CP-2

Mitochondrial dysfunction is implicated in Alzheimer's disease (AD), but whether it drives AD‐associated changes is unclear. We assessed transcriptomic alterations in the brains of Ndufs4−/− mice, a model of mitochondrial complex I (mtCI) deficiency, and evaluated the therapeutic effects of the neuroprotective mtCI inhibitor CP2.

Cortico‐hippocampal tissue from Ndufs4−/− and wild‐type mice was subjected to transcriptomic analysis, followed by cross‐species comparisons to human late‐onset AD and familial AD mouse datasets.

Knockout of Ndufs4‐mediated mtCI deficiency disrupted mitochondrial homeostasis, energy metabolism, and synaptic gene expression, recapitulating transcriptomic signatures of AD. CP2 treatment partially reversed these changes, with female Ndufs4−/− mice showing greater compensatory adaptations and treatment responses.

Loss of mtCI activity alone is sufficient to induce AD‐like molecular changes in the brain, independent of amyloid beta or phosphorylated tau. CP2‐mediated rescue highlights the potential of targeting mitochondria as a therapeutic strategy for AD. Sex‐specific responses suggest important considerations for personalized therapeutics.

Activity of mitochondrial complex I (mtCI) affects broad mitochondrial and neuronal transcriptional networks.A reduction of mtCI activity is sufficient to induce transcriptomic changes reminiscent of those observed in late‐onset Alsheimer's disease (AD) patients and familial mouse models of AD.Pharmacological targeting of mtCI mediates neuroprotective signaling.Male and female mice have differential responses to the loss of mtCI activity and to the mitochondria‐targeted therapeutics.Mitochondria play a key role in AD development and treatment.

Objective: To address the unmet clinical need for Lysine (K)-specific demethylase 4A (KDM4A)-targeted therapies in nonsmall cell lung cancer (NSCLC), we developed a novel theranostic pair, ⁶⁸Ga/¹⁶¹Tb-CP2, leveraging the epigenetic regulator KDM4A and terbium-161's high linear energy transfer (LET) Auger electrons for precision therapy. Methods: The radiopharmaceutical was synthesized via a one-step chelation protocol. Radiochemical purity and stability were validated by radio-HPLC and radio-TLC. In vitro studies evaluated the nuclear targeting ability of ¹⁶¹Tb-CP2 by cellular uptake and cellular internalization, and quantified tumor cell proliferation by carboxyfluorescein diacetate, succinimidyl ester immunofluorescence and flow cytometry. In vivo studies used NCI-H2228 xenografts for ⁶⁸Ga-CP2 micro-PET/CT imaging and ¹⁶¹Tb-CP2 micro-SPECT/CT biodistribution analysis. The DNA damage was assessed by γ-H2AX immunohistochemistry. Results: We successfully synthesized a paired diagnostic and therapeutic radiopharmaceutical specifically targeting KDM4A⁶⁸Ga/¹⁶¹Tb-CP2. The preparation protocol is simple, with the radiochemical purity of the radiopharmaceutical exceeding 97%, and the quality control results meet the requirements for stability and specific activity. Cellular uptake and cellular internalization showed that tumor cells were able to efficiently uptake ¹⁶¹Tb-CP2 and transport ¹⁶¹Tb-CP2 into the nucleus to exert its killing effect. ¹⁶¹Tb-CP2 inhibited tumor cell proliferation (mean fluorescence intensity: 100.00 ± 0.35% vs 125.77 ± 1.93%, control vs 48 h group, P < 0.001) at the cellular level. The NCI-H2228-bearing NSCLC model demonstrated high tumor uptake of ⁶⁸Ga-CP2 (SUV_max of 0.26 ± 0.06). Micro-SPECT/CT revealed that ¹⁶¹Tb-CP2 is metabolized mainly through the kidney-bladder pathway, has moderate uptake (0.29 ± 0.01%ID/g at 12 h) and retention rates (0.34 ± 0.01%ID/g at 72 h) in tumors, and has a high target/nontarget ratio (3.4 ± 0.1 at 72 h). Immunohistochemistry confirmed the tumor-killing effect of ¹⁶¹Tb-CP2 and its safety in normal tissues. Conclusions: ⁶⁸Ga/¹⁶¹Tb-CP2 has transformative value for the evaluation and treatment of KDM4A-overexpressing tumors. This KDM4A-targeting radiopharmaceutical provides new directions for tumor research and new ideas for tumor management that use the Auger electron of Tb-161 to target genetic material.