Advocating for population health: The role of public health practitioners in the age of artificial intelligence.

Over the past decade, artificial intelligence (AI) has begun to transform Canadian organizations, driven by the promise of improved efficiency, better decision-making, and enhanced client experience. While AI holds great opportunities, there are also near-term impacts on the determinants of health and population health equity that are already emerging. If adoption is unregulated, there is a substantial risk that health inequities could be exacerbated through intended or unintended biases embedded in AI systems. New economic opportunities could be disproportionately leveraged by already privileged workers and owners of AI systems, reinforcing prevailing power dynamics. AI could also detrimentally affect population well-being by replacing human interactions rather than fostering social connectedness. Furthermore, AI-powered health misinformation could undermine effective public health communication. To respond to these challenges, public health must assess and report on the health equity impacts of AI, inform implementation to reduce health inequities, and facilitate intersectoral partnerships to foster development of policies and regulatory frameworks to mitigate risks. This commentary highlights AI's near-term risks for population health to inform a public health response.

RéSUMé: Au cours de la dernière décennie, l'intelligence artificielle (IA) a commencé à transformer les organismes canadiens en leur promettant une plus grande efficience, de meilleurs processus décisionnels et une expérience client enrichie. Bien qu'elle recèle d'immenses possibilités, l'IA aura des effets à court terme ­ qui se font d'ailleurs déjà sentir ­ sur les déterminants de la santé et sur l'équité en santé des populations. Si son adoption n'est pas réglementée, il se peut très bien que les iniquités en santé continuent d'être exacerbées par les préjugés, intentionnels ou non, ancrés dans les systèmes d'IA. Les nouvelles possibilités économiques pourraient être démesurément exploitées par les travailleurs et les travailleuses déjà privilégiés et par les propriétaires des systèmes d'IA, renforçant ainsi la dynamique de pouvoir existante. L'IA pourrait aussi nuire au bien-être des populations en remplaçant les interactions humaines au lieu de favoriser la connexité sociale. De plus, la mésinformation sur la santé alimentée par l'IA pourrait réduire l'efficacité des messages de santé publique. Pour relever ces défis, la santé publique devra évaluer et communiquer les effets de l'IA sur l'équité en santé, en modérer la mise en œuvre pour réduire les iniquités en santé, et faciliter des partenariats intersectoriels pour éclairer l'élaboration de politiques et de cadres réglementaires d'atténuation des risques. Le présent commentaire fait ressortir les risques à court terme de l'IA pour la santé des populations afin d'éclairer la riposte de la santé publique.

A Comparison Between In-Person and Virtual Communication Skills OSCE for Medical Students.

Objectives: This study investigates the effectiveness of a virtual format of an advanced communication skills observed structured clinical examination (OSCE) for senior medical students in comparison to an in-person format. The study also examines the emotional support students experience in the virtual setting. Our analysis was based on quantitative data collected through objective checklists and post-OSCE survey results. Methods: The virtual OSCE was a revision of an earlier in-person formative advanced communication skills OSCE for fourth-year medical students. Student performances were assessed by self and peers using objective checklists-the modified Master Interview Rating Scale (mMIRS) and Communication Behavior Checklist (CBC). The mMIRS measured interview process such as avoiding jargon and demonstrating empathy. The CBC examined interview content which included tasks specific to the content of the case. The OSCE was followed by a faculty-led debrief and quantitative survey. The virtual OSCE was conducted in 2021, and the results of the checklists and survey were compared with those collected from two earlier in-person OSCEs. Results: Eighty-three students participated in the virtual OSCE. There was no difference in mMIRS scores between the virtual and in-person OSCE. Overall CBC scores were lower in the virtual OSCE compared to in-person (p < 0.05). Sixty-seven out of 83 (80.7%) students completed the post-OSCE survey. There were no differences between the virtual and in-person OSCE in terms of educational value, whether the OSCE would change the way participants talk to patients, and preparedness to have serious conversations with patients. All respondents somewhat or strongly agreed with feeling emotionally supported during the virtual OSCE. Conclusion: The virtual format was a suitable alternative to an in-person, formative, advanced communication skills OSCE for medical students. The virtual OSCE was educationally effective and was met with student satisfaction and a sense of emotional support. Future virtual iterations must ensure adequate instruction on interview content.

