC is characterized by spatiotemporal heterogeneity, which influences oxidative stress patterns, with reactive oxygen species (ROS) as the primary representative molecules. ROS serve not only as critical biomarkers of cancer but also as potential therapeutic targets for HCC, given that their increased levels can either promote or inhibit disease progression. In this review, we systematically examine the temporal heterogeneity of ROS, emphasizing its role in different stages of HCC progression caused by viral hepatitis and in influencing cell fate. We further explore ROS spatial heterogeneity at three levels: cellular, organelle, and biomolecular. Next, we comprehensively review clinical applications and potential therapies designed to selectively modulate ROS on the basis of its spatiotemporal heterogeneity. Finally, we discuss potential future applications of novel therapies that target ROS spatiotemporal heterogeneity to prevent and manage HCC onset and progression. In conclusion, this review enhances understanding of ROS in the progression of viral hepatitis to HCC and offers insights into developing new therapeutic targets and strategies centered on ROS heterogeneity.

Cancer-derived extracellular vesicles in natural killer cell immune evasion: Molecular mechanisms and therapeutic insights

Natural killer cells are innate lymphocytes equipped with the ability to rapidly identify and eliminate cancer cells. However, cancer cells release nanosized extracellular vesicles that can induce an immunosuppressive tumor microenvironment, subsequently hindering natural killer cell immunosurveillance. Studies have reported that extracellular vesicles derived from different cancers, such as acute myeloid leukemia, melanoma, mesothelioma, head and neck squamous carcinoma, lung carcinoma, breast cancer, hepatocellular carcinoma, and pancreatic ductal adenocarcinoma, can induce natural killer cell dysfunction by suppressing cytolytic proteins and downregulating expression of receptors involved in the recognition of oncogenic cells. Additionally, cancer-derived extracellular vesicles can interfere with natural killer cell survival, proliferation, cell migration, and metabolic functions. Therefore, extracellular vesicle-induced natural killer cell suppression has emerged as a key target for research and new therapeutic approaches to recover and enhance the tumoricidal potential of these immune cells. Here, we summarize the current knowledge regarding cancer-derived extracellular vesicles and natural killer cell interactions, their role in immunosuppression, implications for developing efficient cellular immunotherapies and outstanding questions in this field.

From powerhouse to modulator: regulating immune system responses through intracellular mitochondrial transfer

Mitochondria are traditionally known as the cells' powerhouses; however, their roles go far beyond energy suppliers. They are involved in intracellular signaling and thus play a crucial role in shaping cells' destiny and functionality, including immune cells. Mitochondria can be actively exchanged between immune and non-immune cells via mechanisms such as nanotubes and extracellular vesicles. The mitochondria transfer from immune cells to different cells is associated with physiological and pathological processes, including inflammatory disorders, cardiovascular diseases, diabetes, and cancer. On the other hand, mitochondrial transfer from mesenchymal stem cells, bone marrow-derived stem cells, and adipocytes to immune cells significantly affects their functions. Mitochondrial transfer can prevent exhaustion/senescence in immune cells through intracellular signaling pathways and metabolic reprogramming. Thus, it is emerging as a promising therapeutic strategy for immune system diseases, especially those involving inflammation and autoimmune components. Transferring healthy mitochondria into damaged or dysfunctional cells can restore mitochondrial function, which is crucial for cellular energy production, immune regulation, and inflammation control. Also, mitochondrial transfer may enhance the potential of current therapeutic immune cell-based therapies such as CAR-T cell therapy.

Powering immunity: mitochondrial dynamics in natural killer cells

Natural killer (NK) cells are innate lymphocytes that are crucial for eliminating malignant and infected cells, and have significant therapeutic potential against cancer and viral infections. However, their functionality is often impaired under pathological conditions. Emerging evidence identifies mitochondria as key regulators of NK cell metabolism, fitness, and fate. This review examines how mitochondrial dysfunction impacts on NK cell activity in cancer, viral infections, and inflammatory disorders. We discuss strategies to target mitochondrial architecture, dynamics, and function as potential therapies to restore NK cell fitness. Finally, we highlight unanswered questions and future directions to better understand mitochondrial regulation in NK cells and its implications for therapeutic development.

Dysregulated glutathione metabolism impairs natural killer cell function in patients with acute leukemia

Natural killer (NK) cell function is markedly impaired in patients with acute leukemia, weakening their anti-tumor immune response. However, the mechanisms underlying NK cell dysfunction are not fully understood. Here, we reveal that NK cells from patients with acute leukemia (AL-NK) exhibit significantly reduced intracellular glutathione (GSH) levels, accompanied by disrupted redox homeostasis and increased levels of mitochondrial reactive oxygen species. Flow cytometry and transcriptomic analyses indicate that dysregulated GSH metabolism leads to mitochondrial dysfunction in NK cells, thereby impairing their antileukemic cytotoxicity and proliferative capacity. Notably, supplementation with glutathione reduced ethyl ester (GSHEE)-a GSH precursor-effectively restores GSH levels in AL-NK cells, enhancing mitochondrial activity, oxidative phosphorylation, ATP production, and NK cell-mediated cytotoxicity. Moreover, GSHEE treatment activates the mTOR signaling pathway in NK cells, further promoting their function and proliferation. Overall, our study identifies dysregulated GSH metabolism as a key driver of NK cell dysfunction in acute leukemia and suggests that GSH-based interventions may provide a promising strategy to enhance NK cell-mediated immunotherapies.

AKR1D1 suppresses liver cancer progression by promoting bile acid metabolism-mediated NK cell cytotoxicity

Bile acid metabolism and antitumor immunity are both disrupted during liver cancer progression. However, the complex regulatory relationship between them remains largely unclear. Here, we find that loss of aldo-keto reductase 1D1 (AKR1D1) promotes the accumulation of isolithocholic acid (iso-LCA) through gut microbiome dysregulation, thereby impairing the cytotoxic function of natural killer (NK) cells and leading to the accelerated development of hepatocellular carcinoma (HCC). Mechanistically, AKR1D1 deficiency leads to an increased proportion of Bacteroidetes ovatus (B. ovatus), which breaks down chenodeoxycholic acid (CDCA) into iso-LCA. Moreover, accumulated iso-LCA impairs the antitumor activity of hepatic NK cells in a phosphorylated-CREB1 (p-CREB1)-dependent manner. The potassium-sparing diuretic spironolactone treatment significantly enhances the inhibitory effect of anti-PD1 antibody on HCC progression by targeting iso-LCA-mediated tumor immune escape. Taken together, our results uncover a previously unappreciated link between AKR1D1 and HCC and suggest that targeting iso-LCA produced by B. ovatus might be a promising strategy to activate NK cell cytotoxicity to treat HCC.

Immune dysregulation of decidual NK cells mediated by GRIM19 downregulation contributes to the occurrence of recurrent pregnancy loss

In patients with recurrent pregnancy loss (RPL), excessive activation of decidual natural killer (dNK) cells has been widely observed, yet the precise underlying mechanisms remain to be elucidated. We collected decidual specimens from RPL patients and controls to assess GRIM19 expression, activation phenotype, cytotoxic function, inflammatory cytokine secretion, and mitochondrial homeostasis in dNK cells. Furthermore, we established a GRIM19-knockout NK-92MI cell line and a GRIM19 ± C57BL/6J mouse model to investigate the relationship between GRIM19 downregulation and dNK immune dysregulation, ultimately contributing to pregnancy loss. Decidual NK cells from RPL patients exhibited significantly lower GRIM19 expression, accompanied by abnormal hyperactivation, enhanced cytotoxicity, and abnormal mitochondrial activation. In vitro experiments confirmed that reduced GRIM19 expression significantly potentiated the cytotoxicity and pro-inflammatory cytokine secretion of NK-92MI cells, while also promoting mitochondrial homeostasis imbalance. Mouse model studies corroborated that GRIM19 downregulation triggers NK cell homeostasis imbalance, contributing to the occurrence of pregnancy loss. Downregulation of GRIM19 in dNK cells contributes to RPL through hyperactivation and disruption of mitochondrial homeostasis, emphasizing its potential as a diagnostic and therapeutic target.

