Investigation of the Biological Impact of Charge Distribution on a NTR1-Targeted Peptide

The neurotensin receptor 1 (NTR1) has been shown to be a promising target, due to its increased level of expression relative to normal tissue, for pancreatic and colon cancers. This has prompted the development of a variety of NTR1-targeted radiopharmaceuticals, based on the neurotensin (NT) peptide, for diagnostic and radiotherapeutic applications. A major obstacle for the clinical translation of NTR1-targeted radiotherapeutics would likely be nephrotoxicity due to the high levels of kidney retention. It is well-known that for many peptide-based agents, renal uptake is influenced by the overall molecular charge. Herein, we investigated the effect of charge distribution on receptor binding and kidney retention. Using the [(N-α-Me)­Arg⁸,Dmt¹¹,Tle¹²]­NT­(6–13) targeting vector, three peptides (¹⁷⁷Lu–K2, ¹⁷⁷Lu–K4, and ¹⁷⁷Lu–K6), with the Lys moved closer (K6) or further away (K2) from the pharmacophore, were synthesized. In vitro competitive binding, internalization and efflux, and confocal microscopy studies were conducted using the NTR1-positive HT-29, human colon cancer cell line. The ^177/natLu–K6 demonstrated the highest binding affinity (21.8 ± 1.2 nM) and the highest level of internalization (4.06% ± 0.20% of the total added amount). In vivo biodistribution, autoradiography, and metabolic studies of ¹⁷⁷Lu-radiolabeled K2, K4, and K6 were examined using CF-1 mice. ¹⁷⁷Lu–K4 and ¹⁷⁷Lu–K6 gave the highest levels of in vivo uptake in NTR1-positive tissues, whereas ¹⁷⁷Lu–K2 yielded nearly 2-fold higher renal uptake relative to the other radioconjugates. In conclusion, the position of the Lys (positively charged amino acid) influences the receptor binding, internalization, in vivo NTR1-targeting efficacy, and kidney retention profile of the radioconjugates. In addition, we have found that hydrophobicity likely play a role in the unique biodistribution profiles of these agents

Theoretical Studies of Photodeactivation Pathways of NHC–Chelate Pt(II) Compounds with Different Numbers of Triarylboron Units: Radiative and Nonradiative Decay Processes

The radiative and nonradiative decay processes of four platinum­(II) complexes chelated with triarylboron (TAB)-functionalized N-heterocyclic carbenes (NHC) are investigated by using density functional theory (DFT) and time-dependent DFT (TD-DFT) calculation, for probing into the influence of different numbers of TAB on the phosphorescent emission properties. For the radiative decay processes, zero-field splitting energies, radiative rates, and lifetimes are explored, and corresponding factors including transition dipole moments, singlet–triplet splitting energies as well as spin–orbit coupling matrix elements are also analyzed in detail. Additionally, energy-gap law is considered in the temperature-independent nonradiative decay processes; meanwhile, potential energy profiles are obtained to elaborate the temperature-dependent nonradiative decay processes. As a result, radiative rates declined slightly with the increased numbers of TAB. The minimum temperature-independent nonradiative decay may occur in BC-3 due to its smallest structural distortion between S₀ and T₁ states. According to the potential energy profiles of the deactivation pathways, four investigated phosphors have the similar temperature-dependent nonradiative decay processes because of the incredibly analogous energy barriers. We speculate that it does not mean greater phosphorescent emission and higher phosphorescent quantum yield with more TAB units, which would provide extraordinary assistance for further research in potential phosphors of organic light-emitting diodes

Investigation into the Biological Impact of Block Size on Cathepsin S‑Degradable HPMA Copolymers

<i>N</i>-(2-Hydroxypropyl)­methacrylamide (HPMA) copolymers have been studied as an efficient carrier for drug delivery and tumor imaging. However, as with many macromolecular platforms, the substantial accumulation of HPMA copolymer by the mononuclear phagocyte system (MPS)-associated tissues, such as the blood, liver, and spleen, has inhibited its clinical translation. Our laboratory is pursuing approaches to improve the diagnostic and radiotherapeutic effectiveness of HPMA copolymers by reducing the nontarget accumulation. Specifically, we have been investigating the use of a cathepsin S (Cat S)-cleavable peptidic linkers to degrade multiblock HPMA copolymers to increase MPS-associated tissue clearance. In this study, we further our investigation into this area by exploring the impact of copolymer block size on the biological performance of Cat S-degradable HPMA copolymers. Using a variety of <i>in vitro</i> and <i>in vivo</i> techniques, including dual labeling of the copolymer and peptide components, we investigated the constructs using HPAC pancreatic ductal adenocarcinoma models. The smaller copolymer block size (S-CMP) demonstrated significantly faster Cat S cleavage kinetics relative to the larger system (L-CMP). Confocal microscopy demonstrated that both constructs could be much more efficiently internalized by human monocyte-differentiated macrophage (hMDM) compared to HPAC cells. In the biodistribution studies, the multiblock copolymers with a smaller block size exhibited faster clearance and lower nontarget retention while still achieving good tumor targeting and retention. Based on the radioisotopic ratios, fragmentation and clearance of the copolymer constructs were higher in the liver compared to the spleen and tumor. Overall, these results indicate that block size plays an important role in the biological performance of Cat S-degradable polymeric constructs

Arterial blood gas and biochemical analysis.