Glycosaminoglycan modifications of betaglycan regulate ectodomain shedding to fine-tune TGF-ß signaling responses in ovarian cancer.

In pathologies including cancer, aberrant Transforming Growth Factor-ß (TGF-ß) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-ß responses. Betaglycan/type III TGF-ß receptor (TßRIII), is an established co-receptor for the TGF-ß superfamily known to bind directly to TGF-ßs 1-3 and inhibin A/B. Betaglycan can be membrane-bound and also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. Its extracellular domain undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. We report the unexpected discovery that the heparan sulfate glycosaminoglycan chains on betaglycan are critical for the ectodomain shedding. In the absence of such glycosaminoglycan chains betaglycan is not shed, a feature indispensable for the ability of betaglycan to suppress TGF-ß signaling and the cells' responses to exogenous TGF-ß ligands. Using unbiased transcriptomics, we identified TIMP3 as a key inhibitor of betaglycan shedding thereby influencing TGF-ß signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-ß signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan chains of betaglycan for shedding and influence on TGF-ß signaling responses. Dysregulated shedding of TGF-ß receptors plays a vital role in determining the response and availability of TGF-ßs', which is crucial for prognostic predictions and understanding of TGF-ß signaling dynamics.

Heparan sulfate modifications of betaglycan promote TIMP3-dependent ectodomain shedding to fine-tune TGF-ß signaling.

In pathologies such as cancer, aberrant Transforming Growth Factor-ß (TGF-ß) signaling exerts profound tumor intrinsic and extrinsic consequences. Intense clinical endeavors are underway to target this pivotal pathway. Central to the success of these interventions is pinpointing factors that decisively modulate the TGF-ß responses. Betaglycan/type III TGF-ß receptor (TßRIII), is an established co-receptor for the TGF-ß superfamily known to bind directly to TGF-ßs 1-3 and inhibin A/B. While betaglycan can be membrane-bound, it can also undergo ectodomain cleavage to produce soluble-betaglycan that can sequester its ligands. The extracellular domain of betaglycan undergoes heparan sulfate and chondroitin sulfate glycosaminoglycan modifications, transforming betaglycan into a proteoglycan. Here we report the unexpected discovery that the heparan sulfate modifications are critical for the ectodomain shedding of betaglycan. In the absence of such modifications, betaglycan is not shed. Such shedding is indispensable for the ability of betaglycan to suppress TGF-ß signaling and the cells' responses to exogenous TGF-ß ligands. Using unbiased transcriptomics, we identified TIMP3 as a key regulator of betaglycan shedding and thereby TGF-ß signaling. Our results bear significant clinical relevance as modified betaglycan is present in the ascites of patients with ovarian cancer and can serve as a marker for predicting patient outcomes and TGF-ß signaling responses. These studies are the first to demonstrate a unique reliance on the glycosaminoglycan modifications of betaglycan for shedding and influence on TGF-ß signaling responses. Dysregulated shedding of TGF-ß receptors plays a vital role in determining the response and availability of TGF-ßs', which is crucial for prognostic predictions and understanding of TGF-ß signaling dynamics.

Pathogenesis Underlying Neurological Manifestations of Long COVID Syndrome and Potential Therapeutics.

The development of long-term symptoms of coronavirus disease 2019 (COVID-19) more than four weeks after primary infection, termed "long COVID" or post-acute sequela of COVID-19 (PASC), can implicate persistent neurological complications in up to one third of patients and present as fatigue, "brain fog", headaches, cognitive impairment, dysautonomia, neuropsychiatric symptoms, anosmia, hypogeusia, and peripheral neuropathy. Pathogenic mechanisms of these symptoms of long COVID remain largely unclear; however, several hypotheses implicate both nervous system and systemic pathogenic mechanisms such as SARS-CoV2 viral persistence and neuroinvasion, abnormal immunological response, autoimmunity, coagulopathies, and endotheliopathy. Outside of the CNS, SARS-CoV-2 can invade the support and stem cells of the olfactory epithelium leading to persistent alterations to olfactory function. SARS-CoV-2 infection may induce abnormalities in innate and adaptive immunity including monocyte expansion, T-cell exhaustion, and prolonged cytokine release, which may cause neuroinflammatory responses and microglia activation, white matter abnormalities, and microvascular changes. Additionally, microvascular clot formation can occlude capillaries and endotheliopathy, due to SARS-CoV-2 protease activity and complement activation, can contribute to hypoxic neuronal injury and blood-brain barrier dysfunction, respectively. Current therapeutics target pathological mechanisms by employing antivirals, decreasing inflammation, and promoting olfactory epithelium regeneration. Thus, from laboratory evidence and clinical trials in the literature, we sought to synthesize the pathophysiological pathways underlying neurological symptoms of long COVID and potential therapeutics.

