Nuclear Targets Research Articles

Hepatic deletion of serine palmitoyl transferase 2 impairs ceramide/sphingomyelin balance, bile acids homeostasis and leads to liver damage in mice

Ceramides (Cer) have been shown as lipotoxic inducers, which disturb numerous cell-signaling pathways, leading to metabolic disorders such as type 2 diabetes. In this study, we aimed to determine the role of de novo hepatic ceramide synthesis in energy and liver homeostasis in mice. We generated mice lacking serine palmitoyltransferase 2 (Sptlc2), the rate limiting enzyme of ceramide de novo synthesis, in liver under albumin promoter. Liver function, glucose homeostasis, bile acid (BA) metabolism and hepatic sphingolipids content were assessed using metabolic tests and LC-MS. Despite lower expression of hepatic Sptlc2, we observed an increased concentration of hepatic Cer, associated with a 10-fold increase in neutral sphingomyelinase 2 (nSMase2) expression, and a decreased sphingomyelin content in the liver. Sptlc2ΔLiv mice were protected against obesity induced by high fat diet and displayed a defect in lipid absorption. In addition, an important increase in tauro-muricholic acid was associated with a downregulation of the nuclear BA receptor FXR target genes. Sptlc2 deficiency also enhanced glucose tolerance and attenuated hepatic glucose production, while the latter effect was dampened in presence of nSMase2 inhibitor. Finally, Sptlc2 disruption promoted apoptosis, inflammation and progressive development of hepatic fibrosis, worsening with age. Our data suggest a compensatory mechanism to regulate hepatic ceramides content from sphingomyelin hydrolysis, with deleterious impact on liver homeostasis. In addition, our results show the involvement of hepatic sphingolipid modulation in BA metabolism and hepatic glucose production in an insulin-independent manner, which highlight the still under-researched role of ceramides in many metabolic functions.

Contribution of nuclear excitation electromagnetic form factors in C12 and O16 to the Coulomb sum rule

We report on empirical parameterizations of longitudinal and transverse nuclear excitation electromagnetic form factors in ${\rm ^{12}C}$ and ${\rm ^{16}O}$. We extract the contribution of nuclear excitations to the Normalized Inelastic Coulomb Sum Rule (\csr) as a function of momentum transfer $\bf q$ and find that it is significant (0.29$\pm$0.030 at $\bf q$= 0.22 GeV). The total contributions of nuclear excitations to $S_L({\bf q})$ in ${\rm ^{12}C}$ and ${\rm ^{16}O}$ are found to be equal within the uncertainties. Since the cross sections for nuclear excitations are significant, the radiative tails from nuclear excitations should be included in precise calculations of radiative corrections to quasielastic electron scattering at low $\bf q$ and deep-inelastic electron scattering at large energy transfers $\nu$. The parameterizations also serve as a benchmark in testing theoretical modeling of cross sections for excitation of nuclear states in electron and neutrino interactions on nuclear targets at low energies.

Connexin 37 sequestering of activated-ERK in the cytoplasm promotes p27-mediated endothelial cell cycle arrest.

Connexin37-mediated regulation of cell cycle modulators and, consequently, growth arrest lack mechanistic understanding. We previously showed that arterial shear stress up-regulates Cx37 in endothelial cells and activates a Notch/Cx37/p27 signaling axis to promote G1 cell cycle arrest, and this is required to enable arterial gene expression. However, how induced expression of a gap junction protein, Cx37, up-regulates cyclin-dependent kinase inhibitor p27 to enable endothelial growth suppression and arterial specification is unclear. Herein, we fill this knowledge gap by expressing wild-type and regulatory domain mutants of Cx37 in cultured endothelial cells expressing the Fucci cell cycle reporter. We determined that both the channel-forming and cytoplasmic tail domains of Cx37 are required for p27 up-regulation and late G1 arrest. Mechanistically, the cytoplasmic tail domain of Cx37 interacts with, and sequesters, activated ERK in the cytoplasm. This then stabilizes pERK nuclear target Foxo3a, which up-regulates p27 transcription. Consistent with previous studies, we found this Cx37/pERK/Foxo3a/p27 signaling axis functions downstream of arterial shear stress to promote endothelial late G1 state and enable up-regulation of arterial genes.

