The rockefeller university

Radioimmunotherapy using Ac-225, a highly cytotoxic alpha-particle emitter, has potential for treating advanced breast cancer, especially human epidermal growth factor receptor 2 (HER2)-positive cases. We use a pretargeted radioimmunotherapy (PRIT) approach consisting of a 3-step intravenous regimen (step 1: bispecific anti-HER2/anti-DOTA antibody; step 2: clearing agent; step 3: Ac-225-radiolabeled Proteus DOTA, or [Ac-225]Ac-Pr). Our goal was to establish curative Ac-225-PRIT with high therapeutic indices. Methods: The impact of [Ac-225]Ac-Pr specific activity was evaluated in the BT-474 breast xenograft model. We tested the effects of [Ac-225]Ac-Pr dosing during PRIT on tumor-targeting efficiency and tissue biodistribution. Using a Ac-225-PRIT regimen consisting of a ratio of 1.19 nmol of bispecific antibody to 0.60-0.66 nmol of [Ac-225]Ac-Pr, we evaluated therapy in the BT-474 model and a patient-derived xenograft model. BT-474-tumor-bearing mice were treated with 1 or 2 cycles of Ac-225-PRIT (37 kBq/cycle) separated by 1 wk. A dose escalation study was performed on the BT-474 model to establish an absorbed radiation dose of approximately 40 Gy (relative biological effectiveness [RBE], 5) as a nephrotoxic dose, as no such histologic findings were observed in prior studies at the 20.7-Gy (RBE, 5) renal dose level. Results: In the BT-474 model, 100% (20/20) achieved complete responses and histologic cure in 17 of 20 (85%) of the treated animals. One-cycle and 2-cycle treatments were equally effective. Treatments were well tolerated, with no chronic radiation toxicity documented during necropsy at 175 d. Dosimetry estimates (RBE, 5) per 37 kBq administered for tumors and kidneys were 210 and 3.5 Gy, respectively. In the patient-derived xenograft model, a single Ac-225-PRIT treatment led to 60% (3/5) complete response and prolonged survival (>93 d) versus no treatment (30 d; P = 0.0185). Lastly, a Ac-225-PRIT regimen was identified that induces severe chronic nephrotoxicity (41.4 Gy/592 kBq; RBE, 5). Conclusion: Safe and effective Ac-225-PRIT regimens were developed in 2 preclinical models of advanced HER2-positive human breast cancer with tumor cure without dose-limiting nephrotoxicity. This study establishes crucial preclinical dosimetry benchmarks for Ac-225-PRIT and provides a compelling rationale for its advancement into the clinic.

The synaptic vesicle glycoprotein 2A (SV2A), a member of the major facilitator superfamily (MFS), is a key target for antiseizure medications and a biomarker for synaptic density imaging. Despite its clinical importance, the mechanisms underlying SV2A ligand binding and modulation remain poorly understood. Here, we report sub-3 & Aring; resolution cryo-electron microscopy (cryo-EM) structures of human SV2A in its apo form and in complex with FDA-approved antiseizure medication levetiracetam; PET imaging tracer UCB-J; experimental antiseizure drug padsevonil; and allosteric modulator UCB1244283. We find that levetiracetam and UCB-J induce vestibule occlusion, a hallmark conformational transition of MFS transporters that had not been observed in previous SV2A structures. UCB1244283 binds to an allosteric site and enhances orthosteric ligand engagement by stabilizing the occluded state and slowing ligand dissociation. Notably, padsevonil occupies both orthosteric and allosteric sites, functionally precluding modulation. These findings uncover an allosteric mechanism of regulation and provide a structural framework for the development of modulators targeting SV2A and related MFS transporters.