Immunometabolism of Innate Immune Cells in Gastrointestinal Cancer

Cancer cells are often described as voracious consumers of nutrients, with glucose frequently cited as a key energy source; however, their metabolic plasticity allows them to adapt and utilize various substrates, including lipids and amino acids, to sustain growth and survival. However, the metabolic demands of immune cells within the tumor microenvironment (TME) are less commonly discussed despite their critical role in shaping the immune response. In this review, we explored the intricate interplay between immunometabolism and innate immunity cells in gastrointestinal cancers. We focused on how metabolic pathways, including glycolysis, fatty acid oxidation, and amino acid metabolism, drive the immunosuppressive functions of myeloid-derived suppressor cells (MDSCs) and tumor-associated neutrophils (TANs), tumor-associated macrophages (TAMs) and innate lymphocyte subsets such as NK cells. These cells contribute to a hostile immune landscape, supporting tumor growth and evasion from immune surveillance in a phenomenon of tumor-derived immunosuppression. Additionally, we investigated the influence of dietary interventions on the metabolic reprogramming of these immune cells, highlighting how nutrition can modulate the TME. Finally, we discussed emerging therapeutic strategies that target metabolic vulnerabilities in MDSCs, TANs, NK cells, and monocytes, offering a novel avenue for enhancing antitumor immunity. By dissecting these mechanisms, we aim to provide insights into how metabolic pathways can be harnessed to improve cancer treatment outcomes. This review underscores the importance of understanding immunometabolism not only as a driver of immune suppression but also as a potential therapeutic target in gastrointestinal cancer.

Neoleukin-2/15-armored CAR-NK cells sustain superior therapeutic efficacy in solid tumors via c-Myc/NRF1 activation

Adoptive transfer of chimeric antigen receptor (CAR)-modified natural killer (NK) cells represents a transformative approach that has significantly advanced clinical outcomes in patients with malignant hematological conditions. However, the efficacy of CAR-NK cells in treating solid tumors is limited by their exhaustion, impaired infiltration and poor persistence in the immunosuppressive tumor microenvironment (TME). As NK cell functional states are associated with IL-2 cascade, we engineered mesothelin-specific CAR-NK cells that secrete neoleukin-2/15 (Neo-2/15), an IL-2Rβγ agonist, to resist immunosuppressive polarization within TME. The adoptively transferred Neo-2/15-armored CAR-NK cells exhibited enhanced cytotoxicity, less exhaustion and longer persistence within TME, thereby having superior antitumor activity against pancreatic cancer and ovarian cancer. Mechanistically, Neo-2/15 provided sustained and enhanced downstream IL-2 receptor signaling, which promotes the expression of c-Myc and nuclear respiratory factor 1 (NRF1) in CAR-NK cells. This upregulation was crucial for maintaining mitochondrial adaptability and metabolic resilience, ultimately leading to increased cytotoxicity and pronounced persistence of CAR-NK cells within the TME. The resistance against TME immunosuppressive polarization necessitated the upregulation of NRF1, which is essential to the augmentative effects elicited by Neo-2/15. Overexpression of NRF1 significantly bolsters the antitumor efficacy of CAR-NK cells both in vitro and in vivo, with increased ATP production. Collectively, Neo-2/15-expressing CAR-NK cells exerts superior antitumor effects by exhaustion-resistance and longer survival in solid tumors.

Resveratrol from Peanut Sprout Extract Promotes NK Cell Activation and Antitumor Activity

Natural killer (NK) cells are innate immune cells that are crucial for anticancer activity and have been developed as an immune cell therapy for leukemia. However, their limited effectiveness against solid tumors has prompted research into methods to enhance NK cell activity through combination therapies. Health supplements capable of boosting immune surveillance against tumor cells are gaining attention owing to their potential benefits. Resveratrol, a stilbenoid produced by several plants including peanuts and grapes, reportedly exerts anticancer effects and can activate immune cells. The peanut sprout extract cultivated with fermented sawdust medium (PSEFS) is rich in resveratrol, leveraging its health benefits in terms of the dry weight of herbal products, thus maximizing the utilization of resveratrol's beneficial properties. Our study compared the efficacy of resveratrol and PSEFS and revealed that PSEFS significantly enhanced NK cell activation compared with an equivalent dose of resveratrol. We investigated the ability of PSEFS to potentiate NK cell anticancer activity, focusing on NK cell survival, tumor cell lysis, and NK cell activation in PSEFS-administered mice. Our findings suggest that PSEFS could be a potential NK cell booster for cancer immunotherapy.

Targeting metabolic dysfunction of CD8 T cells and natural killer cells in cancer

The importance of metabolic pathways in regulating immune responses is now well established, and a mapping of the bioenergetic metabolism of different immune cell types is under way. CD8 T cells and natural killer (NK) cells contribute to cancer immunosurveillance through their cytotoxic functions and secretion of cytokines and chemokines, complementing each other in target recognition mechanisms. Several immunotherapies leverage these cell types by either stimulating their activity or redirecting their specificity against tumour cells. However, the anticancer activity of CD8 T cells and NK cells is rapidly diminished in the tumour microenvironment, closely linked to a decline in their metabolic capacities. Various strategies have been developed to restore cancer immunosurveillance, including targeting bioenergetic metabolism or genetic engineering. This Review provides an overview of metabolic dysfunction in CD8 T cells and NK cells within the tumour microenvironment, highlighting current therapies aiming to overcome these issues.

Adaptation of Natural Killer Cells to Hypoxia: A Review of the Transcriptional, Translational, and Metabolic Processes

As important innate immune cells, natural killer (NK) cells play an essential role in resisting pathogen invasion and eliminating transformed cells. However, the hypoxic microenvironment caused by disease conditions is an important physicochemical factor that impairs NK cell function. With the increasing prominence of NK cells in immunotherapy, there has been a surge of interest in developing biological means through which NK cells may overcome the inhibition caused by hypoxia in disease conditions. Although the effects of hypoxic conditions in shaping the functions of NK cells have been increasingly recognized and investigated, reviews have been scantly. A comprehensive understanding of how NK cells adapt to hypoxia can provide valuable insights into how the functional capacity of NK cells may be restored. This review focuses on the functional alterations of NK cells in response to hypoxia. It delineates the mechanisms by which NK cells adapt to hypoxia at the transcriptional, metabolic, translational levels. Furthermore, given the complexity of the hypoxic microenvironment, we also elucidated the effects of key hypoxic metabolites on NK cells. Finally, this review discusses the current clinical therapies derived from targeting hypoxic NK cells. The study of NK cell adaptation to hypoxia has yielded new insights into immunotherapy. These insights may lead to development of novel strategies to improve the treatment of infectious diseases and cancer.

Mitochondrial alterations and signatures in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer worldwide. Its primary risk factors are chronic liver diseases such as metabolic fatty liver disease, non-alcoholic steatohepatitis, and hepatitis B and C viral infections. These conditions contribute to a specific microenvironment in liver tumors which affects mitochondrial function. Mitochondria are energy producers in cells and are responsible for maintaining normal functions by controlling mitochondrial redox homeostasis, metabolism, bioenergetics, and cell death pathways. HCC involves abnormal mitochondrial functions, such as accumulation of reactive oxygen species, oxidative stress, hypoxia, impairment of the mitochondrial unfolded protein response, irregularities in mitochondrial dynamic fusion/fission mechanisms, and mitophagy. Cell death mechanisms, such as necroptosis, pyroptosis, ferroptosis, and cuproptosis, contribute to hepatocarcinogenesis and play a significant role in chemoresistance. The relationship between mitochondrial dynamics and HCC is thus noteworthy. In this review, we summarize the recent advances in mitochondrial alterations and signatures in HCC and attempt to elucidate its molecular biology. Here, we provide an overview of the mitochondrial processes involved in hepatocarcinogenesis and offer new insights into the molecular pathology of the disease. This may help guide future research focused on improving patient outcomes using innovative therapies.

