A Novel Lithium Ion-Assisted TPP Approach for Enhanced Target Discovery

Traditional
thermal proteome profiling (TPP) suffers from limitations
in detecting membrane and weakly bound proteins, potentially overlooking
up to 20% of drug targets. To overcome this, we developed a lithium
ion-assisted TPP (Li-TPP) method that significantly enhances protein
thermal stability detection. Li-TPP successfully captured thermal
shifts in weakly bound proteins like lactate dehydrogenase A (LDHA)
and resolved changes within NMDA receptor complexes. Compared to traditional
TPP, Li-TPP identified 718 additional proteins (R2 >
0.8,
min_slope ≤ −0.06) and significantly increased thermal
displacement values (ΔTm ≥ 1.5 °C) in 368 coidentified
proteins. Importantly, Li-TPP identified known mania-associated targets
like GSK3β as well as novel regulatory proteins such as CRMP2.
Functional enrichment analysis revealed that Li-TPP-identified proteins
were significantly enriched in pathways critical to bipolar disorder,
including microtubule dynamics (MT3 complex), synaptic plasticity
(NMDA receptor assemblies), and energy metabolism (ATP-binding proteins).
This provides mechanistic insights into lithium’s therapeutic
action, highlighting its role in stabilizing neuronal energy homeostasis
and microtubule architecture. This study demonstrates Li-TPP’s
superior performance in detecting challenging protein targets and
provides a powerful new platform for elucidating drug mechanisms and
accelerating the development of multitarget therapeutics for bipolar
disorder.