<p>A: pH; B: PaCO₂; C: PaO₂; D: Blood lactate concentration; E: Blood glucose concentration. FiO₂: fraction of inspired oxygen; PaCO₂: partial pressure of carbon dioxide; PaO₂: partial pressure of oxygen. Sevo treatment could decrease pH (A) due to hypercarbia (B) and increase the blood glucose concentration; n = 3 at each time.</p

Single-Atom Catalysts Mediated Bioorthogonal Modulation of N⁶‑Methyladenosine Methylation for Boosting Cancer Immunotherapy

Bioorthogonal reactions provide a powerful tool to manipulate biological processes in their native environment. However, the transition-metal catalysts (TMCs) for bioorthogonal catalysis are limited to low atomic utilization and moderate catalytic efficiency, resulting in unsatisfactory performance in a complex physiological environment. Herein, sulfur-doped Fe single-atom catalysts with atomically dispersed and uniform active sites are fabricated to serve as potent bioorthogonal catalysts (denoted as Fe-SA), which provide a powerful tool for in situ manipulation of cellular biological processes. As a proof of concept, the N6-methyladensoine (m6A) methylation in macrophages is selectively regulated by the mannose-modified Fe-SA nanocatalysts (denoted as Fe-SA@Man NCs) for potent cancer immunotherapy. Particularly, the agonist prodrug of m6A writer METTL3/14 complex protein (pro-MPCH) can be activated in situ by tumor-associated macrophage (TAM)-targeting Fe-SA@Man, which can upregulate METTL3/14 complex protein expression and then reprogram TAMs for tumor killing by hypermethylation of m6A modification. Additionally, we find the NCs exhibit an oxidase (OXD)-like activity that further boosts the upregulation of m6A methylation and the polarization of macrophages via producing reactive oxygen species (ROS). Ultimately, the reprogrammed M1 macrophages can elicit immune responses and inhibit tumor proliferation. Our study not only sheds light on the design of single-atom catalysts for potent bioorthogonal catalysis but also provides new insights into the spatiotemporal modulation of m6A RNA methylation for the treatment of various diseases

Perinatal n-3 PUFAs supplementation improves neonatal sevoflurane exposure induced neurobehavioral impairment at adulthood (n = 9 each group).

<p>A–D Morris water maze spatial reference memory. Latency to platform in learning phase (A); Frequency to across the platform region (B); Swimming distance during the probe trial (C); Swimming speed during the probe trial (D); **<i>p</i> = 0.0019 control vs. Sevo. Fear conditioning (E–G). Post shock freezing (E): post shock 1 (F = 29.437, <i>p</i> = 0.0041, one-way ANOVA, Newman-Keul post hoc test, *<i>p</i><0.05 control vs. Sevo; #<i>p</i><0.05 Sevo vs. Sevo+n-3 PUFAs); post shock 2 (F = 10.3, <i>p</i> = 0.0033, one-way ANOVA, Newman-Keul post hoc test, *<i>p</i><0.05 control vs. Sevo group; #<i>p</i><0.05 Sevo vs. Sevo+n-3 PUFAs). Tone freezing (F); Context freezing (G); Morris water maze memory consolidation (H–K): Latency to platform in learning phase (H); Escape latency at 1-min delay (I) F = 10.25, <i>p</i> = 0.0031, one-way ANOVA, Newman-Keul post hoc test,**<i>p</i><0.01 control vs. Sevo, ##<i>p</i><0.01 Sevo vs. Sevo+n-3 PUFAs; Escape latency at 1-h delay (J); F = 13.70, <i>p</i> = 0.0014, one-way ANOVA, Newman-Keul post hoc test, **<i>p</i><0.01 control vs. Sevo ##<i>p</i><0.01 Sevo vs. Sevo+n-3 PUFAs; Escape latency at 4-h delay (K).</p

The effects of neonatal sevoflurane exposure on caspase-3 expression.

<p>Immunofluorescence revealed the effects of the 6-h 3% sevoflurane exposure on cleaved caspase-3 expression in neonatal rat brains at P7 (n = 3 in each group). The photomicrographs (5×) of cleaved caspase-3 in the parietal cortex in control group (A) and in the Sevo group (B); C: The photomicrographs (5× with 20× inset) of cleaved caspase-3 in the parietal cortex in control group (C) and in the Sevo group (D); Quantification of cleaved caspase-3 in parietal cortex (control vs. Sevo, <i>p</i> = 0.0389) (E); The photomicrographs (10×) of cleaved caspase-3 in the CA1 (F), CA3 (H) of controls and CA1 (G), CA3 (I) in Sevo group; Quantification of cleaved caspase-3 in hippocampus region (control vs. Sevo, NS) (J); Photomicrographs (10×) of cleaved caspase-3 in the thalamus in control group (K) and in Sevo group (L); Quantification of cleaved caspase-3 in the thalamus region (control vs. Sevo, <i>p</i> = 0.0002) (M).</p

Morris water maze setup.

<p>Numbers: platform location; Letters: drop location. In the spatial reference memory task, the platform location is in the middle of one of four virtual quadrants (2). In the probe training session, the rat are released from four pseudorandomly assigned points (D,E,H and G) which provide two short and two medium swims to the platform location per session. In the probe test session, the drop location (F) is at the opposite of original platform. In the memory consolidation task, the platform location are quarter-way between the center of the maze and the wall of the tank on the border of two quadrants (1) or within a quadrant (4), or in the center of the maze (3) or in the middle of one of four virtual quadrants (2). The drop location was pseudorandomly varied to incorporate one short, one medium, and one long swim to platform.</p

Additional file 7: Figure S2. of Microarray analysis of long non-coding RNA expression profiles uncovers a Toxoplasma-induced negative regulation of host immune signaling

Transfection of shRNA-NONHSAT022487 into HFF and THP-1 cells. (TIFF 972 kb

Additional file 1: Table S1. of Microarray analysis of long non-coding RNA expression profiles uncovers a Toxoplasma-induced negative regulation of host immune signaling

A list of primer sequences used for the real-time qPCR detection. (XLSX 11 kb