Decrease of NAD+ Inhibits the Apoptosis of OLP T Cells via Inducing Mitochondrial Fission

Purpose

Oral lichen planus (OLP) is a chronic, immune-mediated inflammatory disease involving T cells. Mitochondrial fission plays a crucial role in T cell fate through structural remodeling. Nicotinamide adenine dinucleotide (NAD+) regulates mitochondrial remodeling and function. This study explored the role of NAD+ in modulating mitochondrial fission and apoptosis in T cells under the OLP immune-inflammatory environment.

Patients and Methods

T cells and plasma were isolated from peripheral blood. Mitochondrial morphology was characterized by transmission electron microscopy and Mito-Tracker staining. OLP plasma-exposed Jurkat T cells were infected with the Drp1 shRNA virus to investigate the role of mitochondrial fission in OLP T cell apoptosis. OLP T cells and OLP plasma-exposed Jurkat T cells were treated with either β-nicotinamide mononucleotide (an NAD+ synthesis precursor) or FK866 (an NAD+ synthesis inhibitor) to assess the effect of NAD+ regulation on mitochondrial remodeling and T cell apoptosis.

Results

OLP T cells exhibited fragmented mitochondria with elevated dynamin-related protein 1 (Drp1) and reduced mitofusin 2 (Mfn2) expression, accompanied by decreased apoptosis. Drp1 knockdown in OLP plasma-exposed Jurkat T cells increased apoptosis and reduced proliferation. NAD+ levels were reduced in both OLP T cells and OLP plasma-treated Jurkat T cells, leading to enhanced mitochondrial fission, decreased mitochondrial membrane potential (MMP) and respiration function, and reduced apoptosis rate. β-nicotinamide mononucleotide supplementation restored NAD+ levels, suppressed mitochondrial fission, improved MMP, and promoted apoptosis in these cells.

Conclusion

Reduced NAD+ levels in OLP T cells enhanced mitochondrial fission and contributed to decreased apoptosis. NAD+ supplementation mitigated these effects, suggesting a potential therapeutic strategy for restoring T cell homeostasis in OLP.

Mesenchymal Stem/Stromal cells in solid tumor Microenvironment: Orchestrating NK cell remodeling and therapeutic insights

Mesenchymal stem/stromal cells (MSCs), originating from normal tissues, possess the capacity to home to tumor sites and differentiate into tumor-associated MSCs (TA-MSCs), which are instrumental in shaping an immunosuppressive milieu within tumors. Natural killer (NK) cells, integral to the innate immune system, are endowed with the ability to eradicate target cells autonomously, serving as an immediate defense against neoplastic growths. Nonetheless, within the tumor microenvironment (TME), NK cells often exhibit a decline in both their numerical presence and functionality. TA-MSCs have been shown to exert profound inhibitory effects on the functions of tumor-infiltrating immune cells, notably NK cells. Understanding the mechanisms by which TA-MSCs contribute to NK cell dysfunction is critical for the advancement of immune surveillance and the enhancement of tumoricidal responses. This review summarizes existing literature on NK cell modulation by TA-MSCs within the TME and proposes innovative strategies to augment antitumor immunity.

Mitochondria in tumor immune surveillance and tumor therapies targeting mitochondria

Mitochondria play a central role in cellular energy production and metabolic regulation, and their function has been identified as a key factor influencing tumor immune responses. This review provides a comprehensive overview of the latest advancements in understanding the role of mitochondria in tumor immune surveillance, covering both innate and adaptive immune responses. Specifically, it outlines how mitochondria influence the function of the tumor immune system, underscoring their crucial role in modulating immune cell behavior to either promote or inhibit tumor development and progression. Additionally, this review highlights emerging drug interventions targeting mitochondria, including novel small molecules with significant potential in cancer therapy. Through an in-depth analysis, it explores how these innovative strategies could improve the efficacy and outlook of tumor treatment.

Targeting mitochondria: restoring the antitumor efficacy of exhausted T cells

Immune checkpoint blockade therapy has revolutionized cancer treatment, but resistance remains prevalent, often due to dysfunctional tumor-infiltrating lymphocytes. A key contributor to this dysfunction is mitochondrial dysfunction, characterized by defective oxidative phosphorylation, impaired adaptation, and depolarization, which promotes T cell exhaustion and severely compromises antitumor efficacy. This review summarizes recent advances in restoring the function of exhausted T cells through mitochondria-targeted strategies, such as metabolic remodeling, enhanced biogenesis, and regulation of antioxidant and reactive oxygen species, with the aim of reversing the state of T cell exhaustion and improving the response to immunotherapy. A deeper understanding of the role of mitochondria in T cell exhaustion lays the foundation for the development of novel mitochondria-targeted therapies and opens a new chapter in cancer immunotherapy.

The hallmarks of cancer immune evasion

According to the widely accepted "three Es" model, the host immune system eliminates malignant cell precursors and contains microscopic neoplasms in a dynamic equilibrium, preventing cancer outgrowth until neoplastic cells acquire genetic or epigenetic alterations that enable immune escape. This immunoevasive phenotype originates from various mechanisms that can be classified under a novel "three Cs" conceptual framework: (1) camouflage, which hides cancer cells from immune recognition, (2) coercion, which directly or indirectly interferes with immune effector cells, and (3) cytoprotection, which shields malignant cells from immune cytotoxicity. Blocking the ability of neoplastic cells to evade the host immune system is crucial for increasing the efficacy of modern immunotherapy and conventional therapeutic strategies that ultimately activate anticancer immunosurveillance. Here, we review key hallmarks of cancer immune evasion under the "three Cs" framework and discuss promising strategies targeting such immunoevasive mechanisms.

Causality Between Immune Cells, Metabolites and Breast Cancer: Mendelian Randomization and Mediation Analysis

Previous studies have shown that immune cells and metabolites are associated with the development of breast cancer, but the causal relationship is unclear. We use Mendelian randomization (MR) to explore potential connections between them. Based on two sample MR studies, we evaluated the causal relationship between 731 immune cell traits, 1400 metabolites and breast cancer. In addition, we evaluated the mediating role of metabolites between immune cells and breast cancer using two-step MR Studies. Pooled GWAS data on 731 immune cell traits (n = 3757), 1400 metabolites (n = 8299) and breast cancer (ncase = 122,977, ncontrol = 105,974) were obtained from publicly available authoritative databases. We mainly used inverse variance weighted (IVW) method combined with Bayesian weighted MR (BWMR), MR-Egger, weighted median, simple mode, and weighted mode methods. The results of MR Studies showed that 3 immune cells and 15 metabolites were associated with an increased risk of breast cancer. 8 immune cells and 11 metabolites are associated with a reduced risk of breast cancer. Mediating MR Analysis showed that 6 metabolites, Tricosanoyl sphingomyelin (d18:1/23:0) levels(Mediated proportion:17.5%), N-palmitoyl-heptadecasphingosine (d17:1/16:0) levels(8.74%), Inosine 5'-monophosphate (IMP) to phosphate ratio(11.3%), Glutamine to asparagine ratio(5.43%), Oleoyl-linoleoyl-glycerol (18:1/18:2) [2] levels(8.48%), and Sphinganine-1-phosphate levels(8.68%), were found to mediate the relationship between immune cells and breast cancer. Our study reveals a potential causal relationship among multiple immune cells traits, metabolites, and breast cancer. It provides valuable clues and potential therapeutic targets for breast cancer biomarker discovery and breast cancer treatment.