The ability to precisely control gene expression using small-molecule drugs is a valuable tool in research and has important therapeutic potential. However, existing systems are often limited by the toxicity of the drugs and the need to alter gene sequences or endogenous regulatory elements. Here, we introduce Cyclone (acyclovir-controlled poison exon), an acyclovir-controlled poison exon cassette that can be used for small-molecule control of both transgene and endogenous gene expression. Cyclone is a portable 'intron-poison exon-intron' element that can be inserted into nearly any gene and is completely removed upon acyclovir treatment, leaving the native transcript intact. Cyclone offers tunable, reversible gene expression with nearly undetectable background and a similar to 295-fold activation. We also present Pac-Cyclone, a cassette that simplifies the generation of cell lines with acyclovir-controlled endogenous gene expression. Finally, we demonstrate the programmability of Cyclone, underscoring its potential for developing diverse genetic circuits controlled by various ligands.

Taylor's power law of fluctuation scaling has been well approximated empirically in many fields, including physics, meteorology, computer science, finance and ecology. In ecology, it describes well the abundances of many species, humans and non-humans. Taylor's law asserts that, in a collection of probability distributions, the variance of each distribution is directly proportional to a power of the mean of each distribution, exactly for population moments and, whether or not population moments exist, approximately for sample moments. Linear regression of log variance as a function of log mean is widely used to estimate the parameters of Taylor's power law. We provide large-sample asymptotics for this kind of inference under general conditions, and we derive confidence intervals for the parameters. In many ecological applications, the means and variances are estimated over time or across space from arrays of abundance data collected at different locations and time points. Our results depend on the asymptotic relation between the time-series length and the number of spatial points. When their ratio converges to a constant as both become large, the usual normalized statistics are asymptotically biased. We provide a bias correction to get correct confidence intervals. Taylor's law, widely studied in multiple sciences, is a source of challenging new statistical problems in a non-stationary spatio-temporal framework. We illustrate our results with both simulated and real data.

Regulatory T (Treg) cells, expressing the transcription factor Foxp3, are obligatory gatekeepers of immune responsiveness, yet the mechanisms by which Foxp3 governs the Treg transcriptional network remain incompletely understood. Using a novel chemogenetic system of inducible Foxp3 protein degradation in vivo, we found that while Foxp3 was indispensable for the establishment of transcriptional and functional programs of newly generated Treg cells, Foxp3 loss in mature Treg cells resulted in minimal functional and transcriptional changes under steady state. This resilience of the Foxp3-dependent program in mature Treg cells was acquired over an unexpectedly long timescale; however, in settings of severe inflammation, Foxp3 loss led to a pronounced perturbation of Treg cell transcriptome and fitness. Furthermore, tumoral Treg cells were uniquely sensitive to Foxp3 degradation, which led to impairment in their suppressive function and tumor shrinkage in the absence of pronounced adverse effects. These studies demonstrate a context-dependent differential requirement for Foxp3 for Treg transcriptional and functional programs.