EFT analysis of New Physics at COHERENT

Using an effective field theory approach, we study coherent neutrino scattering on nuclei, in the setup pertinent to the COHERENT experiment. We include non-standard effects both in neutrino production and detection, with an arbitrary flavor structure, with all leading Wilson coefficients simultaneously present, and without assuming factorization in flux times cross section. A concise description of the COHERENT event rate is obtained by introducing three generalized weak charges, which can be associated (in a certain sense) to the production and scattering of νe, νμ and {overline{nu}}_{mu } on the nuclear target. Our results are presented in a convenient form that can be trivially applied to specific New Physics scenarios. In particular, we find that existing COHERENT measurements provide percent level constraints on two combinations of Wilson coefficients. These constraints have a visible impact on the global SMEFT fit, even in the constrained flavor-blind setup. The improvement, which affects certain 4-fermion LLQQ operators, is significantly more important in a flavor-general SMEFT. Our work shows that COHERENT data should be included in electroweak precision studies from now on.

HAPSTR1 localizes HUWE1 to the nucleus to limit stress signaling pathways

HUWE1 is a large, enigmatic HECT-domain ubiquitin ligase implicated in the regulation of diverse pathways, including DNA repair, apoptosis, and differentiation. How HUWE1 engages its structurally diverse substrates and how HUWE1 activity is regulated are unknown. Using unbiased quantitative proteomics, we find that HUWE1 targets substrates in a largely cell-type-specific manner. However, we identify C16orf72/HAPSTR1 as a robust HUWE1 substrate in multiple cell lines. Previously established physical and genetic interactions between HUWE1 and HAPSTR1 suggest that HAPSTR1 positively regulates HUWE1 function. Here, we show that HAPSTR1 is required for HUWE1 nuclear localization and nuclear substrate targeting. Nuclear HUWE1 is required for both cell proliferation and modulation of stress signaling pathways, including p53 and nuclear factor κB (NF-κB)-mediated signaling. Combined, our results define a role for HAPSTR1 in gating critical nuclear HUWE1 functions.

A comparison of freezer-stored DNA and herbarium tissue samples for chloroplast assembly and genome skimming.

The use of DNA from herbarium specimens is an increasingly important source for evolutionary studies in plant biology, particularly in cases where species are rare or difficult to obtain. Here we compare the utility of DNA from herbarium tissues to their freezer-stored DNA counterparts via the Hawaiian Plant DNA Library. Plants collected for the Hawaiian Plant DNA Library were simultaneously accessioned as herbarium specimens at the time of collection, from 1994-2019. Paired samples were sequenced using short-read sequencing and assessed for chloroplast assembly and nuclear gene recovery. Herbarium specimen-derived DNA was statistically more fragmented than freezer-stored DNA derived from fresh tissue, leading to poorer chloroplast assembly and overall lower coverage. The number of nuclear targets recovered varied mostly by total sequencing reads per library and age of specimen, but not by storage method (herbarium or long-term freezer). Although there was evidence of DNA damage in the samples, there was no evidence that it was related to the length of time in storage, whether frozen or as herbarium specimens. DNA extracted from herbarium tissues will continue to be invaluable, despite being highly fragmented and degraded. Rare floras would benefit from both traditional herbarium storage methods and extracted DNA freezer banks.

START domain-mediated nuclear translocation of Them1 regulates the expression of metabolic genes relative to thermogenesis in brown adipocytes

