Time-Resolved Ultraviolet Photodissociation Mass Spectrometry Probes the Mutation-Induced Alterations in Protein Stability and Unfolding Dynamics.

How mutations impact protein stability and structure dynamics is crucial for understanding the pathological process and rational drug design. Herein, we establish a time-resolved native mass spectrometry (TR-nMS) platform via a rapid-mixing capillary apparatus for monitoring the acid-initiated protein unfolding process. The molecular details in protein structure unfolding are further profiled by a 193 nm ultraviolet photodissociation (UVPD) analysis of the structure-informative photofragments. Compared with the wild-type dihydrofolate reductase (WT-DHFR), the M42T/H114R mutant (MT-DHFR) exhibits a significant stability decrease in TR-nMS characterization. UVPD comparisons of the unfolding intermediates and original DHFR forms indicate the special stabilization effect of cofactor NADPH on DHFR structure, and the M42T/H114R mutations lead to a significant decrease in NADPH-DHFR interactions, thus promoting the structure unfolding. Our study paves the way for probing the mutation-induced subtle changes in the stability and structure dynamics of drug targets.

Panda-UV Unlocks Deeper Protein Characterization with Internal Fragments in Ultraviolet Photodissociation Mass Spectrometry.

Ultraviolet photodissociation (UVPD) mass spectrometry unlocks insights into the protein structure and sequence through fragmentation patterns. While N- and C-terminal fragments are traditionally relied upon, this work highlights the critical role of internal fragments in achieving near-complete sequencing of protein. Previous limitations of internal fragment utilization, owing to their abundance and potential for random matching, are addressed here with the development of Panda-UV, a novel software tool combining spectral calibration, and Pearson correlation coefficient scoring for confident fragment assignment. Panda-UV showcases its power through comprehensive benchmarks on three model proteins. The inclusion of internal fragments boosts identified fragment numbers by 26% and enhances average protein sequence coverage to a remarkable 93% for intact proteins, unlocking the hidden region of the largest protein carbonic anhydrase II in model proteins. Notably, an average of 65% of internal fragments can be identified in multiple replicates, demonstrating the high confidence of the fragments Panda-UV provided. Finally, the sequence coverages of mAb subunits can be increased up to 86% and the complementary determining regions (CDRs) are nearly completely sequenced in a single experiment. The source codes of Panda-UV are available at https://github.com/PHOENIXcenter/Panda-UV.

Ultrasound-guided caudal anaesthesia combined with epidural anaesthesia for caesarean section: a randomized controlled clinical trial.

BACKGROUND: Although epidural anaesthesia and spinal anaesthesia are currently the general choices for patients undergoing caesarean section, these two neuraxial anaesthesia methods still have drawbacks. Caudal anaesthesia has been considered to be more appropriate for gynaecological surgery. The purpose of this study was to compare epidural anaesthesia combined with caudal anaesthesia, spinal anaesthesia and single-space epidural anaesthesia for caesarean section with respect to postoperative comfort and intraoperative anaesthesia quality. METHODS: In this clinical trial, 150 patients undergoing elective caesarean section were recruited and randomized into three groups according to a ratio of 1:1:1to receive epidural anaesthesia only, spinal anaesthesia only or epidural anaesthesia combined with caudal anaesthesia. The primary outcome was postoperative comfort in the three groups. Secondary outcomes included intraoperative anaesthesia quality and the incidences of nausea, vomiting, postdural puncture headache, maternal bradycardia, or hypotension. RESULTS: More patients were satisfied with the intraoperative anaesthesia quality in the EAC group than in the EA group (P = 0.001). The obstetrician was more significantly satisfied with the intraoperative anaesthesia quality in the SA and EAC groups than in the EA group (P = 0.004 and 0.020, respectively). The parturients felt more comfortable after surgery in the EA and EAC groups (P = 0.007). The incidence of maternal hypotension during caesarean section was higher in the SA group than in the EA and EAC groups (P = 0.001 and 0.019, respectively). CONCLUSIONS: Epidural anaesthesia combined with caudal anaesthesia may be a better choice for elective caesarean section. Compared with epidural anaesthesia and spinal anaesthesia, it has a higher quality of postoperative comfort and intraoperative anaesthesia.