PVT1 is a stress-responsive lncRNA that drives ovarian cancer metastasis and chemoresistance.

Metastatic growth of ovarian cancer cells into the peritoneal cavity requires adaptation to various cellular stress factors to facilitate cell survival and growth. Here, we demonstrate the role of PVT1, one such stress induced long non-coding RNA, in ovarian cancer growth and metastasis. PVT1 is an amplified and overexpressed lncRNA in ovarian cancer with strong predictive value for survival and response to targeted therapeutics. We find that expression of PVT1 is regulated by tumor cells in response to cellular stress, particularly loss of cell-cell contacts and changes in matrix rigidity occurring in a YAP1-dependent manner. Induction of PVT1 promotes tumor cell survival, growth, and migration. Conversely, reducing PVT1 levels robustly abrogates metastatic behavior and tumor cell dissemination in cell lines and syngeneic transplantation models in vivo. We find that reducing PVT1 causes widespread changes in the transcriptome leading to alterations in cellular stress response and metabolic pathways including doxorubicin metabolism, which impacts chemosensitivity. Together, these findings implicate PVT1 as a promising therapeutic target to suppress metastasis and chemoresistance in ovarian cancer.

Hypoxia-induced inhibin promotes tumor growth and vascular permeability in ovarian cancers.

Hypoxia, a driver of tumor growth and metastasis, regulates angiogenic pathways that are targets for vessel normalization and ovarian cancer management. However, toxicities and resistance to anti-angiogenics can limit their use making identification of new targets vital. Inhibin, a heteromeric TGFß ligand, is a contextual regulator of tumor progression acting as an early tumor suppressor, yet also an established biomarker for ovarian cancers. Here, we find that hypoxia increases inhibin levels in ovarian cancer cell lines, xenograft tumors, and patients. Inhibin is regulated primarily through HIF-1, shifting the balance under hypoxia from activins to inhibins. Hypoxia regulated inhibin promotes tumor growth, endothelial cell invasion and permeability. Targeting inhibin in vivo through knockdown and anti-inhibin strategies robustly reduces permeability in vivo and alters the balance of pro and anti-angiogenic mechanisms resulting in vascular normalization. Mechanistically, inhibin regulates permeability by increasing VE-cadherin internalization via ACVRL1 and CD105, a receptor complex that we find to be stabilized directly by inhibin. Our findings demonstrate direct roles for inhibins in vascular normalization via TGF-ß receptors providing new insights into the therapeutic significance of inhibins as a strategy to normalize the tumor vasculature in ovarian cancer.

Establishing Goals of Care.

Establishing goals of care (GOC) is a crucial component of a patient's treatment plan. The need for better physician-patient communication in this area has been recognized for decades, yet several gaps remain. Challenges exist for both physician and patient. Physicians should pursue a patient-led approach, exercise cultural competency, and use various communication techniques to guide patients when establishing GOC.

A bioinformatic analysis of the inhibin-betaglycan-endoglin/CD105 network reveals prognostic value in multiple solid tumors.

Inhibins and activins are dimeric ligands belonging to the TGFß superfamily with emergent roles in cancer. Inhibins contain an α-subunit (INHA) and a ß-subunit (either INHBA or INHBB), while activins are mainly homodimers of either ßA (INHBA) or ßB (INHBB) subunits. Inhibins are biomarkers in a subset of cancers and utilize the coreceptors betaglycan (TGFBR3) and endoglin (ENG) for physiological or pathological outcomes. Given the array of prior reports on inhibin, activin and the coreceptors in cancer, this study aims to provide a comprehensive analysis, assessing their functional prognostic potential in cancer using a bioinformatics approach. We identify cancer cell lines and cancer types most dependent and impacted, which included p53 mutated breast and ovarian cancers and lung adenocarcinomas. Moreover, INHA itself was dependent on TGFBR3 and ENG/CD105 in multiple cancer types. INHA, INHBA, TGFBR3, and ENG also predicted patients' response to anthracycline and taxane therapy in luminal A breast cancers. We also obtained a gene signature model that could accurately classify 96.7% of the cases based on outcomes. Lastly, we cross-compared gene correlations revealing INHA dependency to TGFBR3 or ENG influencing different pathways themselves. These results suggest that inhibins are particularly important in a subset of cancers depending on the coreceptor TGFBR3 and ENG and are of substantial prognostic value, thereby warranting further investigation.