Thioesterase superfamily member 1 (Them1) is a long-chain fatty acyl-CoA thioesterase that is highly expressed in brown adipose tissue (BAT), where it limits energy expenditure. Them1 is comprised of tandem enzymatic domains and a C-terminal lipid-binding steroidogenic acute regulatory protein (StAR)-related lipid transfer (START) domain. Fatty acid binding to the START domain stabilizes the enzymatic domains and increases activity, whereas lysophosphatidylcholine (LPC) acts in the opposite manner. In brown adipocytes, Them1 localizes to puncta within the cytoplasm, but diffuses in response to β-adrenergic stimulation after which it is also found in the nucleus. The aim of this study was to determine the mechanism of Them1 nuclear trafficking and the metabolic consequences. METHODS: Identification of a putative nuclear localization signal (NLS) was determined by computational analysis. Full-length, NLS-deleted, or truncated Them1 cDNA constructs were cloned and linked to EGFP. Plasmid or adenoviral vectors were transfected into immortalized brown adipose cells (iBAs) that do not express Them1. Them1 was visualized by live cell confocal imaging via EGFP and with NucSpot nuclear staining. Signal quantification was performed with Imaris software. Them1 nuclear localization was evaluated in the presence or absence of norepinephrine (NE), leptomycin B, cycloheximide, or lipids that bind the START domain. Them1 nuclear localization was also quantified in BAT from mice treated with a β3-adrenergic receptor agonist, CL316,243. mRNA expression in iBAs expressing full-length or NLS-mutant Them1 in response to NE was determined by RNA-Seq. RESULTS: In the diffuse state, Them1 localized to the nucleus in a time-dependent manner. The NLS resides in a hinge region between the thioesterase domains and the START domain. Deletion of either the NLS or the START domain blocked nuclear targeting. Conversely, truncated Them1 containing only the START domain was targeted to the nucleus. Entry into the nucleus was balanced by trafficking out of the nucleus and new protein synthesis was not required, as evidenced by using leptomycin B to block nuclear efflux and cycloheximide to block protein synthesis, respectively. Incubation of NE-stimulated iBAs with LPC promoted nuclear Them1 translocation. Them1 protein was also detected in the nucleus of BAT from wild-type mice in response to CL administration. Nuclear Them1 localization in iBAs was associated with down-regulated mRNA expression of genes that control lipid and glucose metabolism during cold adaptation. CONCLUSIONS: Our data suggest that LPC generated during thermogenesis binds and destabilizes the START domain, leading to exposure of the NLS and nuclear trafficking of Them1 in response to β-adrenergic stimulation. Once inside the nucleus, Them1 regulates the transcription of lipid and glucose metabolic enzymes that are required for chronic cold adaptation. This work was supported by NIH DK103046 to DEC, SJH, and EAO This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Enhance Mitochondrial Damage by Nuclear Export Inhibition to Suppress Tumor Growth and Metastasis with Increased Antitumor Properties of Macrophages.

Mitochondria-targeting damage has become a popular therapeutic option for tumor metastasis; however, its efficacy is limited by the adaptive rescue capacity of nuclei. There is an urgent need for a dual mitochondrial and nuclear targeting strategy that can also increase the antitumor capacity of macrophages. In this study, XPO1 inhibitor KPT-330 nanoparticles were combined with mitochondria-targeting lonidamine (TPP-LND) nanoparticles. The combination of nanoparticles with a 1:4 ratio of KPT and TL demonstrated the best synergistic effect in restraining the proliferation and metastasis of 4T1 breast cancer cells. Investigating the mechanisms both in vitro and in vivo, it was found that KPT nanoparticles not only directly impede tumor growth and metastasis by controlling the expression of associated proteins but also indirectly facilitate mitochondrial damage. The two nanoparticles synergistically decreased the expression of cytoprotective factors, such as Mcl-1 and Survivin, causing mitochondrial dysfunction and thus inducing apoptosis. Additionally, it downregulated metastasis-related proteins like HIF-1α, vascular endothelial growth factor (VEGF), and matrix metalloproteinase 2 (MMP-2) and reduced endothelial-to-mesenchymal transition. Significantly, their combination increased the ratio of M1 tumor-associated macrophages (TAMs)/M2 TAMs both in vitro and in vivo and increased the phagocytosis of tumor cells by macrophages, thus suppressing tumor growth and metastasis. In summary, this research revealed that nuclear export inhibition can synergistically enhance the prevention of mitochondrial damage to tumor cells, heightening the antitumor properties of TAMs, thereby providing a viable and safe therapeutic approach for the treatment of tumor metastasis.