Effects of dexmedetomidine combined with etomidate on postoperative cognitive function in older patients undergoing total intravenous anaesthesia: a randomized, double-blind, controlled trial.

BACKGROUND: Etomidate has been advocated for anesthesia in older and critically ill patients because of its hemodynamic stability. Clinical studies have shown that dexmedetomidine has neuroprotective and anti-inflammatory properties and improves postoperative cognitive dysfunction in older patients. The present study was to evaluate the effects of the combination of etomidate and dexmedetomidine with different anaesthesia time on postoperative cognitive function in older patients. METHODS: A total of 132 older patients undergoing ureteroscopic holmium laser lithotripsy were randomly divided into EN group and ED group equally. Patients whose surgery time was less than or equal to 1 h in each group were allocated to short-time surgery group (EN1 group and ED1 group), and whose surgery time was more than 1h were allocated to long-term surgery group (EN2 group and ED2 group). The primary outcome was the score of the Mini-Mental State Examination. The secondary outcomes were State-Trait Anxiety Inventory scores, Riker sedation agitation scores, Zung Self-Rating Depression Scale scores, the memory span for Arabic numerals, the plasma concentrations of S-100 calcium-binding protein B and neuron specific enolase, the time to spontaneous respiration, recovery, and extubation. RESULTS: The MMSE scores at t2-3 were higher in ED1 and ED2 groups than in EN1 and EN2 groups (p<0.05). Compared with ED1 and ED2 groups, the ZSDS scores, the S-AI scores and the T-AI scores at t1-2 were higher in EN1 and EN2 groups (p<0.05), respectively. The recalled Arabic numbers at t1-3 were higher in ED2 group than in EN2 group (p<0.05). The plasma concentration of S-100ß at t1-2 in EN1 group and t1-3 in EN2 group were higher than that in ED1 and ED2 groups (p<0.05), respectively. Compared with ED1 and ED2 groups, the plasma concentrations of NSE were higher at t1-3 in EN1 group and t1-4 in EN2 group (p<0.05), respectively. CONCLUSION: The administration of dexmedetomidine could improve postoperative cognitive dysfunction, emergence agitation, depression and anxiety, attenuate the plasma concentrations of S-100ß and NSE in older patients undergoing total intravenous anaesthesia with etomidate. TRIAL REGISTRATION: Registration number: ChiCTR1800015421, Date: 29/03/2018.

The utility of proteases in proteomics, from sequence profiling to structure and function analysis.

In mass spectrometry (MS)-based bottom-up proteomics, protease digestion plays an essential role in profiling both proteome sequences and post-translational modifications (PTMs). Trypsin is the gold standard in digesting intact proteins into small-size peptides, which are more suitable for high-performance liquid chromatography (HPLC) separation and tandem MS (MS/MS) characterization. However, protein sequences lacking Lys and Arg cannot be cleaved by trypsin and may be missed in conventional proteomic analysis. Proteases with cleavage sites complementary to trypsin are widely applied in proteomic analysis to greatly improve the coverage of proteome sequences and PTM sites. In this review, we survey the common and newly emerging proteases used in proteomics analysis mainly in the last 5 years, focusing on their unique cleavage features and specific proteomics applications such as missing protein characterization, new PTM discovery, and de novo sequencing. In addition, we summarize the applications of proteases in structural proteomics and protein function analysis in recent years. Finally, we discuss the future development directions of new proteases and applications in proteomics.

Ultraviolet Photodissociation Reveals the Molecular Mechanism of Crown Ether Microsolvation Effect on the Gas-Phase Native-like Protein Structure.