Metabolic programs drive function of therapeutic NK cells in hypoxic tumor environments

Limited oxygen (hypoxia) in solid tumors poses a challenge to successful immunotherapy with natural killer (NK) cells. NK cells have impaired cytotoxicity when cultured in hypoxia (1% oxygen) but not physiologic (>5%) or atmospheric oxygen (20%). We found that changes to cytotoxicity were regulated at the transcriptional level and accompanied by metabolic dysregulation. Dosing with interleukin-15 (IL-15) enhanced NK cell cytotoxicity in hypoxia, but preactivation with feeder cells bearing IL-21 and 4-1BBL was even better. Preactivation resulted in less perturbed metabolism in hypoxia; greater resistance to oxidative stress; and no hypoxia-induced loss of transcription factors (T-bet and Eomes), activating receptors, adhesion molecules (CD2), and cytotoxic proteins (TRAIL and FasL). There remained a deficit in CD122/IL-2Rβ when exposed to hypoxia, which affected IL-15 signaling. However, tri-specific killer engager molecules that deliver IL-15 in the context of anti-CD16/FcγRIII were able to bypass this deficit, enhancing cytotoxicity of both fresh and preactivated NK cells in hypoxia.

Farnesyl pyrophosphate potentiates dendritic cell migration in autoimmunity through mitochondrial remodelling

Cellular metabolism modulates dendritic cell (DC) maturation and activation. Migratory dendritic cells (mig-DCs) travelling from the tissues to draining lymph nodes (dLNs) are critical for instructing adaptive immune responses. However, how lipid metabolites influence mig-DCs in autoimmunity remains elusive. Here, we demonstrate that farnesyl pyrophosphate (FPP), an intermediate of the mevalonate pathway, accumulates in mig-DCs derived from mice with systemic lupus erythematosus (SLE). FPP promotes mig-DC survival and germinal centre responses in the dLNs by coordinating protein geranylgeranylation and mitochondrial remodelling. Mechanistically, FPP-dependent RhoA geranylgeranylation promotes mitochondrial fusion and oxidative respiration through mitochondrial RhoA-MFN interaction, which subsequently facilitates the resolution of endoplasmic reticulum stress in mig-DCs. Simvastatin, a chemical inhibitor of the mevalonate pathway, restores mitochondrial function in mig-DCs and ameliorates systemic pathogenesis in SLE mice. Our study reveals a critical role for FPP in dictating mig-DC survival by reprogramming mitochondrial structure and metabolism, providing new insights into the pathogenesis of DC-dependent autoimmune diseases.

Targeting TGR5 to mitigate liver fibrosis: Inhibition of hepatic stellate cell activation through modulation of mitochondrial fission

Chronic hepatitis B virus (HBV) infection continues to be a prominent cause of liver fibrosis and end-stage liver disease in China, necessitating the development of effective therapeutic strategies. This study investigated the potential of targeting TGR5 to alleviate liver fibrosis by impeding the activation of hepatic stellate cells (HSCs), which play a pivotal role in fibrotic progression. Using the human hepatic stellate cell line LX-2 overexpressing hepatitis B virus X protein (HBX), this study revealed that TGR5 activation through INT-777 inhibits HBX-induced LX-2 cell activation, thereby ameliorating liver fibrosis, which is associated with the attenuation of mitochondrial fission and introduces a novel regulatory pathway in liver fibrosis. Additional experiments with mitochondrial fission inducers and inhibitors confirm the crucial role of mitochondrial dynamics in TGR5-mediated effects. In vivo studies using TGR5 knockout mice substantiate these findings, demonstrating exacerbated fibrosis in the absence of TGR5 and its alleviation with the mitochondrial fission inhibitor Mdivi-1. Overall, this study provides insights into TGR5-mediated regulation of liver fibrosis through the modulation of mitochondrial fission in HSCs, suggesting potential therapeutic strategies for liver fibrosis intervention.

Prognostic value and immunomodulatory role of DNM1L in gastric adenocarcinoma

Background

Mitochondrial fusion and fission are critical for the morphology and function of cells. DNM1L encodes dynamin-related protein 1 (DRP1), a key protein mediating mitochondrial fission, which is upregulated in a variety of cancers and is strongly associated with tumorigenesis. We aim to investigate the relationship between DNM1L and the prognosis of gastric cancer, as well as to explore the function and mechanism of DNM1L in gastric cancer (GC).

Materials and methods

In this study, we analyzed the expression differences of DNM1L in gastric cancer tissues and paracancerous tissues using The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO) database. This was followed by validation through tissue microarrays. We then utilized the cohort information from these microarrays to explore the relationship between DNM1L expression and gastric cancer prognosis. Furthermore, we conducted enrichment analysis to investigate the function and mechanisms of DNM1L in gastric cancer, and lastly, we performed immune cell infiltration analysis using the CIBERSORT algorithm.

Results

We discovered that the expression of DNM1L is elevated in GC tissues. TCGA data showed that the overexpression of DNM1L was positively correlated with the T-stage of GC but not with lymph node metastasis, which was also corroborated by our immunohistochemistry experiments. Based on the Kaplan-Meier curves, the high DNM1L expression was remarkably correlated with poor overall survival in patients with GC. In addition, results of COX regression analysis indicated that high DNM1L expression was an independent prognostic factor in patients with GC. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene set enrichment analysis (GSEA) showed that DNM1L was closely associated with multiple signaling pathways and immune responses. CIBERSORT analysis indicated that increased DNM1L expression may affect the infiltration of immune cells in the tumor microenvironment.

Conclusion

The results of this study indicate that DNM1L is upregulated in gastric cancer (GC) and positively correlates with the T-stage and poor prognosis of GC patients, and it plays an important role in tumor immune infiltration.

Impact of mitochondrial dysfunction on the antitumor effects of immune cells

Mitochondrial dysfunction, a hallmark of immune cell failure, affects the antitumor effects of immune cells through metabolic reprogramming, fission, fusion, biogenesis, and immune checkpoint signal transduction of mitochondria. According to researchers, restoring damaged mitochondrial function can enhance the efficacy of immune cells. Nevertheless, the mechanism of mitochondrial dysfunction in immune cells in patients with cancer is unclear. In this review, we recapitulate the impact of mitochondrial dysfunction on the antitumor effects of T cells, natural killer cells, dendritic cells, and tumor-associated macrophage and propose that targeting mitochondria can provide new strategies for antitumor therapy.

Mitochondrial regulation in the tumor microenvironment: targeting mitochondria for immunotherapy

Mitochondrial regulation plays a crucial role in cancer immunity in the tumor microenvironment (TME). Infiltrating immune cells, including T cells, natural killer (NK) cells, and macrophages, undergo mitochondrial metabolic reprogramming to survive the harsh conditions of the TME and enhance their antitumor activity. On the other hand, immunosuppressive cells like myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), mast cells, and tumor-associated macrophages (TAMs) rely on mitochondrial regulation to maintain their function as well. Additionally, mitochondrial regulation of cancer cells facilitates immune evasion and even hijacks mitochondria from immune cells to enhance their function. Recent studies suggest that targeting mitochondria can synergistically reduce cancer progression, especially when combined with traditional cancer therapies and immune checkpoint inhibitors. Many mitochondrial-targeting drugs are currently in clinical trials and have the potential to enhance the efficacy of immunotherapy. This mini review highlights the critical role of mitochondrial regulation in cancer immunity and provides lists of mitochondrial targeting drugs that have potential to enhance the efficacy of cancer immunotherapy.