Upgrading the Bomb: Why and How the US Provides Advanced Nuclear Assistance to Junior Allies

Abstract Why and how does the US provide advanced nuclear assistance to junior nuclear allies? Existing nuclear literature downplays the possibility that the US strategically employs the technical assistance option as a post-proliferation toolkit to control allied nuclear proliferation. Addressing the first question—why—I argue that the US provides advanced nuclear assistance to junior allies to inhibit the latter’s growing tendency towards unilateralism after nuclear acquisition, meanwhile inducing greater allied nuclear coordination. By forging advanced nuclear partnerships, the US seeks simultaneously to draw junior allies closer to the American nuclear leadership and establish coordinated nuclear strike plans and joint nuclear targeting. Addressing the second question—how—I claim that the US provides advanced nuclear assistance at a protracted pace and in a restricted manner, calculated to exert influence over recipient junior allies for as long as possible. To provide the plausibility probe of my argument, I explore two historical cases: The US’s strategic advanced nuclear assistance to the UK and to France. I conclude by identifying avenues for future study and the policy implications for China’s potential response to North Korea’s nuclear sophistication.

Abstract LB016: Immunotherapeutic potential of ST316, a peptide antagonist of β-catenin

Abstract The transcription factor β-catenin is a key player in many cellular processes, including stem cell renewal, cellular homeostasis and inflammation. Deregulation of β-catenin occurs frequently in several cancer types by mutation or overexpression of the β-catenin gene or mutation of negative regulators such as Adenomatous Polyposis Coli (APC). ST316 is a novel peptide antagonist that specifically interferes with the association of β-catenin with its co-activator BCL9, disrupting β-catenin nuclear localization and attenuating target gene expression. In an orthotopic triple-negative breast cancer (TNBC) model, ST316 demonstrates potent anti-tumor activity, resulting in 84% tumor growth inhibition (TGI) (p<0.001 vs. vehicle control). In addition to its cell-autonomous mechanisms, deregulated Wnt/β-catenin signaling can promote tumorigenesis by impacting the tumor microenvironment. Reprogramming of immunosuppressive M2-like Tumor Associated Macrophages (TAMs) toward an immune-promoting program (M1-like) is an attractive cancer immunotherapeutic strategy. Here we explored ST316 potential for macrophage repolarization toward the M1-like phenotype, activation of cytotoxic T-cells in macrophage/T-cell co-culture assays and cooperation of ST316 with anti-PD-1 to enhance anti-tumor activity in vivo. Initial studies demonstrate that human macrophages derived from Peripheral Blood Mononuclear Cells (hPBMCs) and subsequently committed to the M2-like identity are reprogrammed toward an M1-like phenotype upon ST316 exposure. ST316 treatment dose-dependently suppressed expression of the M2 marker CD163 by flow cytometry and quantitative PCR, resulting in 100-fold increase in the M1/M2 ratio without substantial impact on cell viability. Importantly, T-cell viability and activation markers associated with M1-state (CD80, CD86) were not affected by ST316 at the concentrations used in these studies. Further, in co-cultures of M2 macrophage with T cells, ST316 exposure resulted in a three-fold increase in T-cell activation compared to control M2/T cell co-cultures, as measured by intracellular IFN-γ staining. Finally, in an orthotopic TNBC model in vivo, subtherapeutic ST316 enhanced the anti-tumor activity of anti-PD-1 [85% TGI with combination, compared to 51% TGI with anti-PD1 alone (p<0.01) and -9% TGI with subtherapeutic ST316 alone (p<0.001)]. Anti-tumor activity was accompanied by an increase the M1/M2 ratio. Overall, these results support the immuno-therapeutic potential of ST316 and extend the application range of ST316 to include Wnt-driven cancers with poor clinical response to immune checkpoint blockade and other immunotherapeutic agents. Citation Format: Claudio Scuoppo, Lila Ghamsari, Erin Gallagher, Siok Leong, Mark Koester, Rick Ramirez, Jerel Gonzales, Gene Merutka, Barry Kappel, Abi Vainstein-Haras, Jim Rotolo. Immunotherapeutic potential of ST316, a peptide antagonist of β-catenin [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB016.

Erratum for the Research Article "Nuclear receptor PXR targets AKR1B7 to protect mitochondrial metabolism and renal function in AKI" by X. Yu et al.

Erratum for the Research Article "Nuclear receptor PXR targets AKR1B7 to protect mitochondrial metabolism and renal function in AKI" by X. Yu et al.

