Examining the generalizability of research findings from archival data.

This initiative examined systematically the extent to which a large set of archival research findings generalizes across contexts. We repeated the key analyses for 29 original strategic management effects in the same context (direct reproduction) as well as in 52 novel time periods and geographies; 45% of the reproductions returned results matching the original reports together with 55% of tests in different spans of years and 40% of tests in novel geographies. Some original findings were associated with multiple new tests. Reproducibility was the best predictor of generalizability-for the findings that proved directly reproducible, 84% emerged in other available time periods and 57% emerged in other geographies. Overall, only limited empirical evidence emerged for context sensitivity. In a forecasting survey, independent scientists were able to anticipate which effects would find support in tests in new samples.

Advancing X-ray Luminescence for Imaging, Biosensing, and Theragnostics.

X-ray luminescence is an optical phenomenon in which chemical compounds known as scintillators can emit short-wavelength light upon the excitation of X-ray photons. Since X-rays exhibit well-recognized advantages of deep penetration toward tissues and a minimal autofluorescence background in biological samples, X-ray luminescence has been increasingly becoming a promising optical tool for tackling the challenges in the fields of imaging, biosensing, and theragnostics. In recent years, the emergence of nanocrystal scintillators have further expanded the application scenarios of X-ray luminescence, such as high-resolution X-ray imaging, autofluorescence-free detection of biomarkers, and noninvasive phototherapy in deep tissues. Meanwhile, X-ray luminescence holds great promise in breaking the depth dependency of deep-seated lesion treatment and achieving synergistic radiotherapy with phototherapy.In this Account, we provide an overview of recent advances in developing advanced X-ray luminescence for applications in imaging, biosensing, theragnostics, and optogenetics neuromodulation. We first introduce solution-processed lead halide all-inorganic perovskite nanocrystal scintillators that are able to convert X-ray photons to multicolor X-ray luminescence. We have developed a perovskite nanoscintillator-based X-ray detector for high-resolution X-ray imaging of the internal structure of electronic circuits and biological samples. We further advanced the development of flexible X-ray luminescence imaging using solution-processable lanthanide-doped nanoscintillators featuring long-lived X-ray luminescence to image three-dimensional irregularly shaped objects. We also outline the general principles of high-contrast in vivo X-ray luminescence imaging which combines nanoscintillators with functional biomolecules such as aptamers, peptides, and antibodies. High-quality X-ray luminescence nanoprobes were engineered to achieve the high-sensitivity detection of various biomarkers, which enabled the avoidance of interference from the biological matrix autofluorescence and photon scattering. By marrying X-ray luminescence probes with stimuli-responsive materials, multifunctional theragnostic nanosystems were constructed for on-demand synergistic gas radiotherapy with excellent therapeutic effects. By taking advantage of the capability of X-rays to penetrate the skull, we also demonstrated the development of controllable, wireless optogenetic neuromodulation using X-ray luminescence probes while obviating damage from traditional optical fibers. Furthermore, we discussed in detail some challenges and future development of X-ray luminescence in terms of scintillator synthesis and surface modification, mechanism studies, and their other potential applications to provide useful guidance for further advancing the development of X-ray luminescence.

A Telomerase-Activated Magnetic Resonance Imaging Probe for Consecutively Monitoring Tumor Growth Kinetics and In Situ Screening Inhibitors.

Telomerase has long been considered as a biomarker for cancer diagnosis and a therapeutic target for drug discovery. Detecting telomerase activity in vivo could provide more direct information of tumor progression and response to drug treatment, which, however, is hampered by the lack of an effective probe that can generate an output signal without a tissue penetration depth limit. In this study, using the principle of distance-dependent magnetic resonance tuning, we constructed a telomerase-activated magnetic resonance imaging probe (TAMP) by connecting superparamagnetic ferroferric oxide nanoparticles (SPFONs) and paramagnetic Gd-DOTA (Gd(III) 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid) complexes via telomerase-responsive DNA motifs. Upon telomerase-catalyzed extension of the primer in TAMP, Gd-DOTA-conjugated oligonucleotides can be liberated from the surface of SPFONs through a DNA strand displacement reaction, restoring the T1 signal of the Gd-DOTA for a direct readout of the telomerase activity. Here we show that, by tracking telomerase activity, this probe provides consistent monitoring of tumor growth kinetics during progression and in response to drug treatment and enables in situ screening of telomerase inhibitors in whole-animal models. This study provides an alternative toolkit for cancer diagnosis, treatment response assessment, and anticancer drug screening.