Mechanisms of HIF1A-mediated immune evasion in gastric cancer and the impact on therapy resistance

BACKGROUND

The high prevalence and detrimental effects on patient outcomes make gastric cancer (GC) a significant health issue that persists internationally. Existing treatment modalities exhibit limited efficacy, prompting the exploration of immune checkpoint inhibitors as a novel therapeutic approach. However, resistance to immunotherapy poses a significant challenge in GC management, necessitating a profound grasp of the intrinsic molecular pathways.

METHODS

This study focuses on investigating the immunosuppressive mechanisms of quiescent cancer cells (QCCs) in GC, particularly their resistance to T-cell-mediated immune responses. Utilizing mouse models, gene editing techniques, and transcriptome sequencing, we aim to elucidate the interactions between QCCs, immune cells, and key regulatory factors like HIF1A. Functional enrichment analysis will further underscore the role of glycolysis-related genes in mediating immunosuppression by QCCs.

RESULTS

The cancer cells that survived GC treated with T-cell therapy lost their proliferative ability. QCCs, as the main resistance force to immunotherapy, exhibit stronger resistance to CD8+ T-cell attack and possess higher cancer-initiating potential. Single-cell sequencing analysis revealed that the microenvironment in the QCCs region harbors more M2-type tumor-associated macrophages and fewer T cells. This microenvironment in the QCCs region leads to the downregulation of T-cell immune activation and alters macrophage metabolic function. Transcriptome sequencing of QCCs identified upregulated genes related to chemo-resistance, hypoxia, and glycolysis. In vitro cell experiments illustrated that HIF1A promotes the transcription of glycolysis-related genes, and silencing HIF1A in QCCs enhances T-cell proliferation and activation in co-culture systems, induces apoptosis in QCCs, and increases QCCs' sensitivity to immune checkpoint inhibitors. In vivo, animal experiments showed that silencing HIF1A in QCCs can inhibit GC growth and metastasis.

CONCLUSION

Unraveling the molecular mechanisms by which QCCs resist T-cell-mediated immune responses through immunosuppression holds promising implications for refining treatment strategies and enhancing patient outcomes in GC. By delineating these intricate interactions, this study contributes crucial insights into precision medicine and improved therapeutic outcomes in GC management.

CAR-T and CAR-NK as cellular cancer immunotherapy for solid tumors

In the past decade, chimeric antigen receptor (CAR)-T cell therapy has emerged as a promising immunotherapeutic approach for combating cancers, demonstrating remarkable efficacy in relapsed/refractory hematological malignancies in both pediatric and adult patients. CAR-natural killer (CAR-NK) cell complements CAR-T cell therapy by offering several distinct advantages. CAR-NK cells do not require HLA compatibility and exhibit low safety concerns. Moreover, CAR-NK cells are conducive to "off-the-shelf" therapeutics, providing significant logistic advantages over CAR-T cells. Both CAR-T and CAR-NK cells have shown consistent and promising results in hematological malignancies. However, their efficacy against solid tumors remains limited due to various obstacles including limited tumor trafficking and infiltration, as well as an immuno-suppressive tumor microenvironment. In this review, we discuss the recent advances and current challenges of CAR-T and CAR-NK cell immunotherapies, with a specific focus on the obstacles to their application in solid tumors. We also analyze in depth the advantages and drawbacks of CAR-NK cells compared to CAR-T cells and highlight CAR-NK CAR optimization. Finally, we explore future perspectives of these adoptive immunotherapies, highlighting the increasing contribution of cutting-edge biotechnological tools in shaping the next generation of cellular immunotherapy.

Preparation and evaluation of gastrodin microsphere-loaded Gastrodia elata polysaccharides composite hydrogel on UVB-induced skin damage in vitro and in vivo

Skin damage from sun exposure is a common issue among outdoor workers and is primarily caused by ultraviolet rays. Upon absorption of these rays, the skin will experience inflammation and cell apoptosis. This study explored the concept of 'Combination of medicine and adjuvant' by utilizing Gastrodia elata polysaccharide, a key component of Gastrodia elata Bl.‌, to develop a new hydrogel material. Oxidized Gastrodia elata polysaccharide (OGEP) and carboxymethyl chitosan (CMCS) was use to prepare a biocompatible, biodegradable and self-healing hydrogel OGEP/CMCS (OC). And this hydrogel was further loaded with Gastrodin-containing microspheres (GAS/GEL) to create GAS/GEL/OGEP/CMCS (GGOC) hydrogel. Characterization studies revealed that OC and GGOC hydrogels exhibited favorable mechanical properties, antioxidant activity and biocompatibility. The experiments showed that OC and GGOC hydrogels could regulate mitochondrial membrane potential, prevent mitochondrial breakage, inhibit proinflammatory factors, prevent NF-κB protein activation and regulate apoptosis-related pathways. This study highlighted the application potential of Gastrodia elata polysaccharide as a 'Combination of medicine and adjuvant' and the anti-UVB damage effect of the prepared hydrogel.

Targeting DNM1L/DRP1-FIS1 axis inhibits high-grade glioma progression by impeding mitochondrial respiratory cristae remodeling

BACKGROUND

The dynamics of mitochondrial respiratory cristae (MRC) and its impact on oxidative phosphorylation (OXPHOS) play a crucial role in driving the progression of high-grade glioma (HGG). However, the underlying mechanism remains unclear.

METHODS

In the present study, we employed machine learning-based transmission electron microscopy analysis of 7141 mitochondria from 54 resected glioma patients. Additionally, we conducted bioinformatics analysis and multiplex immunohistochemical (mIHC) staining of clinical glioma microarrays to identify key molecules involved in glioma. Subsequently, we modulated the expression levels of mitochondrial dynamic-1-like protein (DNM1L/DRP1), and its two receptors, mitochondrial fission protein 1 (FIS1) and mitochondrial fission factor (MFF), via lentiviral transfection to further investigate the central role of these molecules in the dynamics of glioblastoma (GBM) cells and glioma stem cells (GSCs). We then evaluated the potential impact of DNM1L/DRP1, FIS1, and MFF on the proliferation and progression of GBM cells and GSCs using a combination of CCK-8 assay, Transwell assay, Wound Healing assay, tumor spheroid formation assay and cell derived xenograft assay employing NOD/ShiLtJGpt-Prkdcem26Cd52Il2rgem26Cd22/Gpt (NCG) mouse model. Subsequently, we validated the ability of the DNM1L/DRP1-FIS1 axis to remodel MRC structure through mitophagy by utilizing Seahorse XF analysis technology, mitochondrial function detection, MRC abundance detection and monitoring dynamic changes in mitophagy.

RESULTS

Our findings revealed that compared to low-grade glioma (LGG), HGG exhibited more integrated MRC structures. Further research revealed that DNM1L/DRP1, FIS1, and MFF played pivotal roles in governing mitochondrial fission and remodeling MRC in HGG. The subsequent validation demonstrated that DNM1L/DRP1 exerts a positive regulatory effect on FIS1, whereas the interaction between MFF and FIS1 demonstrates a competitive inhibition relationship. The down-regulation of the DNM1L/DRP1-FIS1 axis significantly impaired mitophagy, thereby hindering the remodeling of MRC and inhibiting OXPHOS function in glioma, ultimately leading to the inhibition of its aggressive progression. In contrast, MFF exerts a contrasting effect on MRC integrity, OXPHOS activity, and glioma progression.

CONCLUSIONS

This study highlights that the DNM1L/DRP1-FIS1 axis stabilizes MRC structures through mitophagy in HGG cells while driving their OXPHOS activity ultimately leading to robust disease progression. The inhibition of the DNM1L/DRP1-FIS1 axis hinders MRC remodeling and suppresses GBM progression. We propose that down-regulation of the DNM1L/DRP1-FIS1 axis could be a potential therapeutic strategy for treating HGG.

