A G-quadruplex-binding platinum complex induces cancer mitochondrial dysfunction through dual-targeting mitochondrial and nuclear G4 enriched genome.

BACKGROUND: G-quadruplex DNA (G4) is a non-canonical structure forming in guanine-rich regions, which play a vital role in cancer biology and are now being acknowledged in both nuclear and mitochondrial (mt) genome. However, the impact of G4-based targeted therapy on both nuclear and mt genome, affecting mt function and its underlying mechanisms remain largely unexplored. METHODS: The mechanisms of action and therapeutic effects of a G4-binding platinum(II) complex, Pt-ttpy, on mitochondria were conducted through a comprehensive approaches with in vitro and in vivo models, including ICP-MS for platinum measurement, PCR-based genetic analysis, western blotting (WB), confocal microscope for mt morphology study, extracellular flux analyzer, JC1 and Annexin V apoptosis assay, flow cytometry and high content microscope screening with single-cell quantification of both ROS and mt specific ROS, as well as click-chemistry for IF study of mt translation. Decipher Pt-ttpy effects on nuclear-encoded mt related genes expression were undertaken via RNA-seq, Chip-seq and CUT-RUN assays. RESULTS: Pt-ttpy, shows a highest accumulation in the mitochondria of A2780 cancer cells as compared with two other platinum(II) complexes with no/weak G4-binding properties, Pt-tpy and cisplatin. Pt-ttpy induces mtDNA deletion, copy reduction and transcription inhibition, hindering mt protein translation. Functional analysis reveals potent mt dysfunction without reactive oxygen species (ROS) induction. Mechanistic study provided first evidence that most of mt ribosome genes are highly enriched in G4 structures in their promoter regions, notably, Pt-ttpy impairs most nuclear-encoded mt ribosome genes' transcription through dampening the recruiting of transcription initiation and elongation factors of NELFB and TAF1 to their promoter with G4-enriched sequences. In vivo studies show Pt-ttpy's efficient anti-tumor effects, disrupting mt genome function with fewer side effects than cisplatin. CONCLUSION: This study underscores Pt-ttpy as a G4-binding platinum(II) complex, effectively targeting cancer mitochondria through dual action on mt and nuclear G4-enriched genomes without inducing ROS, offering promise for safer and effective platinum-based G4-targeted cancer therapy.

Low exposition to lithium prevents nephrogenic diabetes insipidus but not microcystic dilations of the collecting ducts in long-term rat model.

Lithium induces nephrogenic diabetes insipidus (NDI) and microcystic chronic kidney disease (CKD). As previous clinical studies suggest that NDI is dose-dependent and CKD is time-dependent, we investigated the effect of low exposition to lithium in a long-term experimental rat model. Rats were fed with a normal diet (control group), with the addition of lithium (Li+ group), or with lithium and amiloride (Li+/Ami group) for 6 months, allowing obtaining low plasma lithium concentrations (0.25 ± 0.06 and 0.43 ± 0.16 mmol/L, respectively). Exposition to low concentrations of plasma lithium levels prevented NDI but not microcystic dilations of kidney tubules, which were identified as collecting ducts (CDs) on immunofluorescent staining. Both hypertrophy, characterized by an increase in the ratio of nuclei per tubular area, and microcystic dilations were observed. The ratio between principal cells and intercalated cells was higher in microcystic than in hypertrophied tubules. There was no correlation between AQP2 messenger RNA levels and cellular remodeling of the CD. Additional amiloride treatment in the Li+/Ami group did not allow consistent morphometric and cellular composition changes compared to the Li+ group. Low exposition to lithium prevented overt NDI but not microcystic dilations of the CD, with differential cellular composition in hypertrophied and microcystic CDs, suggesting different underlying cellular mechanisms.

Scurvy complicated with Capnocytophaga sputigena sepsis as a possible cause of death of king Saint-Louis of France (1270 AD).

The cause of death of Saint-Louis is not known, but recent findings indicated that he presented scurvy and inflammatory jaw disease, which has been associated with infection by oral commensals. Here, we have the exceptional opportunity to analyze the relics of the viscera of King Saint-Louis. A 4.3 g sample from the viscera relics of King Saint-Louis conserved in Versailles' cathedral was subjected to radiocarbon dating, electronic and optic microscopy, and elementary, palynological, molecular, proteomics and microbiological analyses including specific PCR and v3v4 16 S rRNA gene amplification prior to large-scale sequencing using an Illumina MiSeq instrument. The measured radiocarbon age was Cal 1290 CE-1400, which was compatible with that of the viscera of St Louis viscera, considering the addition of lime, incense and vegetables within the human organs. Elemental and palynological analyses confirmed a medieval embalming process. Proteomics analysis identified mainly human muscle and blood proteins. Specific PCR for plague, amoebiasis, shigellosis and typhoid fever was negative. C. sputigena was identified as the main pathogenic species representing 10.8 % of all microbial sequences. In contrast, C. sputigena was found in only 0.001 % of samples sequenced in our center, and the 23 positive human samples showed a dramatically lower abundance (0.02-2.6 %). In the literature, human infections with C. sputigena included odontitis, dental abscess, sinusitis, thoracic infections and bacteremia, particularly in immunocompromised patients with oral and dental diseases consistent with recent analysis of King Saint-Louis' jaw. C. sputigena, a commensal of the mouth that is potentially pathogenic and responsible for fatal bacteremia, may have been the cause of the king's death.