Reduction of anaerobic glycolysis contributes to angiotensin II-induced podocyte injury with foot process effacement.

Activation of the renin-angiotensin system is associated with podocyte injury and has been well demonstrated as a pivotal factor in the progression of chronic kidney disease. Podocyte energy metabolism is crucial for maintaining their physiological functions. However, whether renin-angiotensin system activation promotes chronic kidney disease progression by disturbing the energy metabolism of podocytes has not been elucidated. Angiotensin II, the main active molecule of the renin-angiotensin system, plays a crucial role in chronic kidney disease initiation and progression, but its impact on podocyte metabolism remains unclear. Here, we demonstrate a rapid decrease in the expression of pyruvate kinase M2, a key glycolytic enzyme, and reduced glycolytic flux in podocytes exposed to angiotensin II in vivo and in vitro. Podocyte-specific deletion of pyruvate kinase M2 in mice aggravated angiotensin II-induced glomerular and podocyte injury with foot process effacement and proteinuria. The inhibition of glycolysis was accompanied by adenosine triphosphate deficiency, cytoskeletal remodeling and podocyte apoptosis. Mechanistically, we found that angiotensin II-induced glycolysis impairment contributed to an insufficient energy supply to the foot process, leading to podocyte injury. Additionally, pyruvate kinase M2 expression was found to be reduced in podocytes from kidney biopsies of patients with hypertensive nephropathy and diabetic kidney disease. Thus, our findings suggest that glycolysis activation is a potential therapeutic strategy for podocyte injury.

Association study for the role of MMP8 gene polymorphisms in Colorectal cancer susceptibility.

BACKGROUND: Colorectal cancer (CRC) is one of the most common malignant tumors, influenced by several genetic loci in its clinical phenotypes. The aim of this study was to determine the relationship between the MMP8 gene polymorphism and CRC risk in the Chinese Han population. METHOD: This study recruited 688 CRC patients and 690 healthy controls. The relationship between MMP8 polymorphism and CRC susceptibility was assessed by calculating the odds ratio (OR) and 95% confidence interval (CI) after stratifying by age, gender, body mass index (BMI), smoking, and alcohol consumption under a multi-genetic model. RESULTS: MMP8 rs3740938 was associated with increased CRC predisposition (p = 0.016, OR = 1.24, 95% CI: 1.04-1.48), and this association was detected particularly in subjects aged > 60 years, females, people with BMI > 24 kg/m2, smokers, and drinkers. Moreover, rs3740938 was found to be associated with the pathological type of rectal cancer. CONCLUSIONS: Our results first displayed that rs3740938 in MMP8 was a risk factor for CRC predisposition. This finding may provide a new biological perspective for understanding the role of the MMP8 gene in CRC pathogenesis.

PFKFB3 downregulation aggravates Angiotensin II-induced podocyte detachment.

Podocytes play a critical role in maintaining normal glomerular filtration, and podocyte loss from the glomerular basement membrane (GBM) initiates and worsens chronic kidney disease (CKD). However, the exact mechanism underlying podocyte loss remains unclear. Fructose-2,6-biphosphatase 3 (PFKFB3) is a bifunctional enzyme that plays crucial roles in glycolysis, cell proliferation, cell survival, and cell adhesion. This study aimed to determine the role of PFKFB3 in angiotensin II (Ang II) kidney damage. We found that mice infused with Ang II developed glomerular podocyte detachment and impaired renal function accompanied by decreased PFKFB3 expression in vivo and in vitro. Inhibition of PFKFB3 with the PFKFB3 inhibitor 3PO further aggravated podocyte loss induced by Ang II. In contrast, activating PFKFB3 with the PFKFB3 agonist meclizine alleviated the podocyte loss induced by Ang II. Mechanistically, PFKFB3 knockdown likely aggravate Ang II-induced podocyte loss by suppressing talin1 phosphorylation and integrin beta1 subunit (ITGB1) activity. Conversely, PFKFB3 overexpression protected against Ang II-induced podocyte loss. These findings suggest that Ang II leads to a decrease in podocyte adhesion by suppressing PFKFB3 expression, and indicates a potential therapeutic target for podocyte injury in CKD.