Engineered Platelet for In Situ Natural Killer Cell Activation to Inhibit Tumor Recurrence

Natural killer (NK) cells offer profound advantages against tumor recurrence due to their unique immunological behavior. NK cell therapies associated with the antibody-dependent cell-mediated cytotoxicity (ADCC) effect have made remarkable progress while being limited by insufficient antibody binding and the exhausted state of NK cells in the postsurgical immunosuppressive microenvironment. Leveraging the adherence of PLT to tumor cells, we developed an exogenously implanted platelet (PLT)-based NK cell-driven system (PLT-IgG-IL15) to improve the identifiability of residual tumors with IgG antibody labeling for NK cells catching and engaging, which consequently restored the ADCC effect and promoted the recovery of their killing function. Furthermore, interleukin-15 (IL-15) participated in the augmentation of NK cell function. Collectively, PLT-IgG-IL15 served as an NK cell tumor cell engager as well as an NK cell charger, achieving a <40% recurrence rate in mouse tumor models.

Innate immune cells in tumor microenvironment: A new frontier in cancer immunotherapy

Innate immune cells, crucial in resisting infections and initiating adaptive immunity, play diverse and significant roles in tumor development. These cells, including macrophages, granulocytes, dendritic cells (DCs), innate lymphoid cells, and innate-like T cells, are pivotal in the tumor microenvironment (TME). Innate immune cells are crucial components of the TME, based on which various immunotherapy strategies have been explored. Immunotherapy strategies, such as novel immune checkpoint inhibitors, STING/CD40 agonists, macrophage-based surface backpack anchoring, ex vivo polarization approaches, DC-based tumor vaccines, and CAR-engineered innate immune cells, aim to enhance their anti-tumor potential and counteract cancer-induced immunosuppression. The proximity of innate immune cells to tumor cells in the TME also makes them excellent drug carriers. In this review, we will first provide a systematic overview of innate immune cells within the TME and then discuss innate cell-based therapeutic strategies. Furthermore, the research obstacles and perspectives within the field will also be addressed.

Immunometabolism in cancer: A journey into innate and adaptive cells

In recent years, mostly spanning the past decade, the concept of immunometabolism has ushered with a novel perspective on carcinogenesis, tumor progression, and tumor response to therapy. It has become clear that the metabolic state of immune cells plays a significant role in shaping their antitumor or protumor activities within the cancer microenvironment. Consequently, the examination of tumor metabolic heterogeneity, including an exploration of immunometabolism, proves indispensable for enhancing prognostic tools and advancing the quest for personalized treatments. Here we have delved into how metabolic reprogramming profoundly influences the acquisition and maintenance of functional states, spanning from effector and cytotoxic profiles to regulatory and immunosuppressive phenotypes in both innate and adaptive immunity. These alterations wield considerable influence over tumor evolution and affect the outcome of cancer. Furthermore, we explore some of the cellular signaling mechanisms that underpin the metabolic and phenotypic flexibility of immune cells in response to external stimuli.

Sepsis induced dysfunction of liver type 1 innate lymphoid cells

BACKGROUND

Sepsis is a life-threatening condition triggered by uncontrolled immune responses to infection, leading to widespread inflammation, tissue damage, organ dysfunction, and potentially death. The liver plays a crucial role in the immune response during sepsis, serving as a major site for immune cell activation and cytokine production. Liver type 1 innate lymphoid cells (ILCs) consist of NK cells and ILC1s. They maintain the local immune microenvironment by directly eliminating target cells and secreting cytokines. However, the specific roles and pathological changes of liver-resident NK cells and ILC1s during sepsis remain poorly understood.

RESULTS

This study aims to investigate the pathological changes of NK cells and ILC1s, which might contribute the dysfunction of liver. Sepsis mouse model was established by cecal ligation and puncture (CLP). Mouse immune cells from liver were isolated, and the surface makers, gene expression profiles, cytokine response and secretion, and mitochondrial function of NK (Natural Killer) cells and ILC1s (Innate Lymphoid Cell 1) were analyzed. A significant decrease in the number of mature NK cells was observed in the liver after CLP. Furthermore, the secretion of interferon-gamma (IFN-γ) was found to be reduced in spleen and liver NK cells when stimulated by IL-18. Mitochondrial activities in both liver NK cells and ILC1 were found to be increased during sepsis, suggesting an enhanced metabolic response in these cells to combat the infection. However, despite this heightened activity, liver NK cells exhibited a decreased level of cytotoxicity, which might impact their ability to target infected cells effectively. RNA sequencing supported and provided the potential mechanisms for the proinflammatory effects and exhaustion like phenotypes of liver NK cells.

CONCLUSIONS

Sepsis induces dysfunction and exhaustion-like phenotypes in liver NK cells and ILC1, which might further impair other immune cells and represent a potential therapeutic target for sepsis.

Identifying prognostic biomarkers in oral squamous cell carcinoma: an integrated single-cell and bulk RNA sequencing study on mitophagy-related genes

Oral squamous cell carcinoma (OSCC) has an extremely poor prognosis. Recent studies have suggested that mitophagy-related genes (MRGs) are closely correlated with the development and occurrence of cancer, but the role they play in oral cancer has not yet been explained.We conducted a comprehensive analysis of integrated single-cell and bulk RNA sequencing (RNA-seq) data retrieved from Gene Expression Omnibus (GEO) datasets and The Cancer Genome Atlas (TCGA) database. Multiple methods were combined to provide a comprehensive understanding of the genetic expression patterns and biology of OSCC, such as analysis of pseudotime series, CellChat cell communication, immune infiltration, Gene Ontology (GO), LASSO Cox regression, gene set variation analysis (GSVA), Kyoto Encyclopedia of Genes and Genomes (KEGG), gene set enrichment analysis (GSEA), Tumor Mutation Burden (TMB) and drug sensitivity assessments. The findings of this study demonstrated significantly greater activity of MRGs in NK cells than in other cells in OSCC. A reliable prognostic model was developed using 12 candidate genes strongly associated with mitochondrial autophagy. T stage, N stage and risk score were revealed as independent prognostic factors. Distinctively enriched pathways and immune cells were observed in different risk groups. Notably, low-risk patients were more responsive to chemotherapy. In addition, a nomogram model with excellent predictive ability was established by combining the risk scores and clinical features. The activity of MRGs suggest the potential for the development of new targeted therapies. The construction of a robust prognostic model also provides reference value for individualized prediction and clinical decision-making in patients with OSCC.

GPR50 regulates neuronal development as a mitophagy receptor

Neurons rely heavily on high mitochondrial metabolism to provide sufficient energy for proper development. However, it remains unclear how neurons maintain high oxidative phosphorylation (OXPHOS) during development. Mitophagy plays a pivotal role in maintaining mitochondrial quality and quantity. We herein describe that G protein-coupled receptor 50 (GPR50) is a novel mitophagy receptor, which harbors the LC3-interacting region (LIR) and is required in mitophagy under stress conditions. Although it does not localize in mitochondria under normal culturing conditions, GPR50 is recruited to the depolarized mitochondrial membrane upon mitophagy stress, which marks the mitochondrial portion and recruits the assembling autophagosomes, eventually facilitating the mitochondrial fragments to be engulfed by the autophagosomes. Mutations Δ502-505 and T532A attenuate GPR50-mediated mitophagy by disrupting the binding of GPR50 to LC3 and the mitochondrial recruitment of GPR50. Deficiency of GPR50 causes the accumulation of damaged mitochondria and disrupts OXPHOS, resulting in insufficient ATP production and excessive ROS generation, eventually impairing neuronal development. GPR50-deficient mice exhibit impaired social recognition, which is rescued by prenatal treatment with mitoQ, a mitochondrially antioxidant. The present study identifies GPR50 as a novel mitophagy receptor that is required to maintain mitochondrial OXPHOS in developing neurons.