Abstract 1614: Antitumor activity of novel and potent YAP/TAZ-TEAD inhibitorstargeting the Hippo pathway in solid tumors

Abstract The Hippo pathway is evolutionarily conserved and known to regulate diverse cellular processes, including cell survival, proliferation, differentiation, migration, and organ size. The key regulator of Hippo pathway is transcriptional enhanced associate domain (TEAD) transcription factors, which directly bind with YAP/TAZ and then drive the multiple signaling by activating target gene expression on nuclear. Loss-of-function mutations in the upstream activators, NF2-LATS1/2-MST1/2, trigger YAP/TAZ nuclear translocation and target gene transcription (Hippo-off state). This YAP/TAZ-TEAD complex is overexpressed and leads to metastatic progression in various cancers including malignant mesothelioma, NSCLC, ovarian cancer or cholangiocarcinoma. A recent development in targeting the Hippo pathway has been focused on the discovery of a central lipophilic pocket in TEAD amenable to the small-molecule binding site of autopalmitoylation. Within this lipophilic palmitate pocket, post-translational S-palmitoylation of TEAD at a conserved catalytic cysteine (Cys) residue (e.g., C380) leads to TEAD stabilization and is believed to be critical for maintaining appropriate protein folding to enable the formation of the transcriptionally active YAP/TAZ -TEAD complex. Therefore, targeting the palmitate pocket with allosteric small molecules inhibitor disrupt the formation of the YAP/TAZ-TEAD complex and modulate YAP/TAZ-TEAD driven gene transcription. We have identified a series of novel, potent small-molecule inhibitors of the YAP/TAZ-TEAD transcriptional complex. It showed under 20 nM of potency in the inhibition of TEAD luciferase reporter assay in MCF7-TEAD-luc cells. These TEAD inhibitors inhibited YAP/TAZ-TEAD protein-protein interaction in H226 cells harboring neurofibromin 2 (NF2) alteration. In addition, our lead compounds exhibited dose-dependent growth inhibitory effects in Hippo pathway-altered cancer cell lines and reduced the YAP/TAZ-TEAD target gene expression, CTGF, and CYR61 in H226 cells. Our lead compounds, singled out and optimized based on in vitro functional assay, displayed favorable pharmacokinetic and safety profiles. Furthermore, orally administered lead compound effectively suppressed tumor growth within tolerable doses in xenograft mice with tumors harboring NF2 alteration as a major upstream molecule of the Hippo pathway. In summary, we pointed our novel YAP/TAZ-TEAD inhibitors that showed excellent efficacy in Hippo-altered mutant cancer in vitro and in vivo xenograft models. These data best support a therapeutic option for the treatment of cancers with amplified or overexpressed YAP, TAZ, or TEAD genes. Further preclinical studies will be performed and reported soon after the establishment of a preclinical candidate. Citation Format: Jisook Kim, Seung Hyun Jung, Seon Yeong Han, Jihee Yoon, Minjeong Kim, Jooyun Byun, Heesun Moon, Eunyoung Lee, Yu-Yon Kim, Hyunjin Park, So-Ye Jeon, Young Gil Ahn, Young Hoon Kim, Kwee Hyun Suh. Antitumor activity of novel and potent YAP/TAZ-TEAD inhibitorstargeting the Hippo pathway in solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1614.

Microscopic calculation of the β− decays of 151Sm, 171Tm, and 210Pb with implications to detection of the cosmic neutrino background