Ultrasensitive Label-Free DNA Detection Based on Solution-Gated Graphene Transistors Functionalized with Carbon Quantum Dots.

Developing highly sensitive, reliable, cost-effective label-free DNA biosensors is challenging with traditional fluorescence, electrochemical, and other techniques. Most conventional methods require labeling fluorescence, enzymes, or other complex modification. Herein, we fabricate carbon quantum dot (CQD)-functionalized solution-gated graphene transistors for highly sensitive label-free DNA detection. The CQDs are immobilized on the surface of the gate electrode through mercaptoacetic acid with the thiol group. A single-stranded DNA (ssDNA) probe is immobilized on CQDs by strong π-π interactions. The ssDNA probe can hybridize with the ssDNA target and form double-stranded DNA, which led to a shift of Dirac voltage and the channel current response. The limit of detection can reach 1 aM which is 2-5 orders of magnitude lower than those of other methods reported previously. The sensor also exhibits a good linear range from 1 aM to 0.1 nM and has good specificity. It can effectively distinguish one-base mismatched target DNA. The response time is about 326 s for the 1 aM target DNA molecules. This work provides good perspectives on the applications in biosensors.

Roles of SIRT6 in kidney disease: a novel therapeutic target.

SIRT6 is an NAD+ dependent deacetylase that belongs to the mammalian sirtuin family. SIRT6 is mainly located in the nucleus and regulates chromatin remodeling, genome stability, and gene transcription. SIRT6 extensively participates in various physiological activities such as DNA repair, energy metabolism, oxidative stress, inflammation, and fibrosis. In recent years, the role of epigenetics such as acetylation modification in renal disease has gradually received widespread attention. SIRT6 reduces oxidative stress, inflammation, and renal fibrosis, which is of great importance in maintaining cellular homeostasis and delaying the chronic progression of kidney disease. Here, we review the structure and biological function of SIRT6 and summarize the regulatory mechanisms of SIRT6 in kidney disease. Moreover, the role of SIRT6 as a potential therapeutic target for the progression of kidney disease will be discussed. SIRT6 plays an important role in kidney disease. SIRT6 regulates mitochondrial dynamics and mitochondrial biogenesis, induces G2/M cycle arrest, and plays an antioxidant role in nephrotoxicity, IR, obstructive nephropathy, and sepsis-induced AKI. SIRT6 prevents and delays progressive CKD induced by hyperglycemia, kidney senescence, hypertension, and lipid accumulation by regulating mitochondrial biogenesis, and has antioxidant, anti-inflammatory, and antifibrosis effects. Additionally, hypoxia, inflammation, and fibrosis are the main mechanisms of the AKI-to-CKD transition. SIRT6 plays a critical role in the AKI-to-CKD transition and kidney repair through anti-inflammatory, antifibrotic, and mitochondrial quality control mechanisms. AKI Acute kidney injury, CKD Chronic kidney disease.

Roles of Mitochondrial DNA Damage in Kidney Diseases: A New Biomarker.

The kidney is a mitochondria-rich organ, and kidney diseases are recognized as mitochondria-related pathologies. Intact mitochondrial DNA (mtDNA) maintains normal mitochondrial function. Mitochondrial dysfunction caused by mtDNA damage, including impaired mtDNA replication, mtDNA mutation, mtDNA leakage, and mtDNA methylation, is involved in the progression of kidney diseases. Herein, we review the roles of mtDNA damage in different setting of kidney diseases, including acute kidney injury (AKI) and chronic kidney disease (CKD). In a variety of kidney diseases, mtDNA damage is closely associated with loss of kidney function. The level of mtDNA in peripheral serum and urine also reflects the status of kidney injury. Alleviating mtDNA damage can promote the recovery of mitochondrial function by exogenous drug treatment and thus reduce kidney injury. In short, we conclude that mtDNA damage may serve as a novel biomarker for assessing kidney injury in different causes of renal dysfunction, which provides a new theoretical basis for mtDNA-targeted intervention as a therapeutic option for kidney diseases.

Cytosolic Delivery of Thiolated Mn-cGAMP Nanovaccine to Enhance the Antitumor Immune Responses.