Prdm1 positively regulates liver Group 1 ILCs cancer immune surveillance and preserves functional heterogeneity

Group 1 innate lymphoid cells (ILCs) comprise conventional natural killer (cNK) cells and type 1 innate lymphoid cells (ILC1s). The main functions of liver cNK cells and ILC1s not only include directly killing target cells but also regulating local immune microenvironment of the liver through the secretion of cytokines. Uncovering the intricate mechanisms by which transcriptional factors regulate and influence the functions of liver cNK cells and ILC1s, particularly within the context of liver tumors, presents a significant opportunity to amplify the effectiveness of immunotherapies against liver malignancies. Using Ncr1-drived conditional knockout mouse model, our study reveals the regulatory role of Prdm1 in shaping the composition and maturation of cNK cells. Although Prdm1 did not affect the killing function of cNK cells in an in vivo cytotoxicity model, a significant increase in cancer metastasis was observed in Prdm1 knockout mice. Interferon-gamma (IFN-γ), granzyme B, and perforin secretion decreased significantly in Prdm1-deficient cNK cells and liver ILC1s. Single-cell RNA sequencing (scRNA-seq) data also provided evidences that Prdm1 maintains functional subsets of cNK cells and liver ILC1s and facilitates communications between cNK cells, liver ILC1s, and macrophages. The present study unveiled a novel regulatory mechanism of Prdm1 in cNK cells and liver ILC1s, showing promising potential for developing innovative immune therapy strategies against liver cancer.

Decrease in UCP1 by sustained high lipid promotes NK cell necroptosis to exacerbate nonalcoholic liver fibrosis

Uncoupling protein 1 (UCP1) catalyzes the leak of protons across the mitochondrial inner membrane for thermogenesis. Compromised NK cell activity is involved in the occurrence of nonalcoholic liver fibrosis. Here, decreased UCP1 in NK cells was identified in patients with advanced nonalcoholic fatty liver disease. Although no obvious changes were observed in the NK cells of physiologic UCP1-/- mice (8-10 weeks old), impaired NK cell bioactivity was shown in methionine-choline-diet (MCD)-fed UCP1-/- mice and involved in the acerbation of nonalcoholic steatohepatitis (NASH) progress to liver fibrosis. Moreover, UCP1-deficient NK cells were responsible for the aggravation of liver fibrosis, as confirmed in MCD-fed UCP1flox/flox-NCR1cre mice. Acerbation of liver fibrosis was also seen in wild-type mice when their endogenous NK cells were replaced with UCP1-/- NK cells. Transcriptions of mitophagy-associated molecules in UCP1-/- NK cells were enhanced according to RNA-seq. Electron microscopic results showed mitochondrial injuries and autophagic vesicles in MCD-fed NKWT cells, PA-treated NKWT cells, or physiologic NKKO cells. However, the co-existence of UCP1 deficiency and high lipid can synergistically induce NK cell necroptosis via DRP1S616 accompanied with reduced mitophagy. Finally, The UCP1 in NK cells was downregulated when treated by sustained high PA (600 μM) via the PPARγ/ATF2 axis. Thus, persistent high-lipid treatment not only decreases UCP1 expression but also combines with reduced UCP1 to promote NK cell necroptosis, and it is involved in NASH progression to fibrosis.

Proteomic and phenotypic characteristics of memory-like natural killer cells for cancer immunotherapy

BACKGROUND

Human and mouse natural killer (NK) cells have been shown to develop memory-like function after short-term exposure to the cocktail of IL-12/15/18 or to overnight co-culture with some tumor cell lines. The resulting cells retain enhanced lytic ability for up to 7 days as well as after cryopreservation, and memory-like NK cells (mlNK) have been shown to induce complete remissions in patients with hematological malignancies. No single phenotype has been described for mlNK and the physiological changes induced by the short-term cytokine or tumor-priming which are responsible for these enhanced functions have not been fully characterized. Here, we have generated mlNK by cytokine and tumor-priming to find commonalities to better define the nature of NK cell "memory" in vitro and, for the first time, in vivo.

METHODS

We initiated mlNK in vitro from healthy donors with cytokines (initiated cytokine-induced memory-like (iCIML)-NK) and by tumor priming (TpNK) overnight and compared them by high-dimensional flow cytometry, proteomic and metabolomic profiling. As a potential mechanism of enhanced cytolytic function, we analyzed the avidity of binding of the mlNK to NK-resistant tumors (z-Movi). We generated TpNK from healthy donors and from cancer patients to determine whether mlNK generated by interaction with a single tumor type could enhance lytic activity. Finally, we used a replication-incompetent tumor cell line (INKmune) to treat patients with myeloid leukaemias to potentiate NK cell function in vivo.

RESULTS

Tumor-primed mlNK from healthy donors and patients with cancer showed increased cytotoxicity against multiple tumor cell lines in vitro, analogous to iCIML-NK cells. Multidimensional cytometry identified distinct memory-like profiles of subsets of cells with memory-like characteristics; upregulation of CD57, CD69, CD25 and ICAM1. Proteomic profiling identified 41 proteins restricted to mlNK cells and we identified candidate molecules for the basis of NK memory which can explain how mlNK overcome inhibition by resistant tumors. Finally, of five patients with myelodysplastic syndrome or refractory acute myeloid leukemia treated with INKmune, three responded to treatment with measurable increases in NK lytic function and systemic cytokines.

CONCLUSIONS

NK cell "memory" is a physiological state associated with resistance to MHC-mediated inhibition, increased metabolic function, mitochondrial fitness and avidity to NK-resistant target cells.

The ω-3 Polyunsaturated Fatty Acid Docosahexaenoic Acid Enhances NK-Cell Antitumor Effector Functions

ω-3 polyunsaturated fatty acids (PUFA) are known to directly repress tumor development and progression. In this study, we explored whether docosahexaenoic acid (DHA), a type of ω-3 PUFA, had an immunomodulatory role in inhibiting tumor growth in immunocompetent mice. The number of natural killer (NK) cells but not the number of T or B cells was decreased by DHA supplementation in various tissues under physiologic conditions. Although the frequency and number of NK cells were comparable, IFNγ production by NK cells in both the spleen and lung was increased in DHA-supplemented mice in the mouse B16F10 melanoma tumor model. Single-cell RNA sequencing revealed that DHA promoted effector function and oxidative phosphorylation in NK cells but had no obvious effects on other immune cells. Using Rag2-/- mice and NK-cell depletion by PK136 antibody injection, we demonstrated that the suppression of B16F10 melanoma tumor growth in the lung by DHA supplementation was dependent mainly on NK cells. In vitro experiments showed that DHA directly enhanced IFNγ production, CD107a expression, and mitochondrial oxidative phosphorylation (OXPHOS) activity and slightly increased proliferator-activated receptor gamma coactivator-1α (PGC-1α) protein expression in NK cells. The PGC-1α inhibitor SR-18292 in vitro and NK cell-specific knockout of PGC-1α in mice reversed the antitumor effects of DHA. In summary, our findings broaden the current knowledge on how DHA supplementation protects against cancer growth from the perspective of immunomodulation by upregulating PGC-1α signaling-mediated mitochondrial OXPHOS activity in NK cells.

NK cells as powerful therapeutic tool in cancer immunotherapy

BACKGROUND

Natural killer (NK) cells have gained considerable attention and hold great potential for their application in tumor immunotherapy. This is mainly due to their MHC-unrestricted and pan-specific recognition capabilities, as well as their ability to rapidly respond to and eliminate target cells. To artificially generate therapeutic NK cells, various materials can be utilized, such as peripheral blood mononuclear cells (PBMCs), umbilical cord blood (UCB), induced pluripotent stem cells (iPSCs), and NK cell lines. Exploiting the therapeutic potential of NK cells to treat tumors through in vivo and in vitro therapeutic modalities has yielded positive therapeutic results.