QuestionCan an education and communication-based intervention improve knowledge and caregiving self-efficacy among home health aides and attendants (HHAs) caring for adults with heart failure (HF)?FindingsIn this pilot randomized clinical trial including 102 agency-employed HHAs randomized to training alone or in addition to an application that allowed HHAs to exchange text messages with nurse supervisors, training improved HHAs' HF knowledge and HF caregiving self-efficacy. The addition of the application did not improve these primary outcomes, but it significantly reduced HHAs' self-reported preventable 911 calls, a secondary outcome.MeaningThese results support a future RCT that will test the effectiveness of the intervention on outcomes for both HHAs and their patients with HF. This pilot randomized clinical trial examines the effectiveness of an education- and communication-based intervention among home health aides caring for patients with heart failure. ImportanceHome health aides (HHAs) frequently care for adults with heart failure (HF), but many lack HF training, confidence with HF caregiving, and cannot reach their nurse supervisors by telephone when they need guidance. This may have negative consequences for HHAs and patients.ObjectiveTo examine the effectiveness of an education- and communication-based intervention among HHAs caring for patients with HF.Design, Setting, and ParticipantsThis 2-group pilot randomized clinical trial was conducted in partnership with a large home care agency in New York, New York, from May 2022 to May 2024. HHAs caring for a patient with HF participated. Outcomes were ascertained on an intent-to-treat basis at baseline, mid-study (45 days after the training course), and 90 days.InterventionsThe enhanced usual care (EUC) group received HF training, and the intervention group received HF training plus a mobile health application that allowed HHAs to message nurses.Main Outcomes and MeasuresCo-primary outcomes were HF knowledge (assessed using the Dutch HF Knowledge Scale [DHFKS]; range 0-15; higher score indicates greater knowledge) and HF caregiver self-efficacy (assessed using the Caregiver Contribution to Self-Care in HF Index; range, 0-100; higher score indicates greater efficacy). The secondary outcome was self-reported preventable 911 calls. Exploratory outcomes included patient emergency department (ED) visits and hospitalizations. Mixed-effects models were used to compare trajectories of outcomes between and within study groups.ResultsA total of 102 HHAs (mean [SD] age, 54 [10.5] years; 98 [96.1%] female) were assessed, including 50 in the EUC group and 52 in the intervention group. Overall, 62 HHAs (62.0%) were Black, 1 HHA (1.0%) was American Indian or Alaska Native, 7 HHAs (7.0%) were Asian, 9 HHAs (9.0%) were White, and 21 HHAs (21.0%) identified as other race; 27 HHAs (27.0%) were Hispanic. Within the intervention group, DHFKS scores improved at 90 days, from a median (IQR) score of 6.1 (5.5-6.7) points at baseline to 7.7 (7.0-8.4) points at 90 days (P = .02); however the change did not differ between groups. Across both groups, HHAs with the lowest baseline DHFKS and self-efficacy had the greatest increases at 90 days (median [IQR] change: DHFKS, 1.45 [0.84-2.04] points; self-efficacy, 8.06 [4.42-11.71] points). At 90 days, there were no statistically significant within-group differences in the proportion of HHAs reporting preventable 911 calls group (intervention: 0.51 [95% CI, 0.37-0.64] at baseline vs. 0.34 [95% CI, 0.2-0.49] at 90 days; P = .06; EUC: 0.42 [95% CI, 0.28-0.56] at baseline vs 0.54 [95% CI, 0.38-0.70] at 90 days; P = .21), but the difference between groups was statistically significant (P = .04). This pilot study was not powered for patient-level outcomes, so the risk of ED visits for patients of intervention HHAs (incidence rate ratio, 0.56 [95% CI, 0.25-1.28]; P = .17) should be considered exploratory.Conclusions and RelevanceIn this randomized clinical trial of HHAs caring for patients with HF, HF training improved HHAs' knowledge and self-efficacy, with greatest gains among those with the lowest baseline scores. The ability to message nurses was associated with fewer preventable 911 calls among HHAs in the intervention group. These findings can inform the design of a large-scale trial to better support and integrate HHAs providing HF care.Trial RegistrationClinicalTrials.gov Identifier: NCT04239911