As a stimulator of interferon gene (STING), cyclic dinucleotide activates a broad cellular immune response for anti-cancer immunotherapy (CIT). However, the inherent of instability of 2' 3'-cyclic-GMP-AMP (cGAMP) with poor cellular targeting, rapid clearance, and inefficient transport to the cytoplasm seriously hinders cGAMP potency. Here, a thiolated and Mn2+ coordinated cyclic dinucleotide nanovaccine (termed as Mn-cGAMP NVs) to enable direct cytosolic co-delivery of cGAMP and Mn2+ to potentiate the antitumor immune response is presented. In the NVs, the fixation cGAMP with Mn2+ ions not only improve its stability, but also potentiate the activation of STING. Meanwhile, the presence of polysulfides on the NVs surface allowed direct cytosolic delivery while avoiding degradation. In this way, the production of cytokines for activating T cells immunity is greatly elevated, which in turn suppressed the primary and distal tumors growth through long-term immune memory and led to long-term survival of poorly immunogenic B16F10 melanoma mice. Moreover, by further combining with anti-PD-L1 monoclonal antibody, synergistic T cells antitumor immune response is elicited. This work offers a promising strategy to enhance the potency of cGAMP, holding a considerable potential for CIT applications.

Local and Targeted Delivery of Immune Checkpoint Blockade Therapeutics.

Immune checkpoint blockade (ICB) therapy elicits antitumor response by inhibiting immune suppressor components, including programmed cell death protein 1 and its ligand (PD-1/PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4). Despite improved therapeutic efficacy, the clinical response rate is still unsatisfactory as revealed by the fact that only a minority of patients experience durable benefits. Additionally, "off-target" effects after systemic administration remain challenging for ICB treatment. To this end, the local and targeted delivery of ICB agents instead could be a potential solution to maximize the therapeutic outcomes while minimizing the side effects.In this Account, our recent studies directed at the development of different strategies for the local and targeted delivery of ICB agents are discussed. For example, transdermal microneedle patches loaded with anti-programmed death-1 antibody (aPD1) and anti-CTLA4 were developed to facilitate sustained release of ICB agents at the diseased sites. Triggered release could also be achieved by various stimuli within the tumor microenvironment, including low pH and abnormally expressed enzymes. Recently, the combination of an anti-programmed death-ligand 1 antibody (aPD-L1) loaded hollow-structured microneedle patch with cold atmospheric plasma (CAP) therapy was also reported. Microneedles provided microchannels to facilitate the transdermal transport of CAP and further induce immunogenic tumor cell death, which could be synergized by the local release of aPD-L1. In addition, in situ formed injectable or sprayable hydrogels were tailored to deliver immunomodulatory antibodies to the surgical bed to inhibit tumor recurrence after primary tumor resection. In paralell, inspired by the unique targeting ability of platelets toward the inflammatory sites, we engineered natural platelets decorated with aPD-L1 for targeted delivery after tumor resection to inhibit tumor recurrence. We further constructed a cell-cell combination delivery platform based on conjugates of platelets and hematopoietic stem cells (HSCs) for leukemia treatment. With the homing ability of HSCs to the bone marrow, the HSC-platelet-aPD1 assembly could effectively deliver aPD1 in an acute myeloid leukemia mouse model. Besides living cells, we also leveraged HEK293T-derived vesicles with PD1 receptors on their surfaces to disrupt the PD-1/PD-L1 immune inhibitory pathway. Moreover, the inner space of the vesicles allowed the packaging of an indoleamine 2,3-dioxygenase inhibitor, further reinforcing the therapeutic efficacy. A similar approach has also been demonstrated by genetically engineering platelets overexpressing PD1 receptor for postsurgical treatment. We hope the local and targeted ICB agent delivery methods introduced in this collection would further inspire the development of advanced drug delivery strategies to improve the efficiency of cancer treatment while alleviating side effects.

Roadmap on nanomedicine.