The electron spectral shapes corresponding to the low-Qβ−-decay transitions Sm151(5/2g.s.−)→Eu151(5/2g.s.+), Sm151(5/2g.s.−)→Eu151(7/21+), Tm171(1/2g.s.+)→Yb171(1/2g.s.−), Tm171(1/2g.s.+)→Yb171(3/21−), Pb210(0g.s.+)→Bi210(1g.s.−), and Pb210(0g.s.+)→Bi210(01−) have been computed using beta-decay theory with several refinements for these first-forbidden nonunique (ff-nu) β− transitions. These ff-nu β− transitions have non-trivial electron spectral shapes with transition nuclear matrix elements (NMEs) computed by using the microscopic Interacting Boson-Fermion Model (IBFM-2) for the decays of 151Sm and 171Tm, and the nuclear shell model (NSM) for the decay of 210Pb. Within the respective Q windows, the computed ff-nu electron spectral shapes deviate maximally at sub-percent level from the universal allowed shape, except for the transition Pb210(0g.s.+)→Bi210(1g.s.−), where the maximal deviation is some 2.7%. This confirms that the so-called ξ approximation is fairly good for most of these low-Qβ− transitions and thus the allowed shape is a rather good first approximation. Our computed spectral shapes could be of interest for experiments aiming to measure the cosmic neutrino background (CνB), like the PTOLEMY experiment. We have also derived CνB cross sections for the ground-state transitions of the considered nuclei at the β endpoint. Our findings indicate that more work on the atomic mismatch correction is needed in the future in order to extract reliable and precise CνB cross sections for any nuclear target.

The molecular pharmacology of glucagon agonists in diabetes and obesity

Within recent decades glucagon receptor (GcgR) agonism has drawn attention as a therapeutic tool for the treatment of type 2 diabetes and obesity. In both mice and humans, glucagon administration enhances energy expenditure and suppresses food intake suggesting a promising metabolic utility. Therefore synthetic optimization of glucagon-based pharmacology to further resolve the physiological and cellular underpinnings mediating these effects has advanced. Chemical modifications to the glucagon sequence have allowed for greater peptide solubility, stability, circulating half-life, and understanding of the structure-function potential behind partial and “super”-agonists. The knowledge gained from such modifications has provided a basis for the development of long-acting glucagon analogues, chimeric unimolecular dual- and tri-agonists, and novel strategies for nuclear hormone targeting into glucagon receptor-expressing tissues. In this review, we summarize the developments leading toward the current advanced state of glucagon-based pharmacology, while highlighting the associated biological and therapeutic effects in the context of diabetes and obesity.

Nuclear-level effective theory of μ→e conversion: Formalism and applications

New mu-to-e conversion searches aim to advance limits on charged lepton flavor violation (CLFV) by four orders of magnitude. By considering P and CP selection rules and the structure of possible charge and current densities, we show that rates are governed by six nuclear responses. To generate a microscopic formulation of these responses, we construct in non-relativistic effective theory (NRET) the CLFV nucleon-level interaction, then embed it in a nucleus. We discuss previous work, noting the lack of a systematic treatment of the various small parameters. Because the momentum transfer is comparable to the inverse nuclear size, a full multipole expansion of the response functions is necessary, a daunting task with Coulomb-distorted electron partial waves. We perform such an expansion to high precision by introducing a simplifying local electron momentum, treating the full set of 16 NRET operators. Previous work has been limited to the simplest charge/spin operators, ignored Coulomb distortion (or alternatively truncated the partial wave expansion) and the nucleon velocity operator, which is responsible for three of the response functions. This generates inconsistencies in the treatment of small parameters. We obtain a "master formula" for mu-to-e conversion that properly treats all such effects and those of the muon velocity. We compute muon-to-electron conversion rates for a series of experimental targets, deriving bounds on the coefficients of the CLFV operators. We discuss the nuclear physics: two types of coherence enhance certain CLFV operators and selection rules blind elastic mu-to-e conversion to others. We discuss the matching of the NRET onto higher level EFTs, and the relation to mu-to-e conversion to other CLFV tests. Finally we describe a publicly available script that can be used to compute mu-to-e conversion rates in nuclear targets.

Unusual enantioselective cytoplasm-to-nucleus translocation and photosensitization of the chiral Ru(II) cationic complex via simple ion-pairing with lipophilic weak acid counter-anions.