OrgDyn: feature- and model-based characterization of spatial and temporal organoid dynamics.

SUMMARY: Organoid model systems recapitulate key features of mammalian tissues and enable high throughput experiments. However, the impact of these experiments may be limited by manual, non-standardized, static or qualitative phenotypic analysis. OrgDyn is an open-source and modular pipeline to quantify organoid shape dynamics using a combination of feature- and model-based approaches on time series of 2D organoid contour images. Our pipeline consists of (i) geometrical and signal processing feature extraction, (ii) dimensionality reduction to differentiate dynamical paths, (iii) time series clustering to identify coherent groups of organoids and (iv) dynamical modeling using point distribution models to explain temporal shape variation. OrgDyn can characterize, cluster and model differences among unique dynamical paths that define diverse final shapes, thus enabling quantitative analysis of the molecular basis of tissue development and disease. AVAILABILITY AND IMPLEMENTATION: https://github.com/zakih/organoidDynamics (BSD 3-Clause License). SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.

Twist1-Induced Epithelial Dissemination Requires Prkd1 Signaling.

Dissemination is an essential early step in metastasis but its molecular basis remains incompletely understood. To define the essential targetable effectors of this process, we developed a 3D mammary epithelial culture model, in which dissemination is induced by overexpression of the transcription factor Twist1. Transcriptomic analysis and ChIP-PCR together demonstrated that protein kinase D1 (Prkd1) is a direct transcriptional target of Twist1 and is not expressed in the normal mammary epithelium. Pharmacologic and genetic inhibition of Prkd1 in the Twist1-induced dissemination model demonstrated that Prkd1 was required for cells to initiate extracellular matrix (ECM)-directed protrusions, release from the epithelium, and migrate through the ECM. Antibody-based protein profiling revealed that Prkd1 induced broad phosphorylation changes, including an inactivating phosphorylation of ß-catenin and two microtubule depolymerizing phosphorylations of Tau, potentially explaining the release of cell-cell contacts and persistent activation of Prkd1. In patients with breast cancer, TWIST1 and PRKD1 expression correlated with metastatic recurrence, particularly in basal breast cancer. Prkd1 knockdown was sufficient to block dissemination of both murine and human mammary tumor organoids. Finally, Prkd1 knockdown in vivo blocked primary tumor invasion and distant metastasis in a mouse model of basal breast cancer. Collectively, these data identify Prkd1 as a novel and targetable signaling node downstream of Twist1 that is required for epithelial invasion and dissemination. SIGNIFICANCE: Twist1 is a known regulator of metastatic cell behaviors but not directly targetable. This study provides a molecular explanation for how Twist1-induced dissemination works and demonstrates that it can be targeted. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/2/204/F1.large.jpg.

Modification of messenger RNA by 2'-O-methylation regulates gene expression in vivo.

Epitranscriptomic modifications of mRNA are important regulators of gene expression. While internal 2'-O-methylation (Nm) has been discovered on mRNA, questions remain about its origin and function in cells and organisms. Here, we show that internal Nm modification can be guided by small nucleolar RNAs (snoRNAs), and that these Nm sites can regulate mRNA and protein expression. Specifically, two box C/D snoRNAs (SNORDs) and the 2'-O-methyltransferase fibrillarin lead to Nm modification in the protein-coding region of peroxidasin (Pxdn). The presence of Nm modification increases Pxdn mRNA expression but inhibits its translation, regulating PXDN protein expression and enzyme activity both in vitro and in vivo. Our findings support a model in which snoRNA-guided Nm modifications of mRNA can regulate physiologic gene expression by altering mRNA levels and tuning protein translation.