Since the launch of the Alliance for Nanotechnology in Cancer by the National Cancer Institute in late 2004, several similar initiatives have been promoted all over the globe with the intention of advancing the diagnosis, treatment and prevention of cancer in the wake of nanoscience and nanotechnology. All this has encouraged scientists with diverse backgrounds to team up with one another, learn from each other, and generate new knowledge at the interface between engineering, physics, chemistry and biomedical sciences. Importantly, this new knowledge has been wisely channeled towards the development of novel diagnostic, imaging and therapeutic nanosystems, many of which are currently at different stages of clinical development. This roadmap collects eight brief articles elaborating on the interaction of nanomedicines with human biology; the biomedical and clinical applications of nanomedicines; and the importance of patient stratification in the development of future nanomedicines. The first article reports on the role of geometry and mechanical properties in nanomedicine rational design; the second articulates on the interaction of nanomedicines with cells of the immune system; and the third deals with exploiting endogenous molecules, such as albumin, to carry therapeutic agents. The second group of articles highlights the successful application of nanomedicines in the treatment of cancer with the optimal delivery of nucleic acids, diabetes with the sustained and controlled release of insulin, stroke by using thrombolytic particles, and atherosclerosis with the development of targeted nanoparticles. Finally, the last contribution comments on how nanomedicine and theranostics could play a pivotal role in the development of personalized medicines. As this roadmap cannot cover the massive extent of development of nanomedicine over the past 15 years, only a few major achievements are highlighted as the field progressively matures from the initial hype to the consolidation phase.

Gaseous Plastron on Natural and Biomimetic Surfaces for Resisting Marine Biofouling.

In recent years, various biomimetic materials capable of forming gaseous plastron on their surfaces have been fabricated and widely used in various disciplines and fields. In particular, on submerged surfaces, gaseous plastron has been widely studied for antifouling applications due to its ecological and economic advantages. Gaseous plastron can be formed on the surfaces of various natural living things, including plants, insects, and animals. Gaseous plastron has shown inherent anti-biofouling properties, which has inspired the development of novel theories and strategies toward resisting biofouling formation on different surfaces. In this review, we focused on the research progress of gaseous plastron and its antifouling applications.

Photogenerated Holes Mediated Nitric Oxide Production for Hypoxic Tumor Treatment.

Nitric oxide (NO) is a gaseous signal molecule with multiple physiological functions, and it also plays a key role in cancer therapy. However, the production of NO which depends on O2 or H2 O2 is limited within the tumor microenvironment, leading to unsatisfactory anticancer effect. Herein, we report a NO-based phototherapeutic strategy mediated by photogenerated holes for hypoxic tumors, which is achieved by irradiation of the poly-L-arginine modified carbon-dots-doped graphitic carbon nitride nanomaterial (ArgCCN). Upon red light irradiation, the photogenerated holes on ArgCCN oxidized water into H2 O2 which subsequently oxidized the arginine residues to produce NO. In vitro and in vivo experiments showed that the high concentration of NO produced by ArgCCN could induce cancer cell apoptosis. The presented phototherapeutic strategy is based on microenvironment-independent photogenerated holes mediated oxidation reaction, paving the way for the development of NO therapeutic strategy.

AKAP1 mediates high glucose-induced mitochondrial fission through the phosphorylation of Drp1 in podocytes.

Increasing evidence suggests that mitochondrial dysfunction plays a critical role in the development of diabetic kidney disease (DKD), however, its specific pathomechanism remains unclear. A-kinase anchoring protein (AKAP) 1 is a scaffold protein in the AKAP family that is involved in mitochondrial fission and fusion. Here, we show that rats with streptozotocin (STZ)-induced diabetes developed podocyte damage accompanied by AKAP1 overexpression and that AKAP1 closely interacted with the mitochondrial fission enzyme dynamin-related protein 1 (Drp1). At the molecular level, high glucose (HG) promoted podocyte injury and Drp1 phosphorylation at Ser637 as proven by decreased mitochondrial membrane potential, elevated reactive oxygen species generation, reduced adenosine triphosphate synthesis, and increased podocyte apoptosis. Furthermore, the AKAP1 knockdown protected HG-induced podocyte injury and suppressed HG-induced Drp1 phosphorylation at Ser637. AKAP1 overexpression aggravated HG-induced mitochondrial fragmentation and podocyte apoptosis. The coimmunoprecipitation assay showed that HG-induced Drp1 interacted with AKAP1, revealing that AKAP1 could recruit Drp1 from the cytoplasm under HG stimulation. Subsequently, we detected the effect of drp1 phosphorylation on Ser637 by transferring several different Drp1 mutants. We demonstrated that activated AKAP1 promoted Drp1 phosphorylation at Ser637, which promoted the transposition of Drp1 to the surface of the mitochondria and accounts for mitochondrial dysfunction events. These findings indicate that AKAP1 is the main pathogenic factor in the development and progression of HG-induced podocyte injury through the destruction of mitochondrial dynamic homeostasis by regulating Drp1 phosphorylation in human podocytes.