Targeted and enantioselectivedelivery of chiral diagnostic-probes and therapeutics into specific compartments inside cells is of utmost importance in the improvement of disease detection and treatment. The classical DNA 'light-switch' ruthenium(II)-polypyridyl complex, [Ru(DIP)2(dppz)]Cl2 (DIP=4,7-diphenyl-1,10-phenanthroline, dppz=dipyridophenazine) has been shown to be accumulated only in the cytoplasm and membrane, but excluded from its intended nuclear DNA target. In this study, the cationic [Ru(DIP)2(dppz)]2+ is found to be redirected into live-cell nucleus in the presence of lipophilic 3,5-dichlorophenolate or flufenamate counter-anions via ion-pairing mechanism, while maintaining its original DNA recognition characteristics. Interestingly and unexpectedly, further studies show that only the Δ-enantiomer is selectively translocated into nucleus while the Λ-enantiomer remains trapped in cytoplasm, which is found to be mainly due to their differential enantioselective binding affinities with cytoplasmic proteins and nuclear DNA. More importantly, only the nucleus-relocalized Δ-enantiomer can induce obvious DNA damage and cell apoptosis upon prolonged visible-light irradiation. Thus, the use of Δ-enantiomer can significantly reduce the dosage needed for maximal treatment effect. This represents the first report of enantioselective targeting and photosensitization of classical Ru(II) complex via simple ion-pairing with suitable weak acid counter-anions, which opens new opportunities for more effective enantioselective cancer treatment.

Multi-Targeted and On-Demand Non-Coding RNA Regulation Nanoplatform against Metastasis and Recurrence of Triple-Negative Breast Cancer.

Dysregulation of microRNAs (miRs) is the hallmark of triple-negative breast cancer (TNBC), which is closely involved with itsgrowth, metastasis, and recurrence. Dysregulated miRs are promising targets for TNBC therapy, however, targeted and accurate regulation of multiple disordered miRs in tumors is still a great challenge. Here, a multi-targeting and on-demand non-coding RNA regulation nanoplatform (MTOR) is reported to precisely regulate disordered miRs, leading to dramatical suppression of TNBC growth, metastasis, and recurrence. With the assistance of long blood circulation, ligands of urokinase-type plasminogen activator peptide and hyaluronan located in multi-functional shells enable MTOR to actively target TNBC cells and breast cancer stem cell-like cells (BrCSCs). After entering TNBC cells and BrCSCs, MTOR is subjected to lysosomal hyaluronidase-induced shell detachment, leading to an explosion of the TAT-enriched core, thereby enhancing nuclear targeting. Subsequently, MTOR could precisely and simultaneously downregulate microRNA-21 expression and upregulate microRNA-205 expression in TNBC. In subcutaneous xenograft, orthotopic xenograft, pulmonary metastasis, and recurrence TNBC mouse models, MTOR shows remarkably synergetic effects on the inhibition of tumor growth, metastasis, and recurrence due to its on-demand regulation of disordered miRs. This MTOR system opens a new avenue for on-demand regulation of disordered miRs against growth, metastasis, and recurrence of TNBC.

Size-optimized nuclear-targeting phototherapy enhances the type I interferon response for "cold" tumor immunotherapy.

There is growing interest in the effect of innate immune silencing in "cold" tumors, which always fail in the immune checkpoint blockade monotherapy using PD-L1 monoclonal antibodies (aPD-L1). Combination of aPD-L1 with photodynamic therapy, i.e., photoimmunotherapy, is a promising strategy to improve the mono immunotherapy. Nuclear-targeting nanoparticles could elicit a type I interferon (IFN)-mediated innate immune response and reverse the immunosuppressive microenvironment for long-term immunotherapy of "cold" tumors. Photosensitizers such as zinc phthalocyanine (ZnPc) have limited ability to target the nucleus and activate innate sensing pathways to minimize tumor recurrence. Additionally, the relationship between nanoparticle size and nuclear entry capacity remains unclear. Herein, graphene quantum dots (GQDs) were employed as aPD-L1 and ZnPc carriers. Three particle sizes (200 nm, 32 nm and 5 nm) of aPD-L1/ZnPc/GQD-PEG (PZGE) were synthesized and tested. The 5 nm nanoparticles achieved the best nuclear enrichment capacity contributing to their ultrasmall size. Notably, 5 nm PZGE-based photodynamic therapy enabled an amplification of the type I IFN-mediated innate immune response and could convert "immune-cold" tumors into "immune-hot" ones. Utilizing their size advantage to target the nucleus, 5 nm nanoparticles induced DNA damage and activated the type I IFN-mediated innate immune response, subsequently promoting cytotoxic T-lymphocyte infiltration and reversing negative PD-L1 expression. Furthermore, the nanoplatform we designed is promising for the effective suppression of distant oral squamous cell carcinoma. Thus, for the first time, this study presents a size design strategy for nuclear-targeted photo-controlled immune adjuvants and the nuclear-targeted phototherapy-mediated immunomodulatory functions of type I IFN innate immune signalling for "immune-cold" tumors. STATEMENT OF SIGNIFICANCE: The potential of commonly used photosensitizers to activate innate sensing pathways for producing type I IFNs is limited due to the lack of nuclear targeting. Facilitating the nuclear-targeting of photosensitizers to enhance innate immune response and execute long-term tumor killing effect would be a promising strategy for "cold" tumor photoimmunotherapy. Herein, we report an optimal size of PZGE nanoparticles that enable the nuclear-targeting of ZnPc, which reinforces the type I IFN-mediated innate immune response, synergistically reversing "cold tumors" to "hot tumors" for effective primary and distant tumor photoimmunotherapy. This work highlights the marked efficacy of ultrasmall nuclear-located nanocarriers and offers new insight into "immune-cold tumors" via prominent innate immune activation mediated by nuclear-targeting photoimmunotherapy.