Parenteral Zinc Intake in Newborns With Jejunostomy or Ileostomy: Results of a Monocentric Cohort Study.

OBJECTIVES: The aim of the study was to assess zinc status of newborns with parenteral nutrition with or without a small bowel stoma, to determine the incidence of zinc deficit, and to determine the clinical factors associated with plasma zinc levels. METHODS: Monocentric cohort study including all liveborn infants receiving zinc parenteral intake at 500 µg ·â€Škg ·â€Šday and who benefited from at least 1 plasma zinc assessment during hospitalization. RESULTS: Sixty-eight dosages of zinc were performed in 50 newborns, divided into 3 groups (no stoma = 26, jejunostomy = 11, ileostomy = 13). Thirty-seven of the 50 infants were born preterm. The mean ± standard deviation plasma zinc was 14.9 ±â€Š4.3 µmol/L and was similar among the 3 groups. Sixty-four percent, 3%, and 34% of zinc values were within, below, and above the normal range, respectively. In infants with jejunostomy, only 1 plasma zinc value (5%) was below the reference range. Plasma zinc levels were negatively correlated with stoma output (r = -0.449; P = 0.013). In contrast to patients with limited intestinal losses (ie, no stoma and ileostomy groups) no association between zinc levels and postmenstrual age was observed in infants with a jejunostomy suggesting that 500 µg ·â€Škg ·â€Šday was adequate not only in preterm infants but also in term infants with a jejunostomy. CONCLUSION: Plasma zinc levels decrease significantly with the increase of stoma output volume of newborns with small bowel stoma. Zinc deficit was prevented in newborns with a small bowel stoma receiving of 500 µg ·â€Škg ·â€Šday of parenteral zinc.

Sodium Transporters Are Involved in Lithium Influx in Brain Endothelial Cells.

Variability in drug response to lithium (Li+) is poorly understood and significant, as only 40% of patients with bipolar disorder highly respond to Li+. Li+ can be transported by sodium (Na+) transporters in kidney tubules or red blood cells, but its transport has not been investigated at the blood-brain barrier (BBB). Inhibition and/or transcriptomic strategies for Na+ transporters such as NHE (SLC9), NBC (SLC4), and NKCC (SLC12) were used to assess their role on Li+ transport in human brain endothelial cells. Na+-free buffer was also used to examine Na+/Li+ countertransport (NLCT) activity. The BBB permeability of Li+ evaluated in the rat was 2% that of diazepam, a high passive diffusion lipophilic compound. Gene expression of several Na+ transporters was determined in hCMEC/D3 cells, human hematopoietic stem-cell-derived BBB models (HBLEC), and human primary brain microvascular endothelial cells (hPBMECs) and showed the following rank order with close expression profile: NHE1 > NKCC1 > NHE5 > NBCn1, while NHE2-4, NBCn2, and NBCe1-2 were barely detected. Li+ influx in hCMEC/D3 cells was increased in Na+-free buffer by 3.3-fold, while depletion of chloride or bicarbonate had no effect. DMA (NHE inhibitor), DIDS (anionic carriers inhibitor), and bumetanide (NKCC inhibitor) decreased Li+ uptake significantly in hCMEC/D3 by 52, 51, and 47%, respectively, while S0859 (NBC inhibitor) increased Li+ influx 2.3-fold. Zoniporide (NHE1 inhibitor) and siRNA against NHE1 had no effect on Li+ influx in hCMEC/D3 cells. Our study shows that NHE1 and/or NHE5, NBCn1, and NKCC1 may play a significant role in the transport of Li+ through the plasma membrane of brain endothelial cells.

Outcomes after revision of metal on metal hip resurfacing to total arthroplasty using the direct anterior approach.