BACKGROUND & AIMS: Hepatic encephalopathy (HE) is a common complication following transjugular intrahepatic portosystemic shunt (TIPS) insertion. However, the prognostic significance of overt HE post-TIPS remains controversial. METHODS: We screened 2137 patients who underwent TIPS insertion at 8 German tertiary care centers between 2004 and 2021. Patients with pre-emptive TIPS placement, hepatocellular carcinoma, missing data, and non-PTFE covered stents were excluded. Competing risk analysis was performed, considering liver transplantation as a competing event. To correct for immortal time bias, landmark analyses were conducted, with the landmark being set at 30 and 90 days post-TIPS. Outcome data were assessed for up to 30 months post-TIPS insertion. RESULTS: A total of 1356 patients (median Model for End-stage Liver Disease [MELD], 13 [interquartile range (IQR), 10-17]; age, 60 years [IQR, 54-67 years]; 64% male; 12% HE before TIPS), were included. Overall, HE post-TIPS was linked to impaired survival (P < .001; subdistribution hazard ratio [sHR], 1.41; 95% confidence interval [CI],1.15-1.73). However, this was only confirmed if HE occurred within the first 30 days post-TIPS (early HE; P < .001; sHR, 2.02; 95% CI, 1.59-2.57). Additionally, patients with a history of HE (P < .001; sHR, 1.59; 95% CI, 1.21-2.07) and history of HE and early HE post-TIPS (P < .001; sHR, 3.44; 95% CI, 2.34-5.04) showed impaired survival. These findings were confirmed in the landmark and multivariable analyses. CONCLUSIONS: Early HE post-TIPS is associated with significantly reduced survival. Therefore, patients who experience early HE or have a history of HE should be closely monitored by physicians, as they constitute a particularly vulnerable group with impaired survival.

Solute carriers (SLCs) regulate cellular and organismal metabolism by transporting small molecules and ions across membranes, yet the physiological substrates of similar to 20% remain elusive. To address this, we developed a machine-learning platform to predict gene-metabolite associations. This approach identifies UNC93A and SLC45A4 as candidate plasma membrane transporters for acetylglucosamine and polyamines, respectively. Additionally, we uncover SLC25A45 as a mitochondrial transporter linked to serum levels of methylated basic amino acids, products of protein catabolism. Mechanistically, SLC25A45 is necessary for the mitochondrial import of methylated basic amino acids, including ADMA and TML, the latter serving as a precursor for carnitine synthesis. In line with this observation, SLC25A45 loss impairs carnitine synthesis and blunts upregulation of carnitine-containing metabolites under fasted conditions. By facilitating mitochondrial TML import, SLC25A45 connects protein catabolism to carnitine production, sustaining beta-oxidation during fasting. Altogether, our study identifies putative substrates for three SLCs and provides a resource for transporter deorphanization.

The receptor-binding domain (RBD) of the SARS-CoV-2 spike (S) protein continues to evolve, facilitating antibody evasion. It remains unclear whether any conserved RBD epitopes persist across SARS-CoV-2 variants and whether vaccination and/or breakthrough infection (BTI) can elicit antibodies capable of targeting these conserved regions to counter future variants. Here, using a heterogeneous double-bait single B-cell sorting strategy, we identify a subset of antibodies with broad-spectrum RBD binding, including recognition of SARS-CoV-1 and emerging variants such as EG.5.1, BA.2.86, JN.1, and KP.2/3. These broadly binding antibodies (bbAbs) exhibit elevated levels of somatic hypermutation but are infrequently derived from clonally expanded B lymphocytes. Passive transfer of representative bbAbs reduces viral infection in a male hamster model. Structural analyses reveals that these bbAbs primarily target three distinct, highly conserved RBD epitopes, suggesting potential regions of future mutational pressure and highlighting the presence of conserved and immunogenic RBD conformations that may serve as a foundation for the development of broadly protective vaccines.

Membrane protein homo-oligomers named higher-order transient structures (HOTS) are formed through cohesive self-interactions in the range of a few kBT. The small magnitude of these interactions underlies the rapid reversibility of HOTS on the timescale of membrane signaling processes, permitting the dynamic modulation of signals. At the same time, weak interactions present an apparent paradox: HOTS should form only if the concentration of a particular protein is sufficiently high to produce oligomerization by mass action. And yet, HOTS are observed experimentally with membrane proteins present in cell membranes at concentrations of only a few per mu m2. In this study, we employ principles of statistical thermodynamics to explain how cells can alter the configurational entropy of the oligomerization reaction, thereby achieving HOTS formation at low concentrations of the protein in the membrane. We propose that this modification of the configurational entropy, a process we call configurational length scaling, is an important aspect of HOTS formation in cell membranes and possibly other cellular compartments.