Electronic cigarette exposures reported to the British Columbia Drug and Poison Information Centre: an observational case series.

BACKGROUND: Electronic nicotine delivery systems (ENDSs), including electronic cigarettes (e-cigarettes), are rapidly gaining popularity. The aim of this study was to use poison centre data to describe epidemiological trends in ENDS-related exposures. METHODS: We conducted an observational case series study using records containing both coded fields and free-text narratives from the British Columbia Drug and Poison Information Centre for all calls involving exposure to ENDS received from 2012 to 2017. We described trends in exposures and exposed people, as well as clinical effects. RESULTS: A total of 243 calls were recorded for 186 unique exposures to ENDS devices, e-juice, e-cigarette cartridges and other associated paraphernalia over the study period. Calls related to ENDS exposures increased nearly sixfold between 2013 and 2014 and did not decline subsequently. Exposures were most frequently documented in children aged 4 years or less (81 [43.5%]), with 58 (31.0%) in 1- and 2-year-olds. Seventy-two exposures (89%) in children aged 4 years or less were due to accidental ingestion, whereas adults aged 25 years or more called the poison centre following ENDS malfunctions (7 [23%], spills (4 [13%]) and exposure to e-juice mistaken for other substances (4 [13%]). Of the 186 exposed people, 87 (46.8%) reported symptoms. INTERPRETATION: British Columbia experienced a sixfold increase in ENDS-related calls to the provincial poison centre between 2012 and 2017, driven by ingestions in young children. Regulatory approaches aimed at minimizing children's access to ENDS, clear labelling of nicotine concentration, and packaging that reduces the likelihood of spills, product confusion and malfunction should be considered.

KRASG12C inhibition produces a driver-limited state revealing collateral dependencies.

Inhibitors targeting KRASG12C, a mutant form of the guanosine triphosphatase (GTPase) KRAS, are a promising new class of oncogene-specific therapeutics for the treatment of tumors driven by the mutant protein. These inhibitors react with the mutant cysteine residue by binding covalently to the switch-II pocket (S-IIP) that is present only in the inactive guanosine diphosphate (GDP)-bound form of KRASG12C, sparing the wild-type protein. We used a genome-scale CRISPR interference (CRISPRi) functional genomics platform to systematically identify genetic interactions with a KRASG12C inhibitor in cellular models of KRASG12C mutant lung and pancreatic cancer. Our data revealed genes that were selectively essential in this oncogenic driver-limited cell state, meaning that their loss enhanced cellular susceptibility to direct KRASG12C inhibition. We termed such genes "collateral dependencies" (CDs) and identified two classes of combination therapies targeting these CDs that increased KRASG12C target engagement or blocked residual survival pathways in cells and in vivo. From our findings, we propose a framework for assessing genetic dependencies induced by oncogene inhibition.

Use of Anticoagulation Agents After Traumatic Intracranial Hemorrhage.

OBJECTIVE: Anticoagulant therapy (ACT) after traumatic intracranial hemorrhage may lead to progression of hemorrhage, but in the presence of thromboembolic events, the clinician must decide if the benefits outweigh the risks. Currently, no data exist to guide therapy in the acute setting. METHODS: We retrospectively identified all patients admitted to our institution with traumatic intracranial hemorrhage that received intravenous heparin, full-dose enoxaparin, or warfarin during their initial hospitalization over a 3-year period. We reviewed their demographics, hospital course, clinical indication and timing for initiation of ACT, and complications. RESULTS: A total of 112 patients were identified. The median age and Glasgow Coma Scale score of these patients was 50.5 years and 9.5, respectively. Twenty-two patients required neurosurgical procedures for their presenting injury, including intracranial pressure monitors and/or open surgeries. Fifty-four patients had deep vein thrombosis or pulmonary embolism prior to initiation, and the remaining 20 patients had preexisting conditions or other indications for initiating ACT. The median time from injury to starting ACT was 8 days. Immediate complications occurred in 6 patients; however, none of these patients required a neurosurgical intervention. Delayed complications included progression of acute to chronic subdural hematoma that required intervention in 2 patients. One patient died from delayed hemorrhage. CONCLUSIONS: For this patient population, the risk of immediate and delayed intracranial hemorrhages from initiating ACT therapy in intracranial injury must be weighed against the morbidity of delaying treatment. Although further studies are needed, our review provides the first rates of complications for this patient population.