Bioinspired and Biomimetic Nanomedicines.

Nanomedicine development aims to enhance the efficacy, accuracy, safety, and/or compliance of diagnosis and treatment of diseases by leveraging the unique properties of engineered nanomaterials. To this end, a multitude of organic and inorganic nanoparticles have been designed to facilitate drug delivery, sensing, and imaging, some of which are currently in clinical trials or have been approved by the Food and Drug Administration (FDA). In the process, the increasing knowledge in understanding how natural particulates, including cells, pathogens, and organelles, interact with body and cellular systems has spurred efforts to mimic their morphology and functions for developing new generations of nanomedicine formulations. In addition, the advances in bioengineering tools, bioconjugation chemistries, and bio-nanotechnologies have further enabled researchers to exploit these natural particulates for theranostic purposes. In this Account, we will discuss the recent progress in our lab on engineering bioinspired and biomimetic synthetic and cellular systems toward rational design of nanomedicine platforms for treating diabetes and cancer. Inspired by the structure and response mechanism of pancreatic ß-cells, we synthesized a series of insulin granule-like vesicles that can respond to high blood or intestinal glucose levels for aiding in transdermal or oral insulin delivery, respectively. Then, to more closely mimic the multicompartmental architecture of ß-cells, we further developed synthetic artificial cells with vesicle-in-vesicle superstructures which can sense blood glucose levels and dynamically release insulin via a membrane fusion process. Meanwhile, clues drawn from the traits of anaerobic bacteria that selectively invade and proliferate in solid tumors inspired the synthesis of a light-tuned hypoxia-responsive nanovesicle for implementing synergistic cancer therapy. In parallel, we also studied how autologous particulates could be recruited for developing advanced drug delivery systems. Through combination of genetic engineering and top-down cell engineering technologies, biomimetic nanomedicines derived from cytoplasmic membrane with programmed death 1 (PD-1) receptors expressed on surfaces were generated and employed for cancer immunotherapy. Based on our earlier study where aPD-L1 (antibodies against PD ligand 1)-conjugated platelets could release aPD-L1-bearing particles in situ and inhibit postsurgical tumor recurrence, we further genetically engineered megakaryocytes, the precursor cells of platelets, to express PD-1 receptors. In this way, platelets born with checkpoint blocking activity could be produced directly in vitro, avoiding post chemical modification processes while exerting similar therapeutic impact. As a further extension, by virtue of the bone marrow-homing ability of hematopoietic stem cells (HSCs), we recently conceived a cell-combination strategy by conjugating HSCs with platelets decorated with antibodies against PD1 (aPD-1) to suppress the growth and recurrence of leukemia. While we are still on the way of digging deep to understand and optimize bioinspired and biomimetic drug carriers, we expect that the strategies summarized in this Account would contribute to the development of advanced nanomedicines.

Synthetic beta cells for fusion-mediated dynamic insulin secretion.

Generating artificial pancreatic beta cells by using synthetic materials to mimic glucose-responsive insulin secretion in a robust manner holds promise for improving clinical outcomes in people with diabetes. Here, we describe the construction of artificial beta cells (AßCs) with a multicompartmental 'vesicles-in-vesicle' superstructure equipped with a glucose-metabolism system and membrane-fusion machinery. Through a sequential cascade of glucose uptake, enzymatic oxidation and proton efflux, the AßCs can effectively distinguish between high and normal glucose levels. Under hyperglycemic conditions, high glucose uptake and oxidation generate a low pH (<5.6), which then induces steric deshielding of peptides tethered to the insulin-loaded inner small liposomal vesicles. The peptides on the small vesicles then form coiled coils with the complementary peptides anchored on the inner surfaces of large vesicles, thus bringing the membranes of the inner and outer vesicles together and triggering their fusion and insulin 'exocytosis'.

KO of 5-InsP7 kinase activity transforms the HCT116 colon cancer cell line into a hypermetabolic, growth-inhibited phenotype.