CONCLUSION

This review provides a comprehensive description of NK cell therapeutic approaches for tumors and discusses the current problems associated with these therapeutic approaches and the prospects of NK cell therapy for tumors.

Mitochondrial quality control in human health and disease

Mitochondria, the most crucial energy-generating organelles in eukaryotic cells, play a pivotal role in regulating energy metabolism. However, their significance extends beyond this, as they are also indispensable in vital life processes such as cell proliferation, differentiation, immune responses, and redox balance. In response to various physiological signals or external stimuli, a sophisticated mitochondrial quality control (MQC) mechanism has evolved, encompassing key processes like mitochondrial biogenesis, mitochondrial dynamics, and mitophagy, which have garnered increasing attention from researchers to unveil their specific molecular mechanisms. In this review, we present a comprehensive summary of the primary mechanisms and functions of key regulators involved in major components of MQC. Furthermore, the critical physiological functions regulated by MQC and its diverse roles in the progression of various systemic diseases have been described in detail. We also discuss agonists or antagonists targeting MQC, aiming to explore potential therapeutic and research prospects by enhancing MQC to stabilize mitochondrial function.

Tumor-associated NK cells drive MDSC-mediated tumor immune tolerance through the IL-6/STAT3 axis

Apart from their killer identity, natural killer (NK) cells have integral roles in shaping the tumor microenvironment. Through immune gene deconvolution, the present study revealed an interplay between NK cells and myeloid-derived suppressor cells (MDSCs) in nonresponders of immune checkpoint therapy. Given that the mechanisms governing the outcome of NK cell-to-myeloid cell interactions remain largely unknown, we sought to investigate the cross-talk between NK cells and suppressive myeloid cells. Upon contact with tumor-experienced NK cells, monocytes and neutrophils displayed increased expression of MDSC-related suppressive factors along with increased capacities to suppress T cells. These changes were accompanied by impaired antigen presentation by monocytes and increased ER stress response by neutrophils. In a cohort of patients with sarcoma and breast cancer, the production of interleukin-6 (IL-6) by tumor-infiltrating NK cells correlated with S100A8/9 and arginase-1 expression by MDSCs. At the same time, NK cell-derived IL-6 was associated with tumors with higher major histocompatibility complex class I expression, which we further validated with b2m-knockout (KO) tumor mice models. Similarly in syngeneic wild-type and IL-6 KO mouse models, we then demonstrated that the accumulation of MDSCs was influenced by the presence of such regulatory NK cells. Inhibition of the IL-6/signal transducer and activator of transcription 3 (STAT3) axis alleviated suppression of T cell responses, resulting in reduced tumor growth and metastatic dissemination. Together, these results characterize a critical NK cell-mediated mechanism that drives the development of MDSCs during tumor immune escape.

Metabolic adaptations determine whether natural killer cells fail or thrive within the tumor microenvironment

Natural Killer (NK) cells are a top contender in the development of adoptive cell therapies for cancer due to their diverse antitumor functions and ability to restrict their activation against nonmalignant cells. Despite their success in hematologic malignancies, NK cell-based therapies have been limited in the context of solid tumors. Tumor cells undergo various metabolic adaptations to sustain the immense energy demands that are needed to support their rapid and uncontrolled proliferation. As a result, the tumor microenvironment (TME) is depleted of nutrients needed to fuel immune cell activity and contains several immunosuppressive metabolites that hinder NK cell antitumor functions. Further, we now know that NK cell metabolic status is a main determining factor of their effector functions. Hence, the ability of NK cells to withstand and adapt to these metabolically hostile conditions is imperative for effective and sustained antitumor activity in the TME. With this in mind, we review the consequences of metabolic hostility in the TME on NK cell metabolism and function. We also discuss tumor-like metabolic programs in NK cell induced by STAT3-mediated expansion that adapt NK cells to thrive in the TME. Finally, we examine how other approaches can be applied to enhance NK cell metabolism in tumors.

Mitochondrial dynamics, quality control, and mtDNA in alcohol-associated liver disease and liver cancer

Mitochondria are intracellular organelles responsible for energy production, glucose and lipid metabolism, cell death, cell proliferation, and innate immune response. Mitochondria are highly dynamic organelles that constantly undergo fission, fusion, and intracellular trafficking, as well as degradation and biogenesis. Mitochondrial dysfunction has been implicated in a variety of chronic liver diseases including alcohol-associated liver disease, metabolic dysfunction-associated steatohepatitis, and HCC. In this review, we provide a detailed overview of mitochondrial dynamics, mitophagy, and mitochondrial DNA-mediated innate immune response, and how dysregulation of these mitochondrial processes affects the pathogenesis of alcohol-associated liver disease and HCC. Mitochondrial dynamics and mitochondrial DNA-mediated innate immune response may thereby represent an attractive therapeutic target for ameliorating alcohol-associated liver disease and alcohol-associated HCC.

Adoptive cell therapy for solid tumors beyond CAR-T: Current challenges and emerging therapeutic advances

Adoptive cellular immunotherapy using immune cells expressing chimeric antigen receptors (CARs) is a highly specific anti-tumor immunotherapy that has shown promise in the treatment of hematological malignancies. However, there has been a slow progress toward the treatment of solid tumors owing to the complex tumor microenvironment that affects the localization and killing ability of the CAR cells. Solid tumors with a strong immunosuppressive microenvironment and complex vascular system are unaffected by CAR cell infiltration and attack. To improve their efficacy toward solid tumors, CAR cells have been modified and upgraded by "decorating" and "pruning". This review focuses on the structure and function of CARs, the immune cells that can be engineered by CARs and the transformation strategies to overcome solid tumors, with a view to broadening ideas for the better application of CAR cell therapy for the treatment of solid tumors.

Programmed Remodeling of the Tumor Milieu to Enhance NK Cell Immunotherapy Combined with Chemotherapy for Pancreatic Cancer

Natural killer (NK) cell-based adoptive immunotherapy has demonstrated encouraging therapeutic effects in clinical trials for hematological cancers. However, the effectiveness of treatment for solid tumors remains a challenge due to insufficient recruitment and infiltration of NK cells into tumor tissues. Herein, a programmed nanoremodeler (DAS@P/H/pp) is designed to remodel dense physical stromal barriers and for dysregulation of the chemokine of the tumor environment to enhance the recruitment and infiltration of NK cells in tumors. The DAS@P/H/pp is triggered by the acidic tumor environment, resulting in charge reversal and subsequent hyaluronidase (HAase) release. HAase effectively degrades the extracellular matrix, promoting the delivery of immunoregulatory molecules and chemotherapy drugs into deep tumor tissues. In mouse models of pancreatic cancer, this nanomediated strategy for the programmed remodeling of the tumor microenvironment significantly boosts the recruitment of NK92 cells and their tumor cell-killing capabilities under the supervision of multiplexed near-infrared-II fluorescence.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

CAR-NK cells for cancer immunotherapy: recent advances and future directions

Natural Killer (NK) cells, intrinsic to the innate immune system, are pivotal in combating cancer due to their independent cytotoxic capabilities in antitumor immune response. Unlike predominant treatments that target T cell immunity, the limited success of T cell immunotherapy emphasizes the urgency for innovative approaches, with a spotlight on harnessing the potential of NK cells. Despite tumors adapting mechanisms to evade NK cell-induced cytotoxicity, there is optimism surrounding Chimeric Antigen Receptor (CAR) NK cells. This comprehensive review delves into the foundational features and recent breakthroughs in comprehending the dynamics of NK cells within the tumor microenvironment. It critically evaluates the potential applications and challenges associated with emerging CAR-NK cell therapeutic strategies, positioning them as promising tools in the evolving landscape of precision medicine. As research progresses, the unique attributes of CAR-NK cells offer a new avenue for therapeutic interventions, paving the way for a more effective and precise approach to cancer treatment.