An Mtb-Human Protein-Protein Interaction Map Identifies a Switch between Host Antiviral and Antibacterial Responses.

Although macrophages are armed with potent antibacterial functions, Mycobacterium tuberculosis (Mtb) replicates inside these innate immune cells. Determinants of macrophage intrinsic bacterial control, and the Mtb strategies to overcome them, are poorly understood. To further study these processes, we used an affinity tag purification mass spectrometry (AP-MS) approach to identify 187 Mtb-human protein-protein interactions (PPIs) involving 34 secreted Mtb proteins. This interaction map revealed two factors involved in Mtb pathogenesis-the secreted Mtb protein, LpqN, and its binding partner, the human ubiquitin ligase CBL. We discovered that an lpqN Mtb mutant is attenuated in macrophages, but growth is restored when CBL is removed. Conversely, Cbl-/- macrophages are resistant to viral infection, indicating that CBL regulates cell-intrinsic polarization between antibacterial and antiviral immunity. Collectively, these findings illustrate the utility of this Mtb-human PPI map for developing a deeper understanding of the intricate interactions between Mtb and its host.

Surfactant protein-D deficiency suppresses systemic inflammation and reduces atherosclerosis in ApoE knockout mice.

AIMS: Although surfactant protein-D (SP-D) is a pneumoprotein that is predominantly synthesized by type II epithelial cells in the lung, individuals with increased circulating levels of SP-D are at an elevated risk of mortality from ischemic heart disease. Whether SP-D contributes directly to atherosclerosis is unknown. We determined the effects of SP-D gene deletion in a mouse model of atherosclerosis. METHODS AND RESULTS: SP-D knockout (KO) mice were crossed with hyperlipidemic and atherosclerosis-prone apolipoprotein E (ApoE) KO mice to generate SP-D/ApoE double knockout (DKO) mice. Mice were placed on a high-fat diet for 12 weeks beginning at 8 weeks of age. Compared with ApoE KO mice, SP-D/ApoE DKO mice had significantly less atherosclerosis with reduced macrophage accumulation, decreased local macrophage proliferation, and increased smooth muscle cell coverage in plaques. Interestingly, SP-D deficiency worsened hypercholesterolemia and induced obesity and insulin resistance but suppressed plasma interleukin-6 (IL-6) levels. SP-D deficiency also reduced blood monocytes and neutrophils counts in ApoE KO mice. CONCLUSION: SP-D deficiency reduces atherosclerosis in part by decreasing the accumulation and proliferation of macrophages and by reducing IL-6 levels systemically. SP-D is a promising therapeutic target for cachectic COPD patients with elevated circulating SP-D levels who are at increased risk of cardiovascular morbidity and mortality.

Dual-Emissive Cyclometalated Iridium(III) Polypyridine Complexes as Ratiometric Biological Probes and Organelle-Selective Bioimaging Reagents.

In this Article, we present a series of cyclometalated iridium(III) polypyridine complexes of the formula [Ir(N^C)2(N^N)](PF6) that showed dual emission under ambient conditions. The structures of the cyclometalating and diimine ligands were changed systematically to investigate the effects of the substituents on the dual-emission properties of the complexes. On the basis of the photophysical data, the high-energy (HE) and low-energy (LE) emission features of the complexes were assigned to triplet intraligand ((3)IL) and triplet charge-transfer ((3)CT) excited states, respectively. Time-dependent density functional theory (TD-DFT) calculations supported these assignments and indicated that the dual emission resulted from the interruption of the communication between the higher-lying (3)IL and the lower-lying (3)CT states by a triplet amine-to-ligand charge-transfer ((3)NLCT) state. Also, the avidin-binding properties of the biotin complexes were studied by emission titrations, and the results showed that the dual-emissive complexes can be utilized as ratiometric probes for avidin. Additionally, all the complexes exhibited efficient cellular uptake by live HeLa cells. The MTT and Annexin V assays confirmed that no cell death and early apoptosis occurred during the cell imaging experiments. Interestingly, laser-scanning confocal microscopy revealed that the complexes were selectively localized on the cell membrane, mitochondria, or both, depending on the nature of the substituents of the ligands. The results of this work will contribute to the future development of dual-emissive transition metal complexes as ratiometric probes and organelle-selective bioimaging reagents.