Maintaining the protein high-order structures and interactions during the transition from aqueous solution to gas phase is essential to the structural analysis of native mass spectrometry (nMS). Herein, we systematically interrogate the effects of charge state and crown ether (CE) complexation on the gas-phase native-like protein structure by integrating nMS with 193 nm ultraviolet photodissociation (UVPD). The alterations of photofragmentation yields of protein residues and the charge site distribution of fragment ions reveal the specific sites and sequence regions where charge and CE take effect. Our results exhibit the CE complexation on protonated residues can largely alleviate the structure disruption induced by the intramolecular solvation of charged side chains. The influences of CE complexation and positive charge on gas-phase protein structure exhibit generally opposite trends because the CE microsolvation avoids the hydrogen-bonding formation between the charged side chains with backbone carbonyls. Thus, CE complexation leads to a more stable and native-like protein structure in the gas phase.

Structural Mass Spectrometry Probes the Inhibitor-Induced Allosteric Activation of CDK12/CDK13-Cyclin K Dissociation.

The rational design and development of effective inhibitors for cyclin-dependent kinases 12 and 13 (CDK12 and CDK13) are largely dependent on the understanding of the dynamic inhibition conformations but are difficult to be achieved by conventional characterization tools. Herein, we integrate the structural mass spectrometry (MS) methods of lysine reactivity profiling (LRP) and native MS (nMS) to systematically interrogate both the dynamic molecular interactions and overall protein assembly of CDK12/CDK13-cyclin K (CycK) complexes under the modulation of small molecule inhibitors. The essential structure insights, including inhibitor binding pocket, binding strength, interfacial molecular details, and dynamic conformation changes, can be derived from the complementary results of LRP and nMS. We find the inhibitor SR-4835 binding can greatly destabilize the CDK12/CDK13-CycK interactions in an unusual allosteric activation way, thereby providing a novel alternative for the kinase activity inhibition. Our results underscore the great potential of LRP combination with nMS for the evaluation and rational design of effective kinase inhibitors at the molecular level.

Molecular Structure Characterization of Micro/Nanoplastics by 193 nm Ultraviolet Photodissociation Mass Spectrometry.

The degradation of macroplastics results in micro/nanoplastics (MNPs) in the natural environment, inducing high health risks worldwide. It remains challenging to characterize the accurate molecular structures of MNPs. Herein, we integrate 193 nm ultraviolet photodissociation (UVPD) with mass spectrometry to interrogate the molecular structures of poly(ethylene glycol) terephthalate and polyamide (PA) MNPs. The backbones of the MNP polymer can be efficiently dissociated by UVPD, producing rich types of fragment ions. Compared to high-energy collision dissociation (HCD), the structural informative fragment ions and corresponding sequence coverages obtained by UVPD were all improved 2.3 times on average, resulting in almost complete sequence coverage and precise structural interrogation of MNPs. We successfully determine the backbone connectivity differences of MNP analogues PA6, PA66, and PA610 by improving the average sequence coverage from 26.8% by HCD to 89.4% by UVPD. Our results highlight the potential of UVPD in characterizing and discriminating backbone connectivity and chain end structures of different types of MNPs.

Radiation-free endoscopic papillectomy for ampullary adenoma: experience from a Chinese tertiary hospital.

BACKGROUND: Conventional endoscopic papillectomy (ESP) for ampullary adenoma is performed as a hybrid endoscopy and fluoroscopy guided procedure. In this study, we report our preliminary experience of non-radiation ESP. METHODS: The present method includes endoscopic snare resection, non-radiation endoscopic biliary and pancreatic stenting and endoclipping. Data from ten patients who underwent non-radiation ESP due to ampullary adenoma were collected. Procedure details, adverse events and follow-up were analyzed. RESULTS: Complete resection was accomplished in all patients, with en bloc resection and piecemeal resection in nine and one patient(s), respectively. Both biliary and pancreatic stenting and biliary stenting alone were achieved in eight and two patients, respectively. Endoclipping was performed in all patients. Hyperleukocytosis and hyperamylasemia occurred in two and one patient(s), respectively. No other complications occurred. No lesion residual or recurrence occurred during follow-up. CONCLUSIONS: Radiation-free ESP can be technically feasible and safely executed by experienced endoscopists. Our study provides a novel strategy for endoscopic resection of major papilla adenoma.