BACKGROUND: Function after revision total hip arthroplasty (THA) in failed metal-on-metal (MoM) hip resurfacing arthroplasty (HRA) is variable, but post-operative complication rates are reportedly high. We hypothesized HRA conversion to THA using the direct anterior approach (DAA) would be associated with optimal outcome. METHODS: Seventeen MoM-HRAs in 15 patients (seven males, eight females) were revised through the DAA. The mean age was 45 years (28-59 yrs). The most common indications for revision were aseptic loosening of the acetabular component or of the femoral component and femoral neck fracture. In 16 hips, a conversion to a ceramic-on-ceramic (CoC) (13 hips) or to a metal-on polyethylene (MOP) (2), or to a large-head MoM (1) THA was done. An isolated femoral revision was done in one hip. RESULTS: After 6.7 ± 3 years, no hip had required a re-revision. The Postel-Merle d'Aubigne (PMA) functional score improved from 9 (4-14) to 16 (12-18) (p < 0.001). An intra-operative fracture of the greater trochanter (one hip) and dysesthesia of the lateral femoral cutaneous nerve (four hips) were reported. Mean serum chromium concentration decreased from 33.2 µg/L (11.8-62 µg/L) pre-operatively to 5.8 µg/L (0.4-35.5 µg/L) post-operatively (p < 0.001), and mean serum cobalt concentration decreased from 35.8 µg/L (6.3-85.5 µg/L) to 4.7 µg/L (0.26-25.7 µg/L) (p = 0.003). CONCLUSION: Revision of failed MoM-HRA using the DAA resulted in an acceptable clinical outcome, no specific complication and no further surgery. A consistent decline in serum ion levels may be expected following HRA conversion to THA.

Platinum Complexes Can Bind to Telomeres by Coordination.

It is suggested that several compounds, including G-quadruplex ligands, can target telomeres, inducing their uncapping and, ultimately, cell death. However, it has never been demonstrated whether such ligands can bind directly and quantitatively to telomeres. Here, we employed the property of platinum and platinum-G-quadruplex complexes to target G-rich sequences to investigate and quantify their covalent binding to telomeres. Using inductively coupled plasma mass spectrometry, surprisingly, we found that, in cellulo, in the presence of cisplatin, a di-functional platinum complex, telomeric DNA was platinated 13-times less than genomic DNA in cellulo, as compared to in vitro data. On the contrary, the amount of mono-functional platinum complexes (Pt-ttpy and Pt-tpy) bound either to telomeric or to genomic DNA was similar and occurred in a G-quadruplex independent-manner. Importantly, the quantification revealed that the low level of cisplatin bound to telomeric DNA could not be the direct physical cause of TRF2 displacement from telomeres. Altogether, our data suggest that platinum complexes can affect telomeres both directly and indirectly.

Investigation of lithium distribution in the rat brain ex vivo using lithium-7 magnetic resonance spectroscopy and imaging at 17.2 T.

Lithium is the first-line mood stabilizer for the treatment of patients with bipolar disorder. However, its mechanisms of action and transport across the blood-brain barrier remain poorly understood. The contribution of lithium-7 magnetic resonance imaging (7 Li MRI) to investigate brain lithium distribution remains limited because of the modest sensitivity of the lithium nucleus and the expected low brain concentrations in humans and animal models. Therefore, we decided to image lithium distribution in the rat brain ex vivo using a turbo-spin-echo imaging sequence at 17.2 T. The estimation of lithium concentrations was performed using a phantom replacement approach accounting for B1 inhomogeneities and differential T1 and T2 weighting. Our MRI-derived lithium concentrations were validated by comparison with inductively coupled plasma-mass spectrometry (ICP-MS) measurements ([Li]MRI  = 1.18[Li]MS , R = 0.95). Overall, a sensitivity of 0.03 mmol/L was achieved for a spatial resolution of 16 µL. Lithium distribution was uneven throughout the brain (normalized lithium content ranged from 0.4 to 1.4) and was mostly symmetrical, with consistently lower concentrations in the metencephalon (cerebellum and brainstem) and higher concentrations in the cortex. Interestingly, low lithium concentrations were also observed close to the lateral ventricles. The average brain-to-plasma lithium ratio was 0.34 ± 0.04, ranging from 0.29 to 0.39. Brain lithium concentrations were reasonably correlated with plasma lithium concentrations, with Pearson correlation factors ranging from 0.63 to 0.90.

Association of a Platinum Complex to a G-Quadruplex Ligand Enhances Telomere Disruption.

Telomeres protect the ends of chromosomes against illegitimate recombination and repair. They can be targets for G-quadruplex ligands and platinum complexes due to their repeated G-rich sequences. Protection of telomeres is ensured by a complex of six proteins, including TRF2, which inhibits the DNA damage response pathway. We analyzed telomere modifications induced in cancer cells by the experimental hybrid platinum complex, Pt-MPQ, comprising both an ethylene diamine monofunctional platinum complex and a G-quadruplex recognition moiety (MPQ). Pt-MPQ promotes the displacement of two telomeric proteins (TRF2 and TRF1) from telomeres, as well as the formation of telomere damage and telomere sister losses, whereas the control compound MPQ does not. This suggests that the platinum moiety potentiates the targeting of the G-quadruplex ligand to telomeres, opening a new perspective for telomere biology and anticancer therapy. Interestingly, the chemotherapy drug cisplatin, which has no specific affinity for G-quadruplex structures, partially induces the TRF2 delocalization from telomeres but produces less telomeric DNA damage, suggesting that this TRF2 displacement could be independent of G-quadruplex recognition.