The inositol pyrophosphates 5-InsP7 (diphosphoinositol pentakisphosphate) and 1,5-InsP8 (bis-diphosphoinositol tetrakisphosphate) are highly energetic cellular signals interconverted by the diphosphoinositol pentakisphosphate kinases (PPIP5Ks). Here, we used CRISPR to KO PPIP5Ks in the HCT116 colon cancer cell line. This procedure eliminates 1,5-InsP8 and raises 5-InsP7 levels threefold. Expression of p53 and p21 was up-regulated; proliferation and G1/S cell-cycle transition slowed. Thus, PPIP5Ks are potential targets for tumor therapy. Deletion of the PPIP5Ks elevated [ATP] by 35%; both [ATP] and [5-InsP7] were restored to WT levels by overexpression of PPIP5K1, and a kinase-compromised PPIP5K1 mutant had no effect. This covariance of [ATP] with [5-InsP7] provides direct support for an energy-sensing attribute (i.e., 1 mM Km for ATP) of the 5-InsP7-generating inositol hexakisphosphate kinases (IP6Ks). We consolidate this conclusion by showing that 5-InsP7 levels are elevated on direct delivery of ATP into HCT116 cells using liposomes. Elevated [ATP] in PPIP5K-/- HCT116 cells is underpinned by increased mitochondrial oxidative phosphorylation and enhanced glycolysis. To distinguish between 1,5-InsP8 and 5-InsP7 as drivers of the hypermetabolic and p53-elevated phenotypes, we used IP6K2 RNAi and the pan-IP6K inhibitor, N2-(m-trifluorobenzyl), N6-(p-nitrobenzyl) purine (TNP), to return 5-InsP7 levels in PPIP5K-/- cells to those of WT cells without rescuing 1,5-InsP8 levels. Attenuation of IP6K restored p53 expression but did not affect the hypermetabolic phenotype. Thus, we conclude that 5-InsP7 regulates p53 expression, whereas 1,5-InsP8 regulates ATP levels. These findings attribute hitherto unsuspected functionality for 1,5-InsP8 to bioenergetic homeostasis.

Small GTPase Arf6 regulates diabetes-induced cholesterol accumulation in podocytes.

Podocyte injury is a critical factor for the initiation and progression of diabetic kidney disease (DKD). However, the underlying mechanisms of podocyte injury in DKD have not been completely elucidated. Studies suggested that intracellular cholesterol accumulation was correlated with podocyte injury, but the cause of podocyte cholesterol disorders in DKD are still unknown. ADP-ribosylation factor 6 (Arf6) is a small GTPase with pleiotropic effects and has previously been shown to regulate ATP-binding cassette transporter 1 (ABCA1) recycling, and thus, cholesterol homeostasis. However, Arf6 involvement in cholesterol metabolism in podocytes is scarce. To investigate the role of Arf6 in cholesterol modulation in podocytes, the effect of Arf6 on the regulation of the cholesterol transporter ABCA1 was studied in podocytes in vivo and in vitro. Intracellular cholesterol accumulation was significantly increased in podocytes from streptozotocin-induced diabetic rats and that hyperglycemia downregulated the expression of Arf6. Arf6 knockdown could cause ABCA1 recycling disorders, and thus, further aggravate cholesterol accumulation in podocytes under high-glucose (HG) conditions. Our results demonstrate that HG-induced cholesterol accumulation and cellular injury in podocytes may be related to the recycling disorder of ABCA1 caused by the downexpression of Arf6 in DKD.

Semi-artificial Photosynthetic CO2 Reduction through Purple Membrane Re-engineering with Semiconductor.

The engineering of biological pathways with man-made materials provides inspiring blueprints for sustainable fuel production. Here, we leverage a top-down cellular engineering strategy to develop a new semi-artificial photosynthetic paradigm for carbon dioxide reduction via enveloping Halobacterium purple membrane-derived vesicles over Pd-deposited hollow porous TiO2 nanoparticles. In this biohybrid, the membrane protein, bacteriorhodopsin, not only retains its native biological function of pumping protons but also acts as a photosensitizer that injects light-excited electrons into the conduction band of TiO2. As such, the electrons trapped on Pd cocatalysts and the protons accumulated inside the cytomimetic architecture act in concert to reduce CO2 via proton-coupled multielectron transfer processes. This study provides an alternative toolkit for developing robust semi-artificial photosynthetic systems for solar energy conversion.