DLX4 is associated with orofacial clefting and abnormal jaw development.

Cleft lip and/or palate (CL/P) are common structural birth defects in humans. We used exome sequencing to study a patient with bilateral CL/P and identified a single nucleotide deletion in the patient and her similarly affected son­c.546_546delG, predicting p.Gln183Argfs*57 in the Distal-less 4 (DLX4) gene. The sequence variant was absent from databases, predicted to be deleterious and was verified by Sanger sequencing. In mammals, there are three Dlx homeobox clusters with closely located gene pairs (Dlx1/Dlx2, Dlx3/Dlx4, Dlx5/Dlx6). In situ hybridization showed that Dlx4 was expressed in the mesenchyme of the murine palatal shelves at E12.5, prior to palate closure. Wild-type human DLX4, but not mutant DLX4_c.546delG, could activate two murine Dlx conserved regulatory elements, implying that the mutation caused haploinsufficiency. We showed that reduced DLX4 expression after short interfering RNA treatment in a human cell line resulted in significant up-regulation of DLX3, DLX5 and DLX6, with reduced expression of DLX2 and significant up-regulation of BMP4, although the increased BMP4 expression was demonstrated only in HeLa cells. We used antisense morpholino oligonucleotides to target the orthologous Danio rerio gene, dlx4b, and found reduced cranial size and abnormal cartilaginous elements. We sequenced DLX4 in 155 patients with non-syndromic CL/P and CP, but observed no sequence variants. From the published literature, Dlx1/Dlx2 double homozygous null mice and Dlx5 homozygous null mice both have clefts of the secondary palate. This first finding of a DLX4 mutation in a family with CL/P establishes DLX4 as a potential cause of human clefts.

Rhenium(I) polypyridine dibenzocyclooctyne complexes as phosphorescent bioorthogonal probes: Synthesis, characterization, emissive behavior, and biolabeling properties.

We report the development of rhenium(I) polypyridine complexes appended with a dibenzocyclooctyne (DIBO) moiety as bioorthogonal probes for azide-modified biomolecules. Three phosphorescent rhenium(I) polypyridine DIBO complexes [Re(N^N)(CO)3(py-C6-DIBO)][CF3SO3] (py-C6-DIBO=3-(N-(6-(3,4:7,8-dibenzocyclooctyne-5-oxycarbonylamino)hexyl)aminocarbonyl)pyridine; N^N=1,10-phenanthroline (phen) (1a), 3,4,7,8-tetramethyl-1,10-phenanthroline (Me4-phen) (2a), 4,7-diphenyl-1,10-phenanthroline (Ph2-phen) (3a)) and their DIBO-free counterparts [Re(N^N)(CO)3(py-C6-BOC)][CF3SO3] (py-C6-BOC=3-(N-(6-(tert-butoxycarbonylamino)hexyl)aminocarbonyl)pyridine; N^N=phen (1b), Me4-phen (2b), Ph2-phen (3b)) were synthesized and characterized. Upon photoexcitation, all the complexes displayed intense and long-lived yellow triplet metal-to-ligand charge-transfer ((3)MLCT) (dπ(Re)→π*(N^N)) emission. The DIBO complexes underwent facile reactions with benzyl azide in methanol at 298 K with second-order rate constants (k2) in the range of 0.077 to 0.091 M(-1) s(-1). As revealed from SDS-PAGE analysis, the DIBO complexes can selectively label azide-modified proteins and the resulting bioconjugates displayed strong phosphorescence upon photoexcitation. Results of inductively coupled plasma mass spectrometry (ICP-MS) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays indicated that the DIBO complexes accumulated in Chinese Hamster Ovary (CHO) cells with considerable cytotoxic activity. Upon incubation of CHO cells with these complexes, relatively weak intracellular emission was observed. In contrast, upon pretreatment of the cells with 1,3,4,6-tetra-O-acetyl-N-azidoacetyl-D-mannosamine (Ac4ManNAz), intense emission was observed from the cell membrane and some internal compartments. The results suggest that the DIBO complexes are promising candidates for imaging azide-labeled biomolecules.