Active Nuclear Import of Mammalian Cell-Expressible DNA Origami.

DNA origami enables the creation of complex 3D shapes from genetic material. Future uses could include the delivery of genetic instructions to cells, but nuclear import remains a major barrier to gene delivery due to the impermeability of the nuclear membrane. Here we realize active nuclear import of DNA origami objects in dividing and chemically arrested mammalian cells. We developed a custom DNA origami single-strand scaffold featuring a mammalian-cell expressible reporter gene (mCherry) and multiple Simian virus 40 (SV40) derived DNA nuclear targeting sequences (DTS). Inclusion of the DTS within DNA origami rescued gene expression in arrested cells, indicating that active transport into the nucleus occurs. Our work successfully adapts mechanisms known from viruses to promote the cellular expression of genetic instructions encoded within DNA origami objects.

Analysis of nucleon-nucleus scattering data using a density-dependent semi-microscopic optical model with channel coupling

Background: The neutron scattering data was previously analyzed using a semi-microscopic optical model with channel coupling to inelastic excited states [Phys. Rev. C 100, 014603 (2019)]. The real part of the potential was constructed by single folding the density-independent M3Y-Paris bare nucleon-nucleon ($NN$) interaction, with zero-range knock-on exchange term, over the density of the target nucleus. The model reproduced the overall features of the inelastic angular distributions and polarization data. The elastic angular distributions were well reproduced.Purpose: In this work we test the effectiveness of the semi-microscopic optical model with channel coupling, but we employ a density-dependent BDM3Y1-Paris bare ($NN$) interaction, with the finite-range form of the knock-on exchange term, in describing the scattering observables, particularly, the inelastic distributions and polarization data.Method: The real volume term of the semi-microscopic model is constructed by single folding the density-dependent BDM3Y1-Paris bare ($NN$) interaction, over the matter distribution of the target nucleus. The ground state is coupled to low-lying inelastic excitation levels. The potential parameters are determined by fitting the elastic, inelastic, and polarization data corresponding to nucleon scattering off a wide range of mass numbers in the range $7\ensuremath{\le}A\ensuremath{\le}208$ for various energies from 10--95 MeV.Results: The density-dependent model resulted in significant improvements in the description of the inelastic angular distributions and analyzing power. In addition, the potential depths showed systematic linear dependence on incident energy, and one set of geometrical parameters is obtained for each nuclear target. We used our best-fit potential parameters to calculate the total cross sections corresponding to nucleon scattering off the considered nuclei. The calculated cross sections are in good agreement with the measured data.Conclusions: In a semi-microscopic optical model, construction of the real volume term by single folding the density-dependent BDM3Y1-Paris bare ($NN$) interaction, with finite form of the knock-on exchange term, results in significant improvements in reproducing the inelastic angular distributions and polarization data as compared to the case of using the density-independent M3Y-Paris bare nucleon-nucleon ($NN$) interaction, with either zero-range or finite-range exchange term.