Effects of spinal anaesthesia and intravenous general anaesthesia on the absorption of normal salinein patients undergoing hysteroscopic endometrial resection: an observational study.

INTRODUCTION: The absorption of uterine distention fluid during hysteroscopic endometrial resection can cause volumeoverload, which can lead to coagulation dysfunction, acute left heart failure and pulmonary oedema in patients. The effects of spinal anaesthesia and intravenous general anaesthesia on the absorption of normal saline as uterine distention fluid during hysteroscopic surgery remain unclear. The aim of this clinical trial was toobserve the effects of spinal anaesthesia and intravenous general anaesthesia on the absorption of normal saline in patients undergoing hysteroscopic endometrial resection. METHODS: A total of 126 patients undergoing elective hysteroscopic endometrial resection were divided into a spinal anaesthesia group (s group) and a propofol-fentanyl intravenous anaesthesia group (PF group), with 63 cases in each group, and both groups were divided into a short-term group (S1 group and PF1 group) and a long-term group (S2 group and PF2 group) according to the operation time. The primary outcome was the absorption of normal saline, and the secondary outcomes included the perioperative SBP, DBP, HR and SpO2 and postoperative haematocrit values, and the incidence of postoperative complications. RESULTS: The volume of saline absorbed was significantly increased in the S2 and PF2 groups compared with the S1 and PF1 groups (P < 0.001). There was a significant positive correlation between the amount of normal saline absorbed and the operation time (r = 0.895, P < 0.001). The postoperative haematocrit value was slightly lower than that before the operation in all four groups (P < 0.05), and there were no differences in the incidences of urinary retention, sinus bradycardia or hypotension between groups (P > 0.05). CONCLUSIONS: There was no difference in the effects of spinal anaesthesia and intravenous general anaesthesia on the absorption of normal saline during hysteroscopic endometrial resection, and the absorption of normal saline increased accordingly with the extension of operation time.

Renal transporter OAT1 and PPAR-α pathway co-contribute to icaritin-induced nephrotoxicity.

This study aimed to investigate the potential nephrotoxicity of icaritin and the underlying mechanism by in vitro-in vivo experiment technology combined with proteomics technology. First, icaritin showed a significant cytotoxic effect on HK-2 cells, which was accompanied by increased LDH and TNF-α in the supernatant, decreased protein expressions of Bcl-2 and increased Bax and enhanced apoptosis of HK-2 cells as measured by TUNEL staining. Moreover, icaritin induced obvious tubular damage and up-regulation of BUN and CRE levels in plasma in mice. Second, intracellular uptake of icaritin was considerably higher in hOAT1-HEK293 cells than in mock-HEK293 cells, suggesting that icaritin might accumulate in renal cells via OAT1 uptake. Importantly, icaritin caused significant changes in the PPAR signaling pathway in HK2 cells through proteomic analysis. Then, in vitro and in vivo results verified that icaritin significantly downregulated the protein expression of PPAR-α as well as downregulated APOB, ACSL3, ACSL4, and upregulated 5/12/15-HETE, implying that a lipid metabolism disorder was involved in the icaritin-induced nephrotoxicity. Finally, icaritin was found to increase the accumulation of iron and LPO levels while reducing the activity of GPX4, suggesting that ferroptosis was involved in the nephrotoxicity induced by icaritin.

Chloride-Mediated Peroxide-Free Photochemical Oxidation of Proteins (PPOP) in Mass Spectrometry-Based Structural Analysis.

Ultraviolet (UV) laser photolysis of hydrogen peroxide (H2O2) for the in situ generation of hydroxyl radicals (•OH) is a widely utilized strategy in the oxidation footprinting of native proteins and mass spectrometry (MS)-based structural analysis. However, it remains challenging to realize peroxide-free photochemical oxidation footprinting. Herein, we describe the footprinting of native proteins by chloride-mediated peroxide-free photochemical oxidation of proteins (PPOP). The protein samples are prepared within biocompatible phosphate-buffered saline (PBS) containing 10 mM Gln as radical scavengers and oxidized in a capillary flow reactor directly under a single-pulse (10 ns) irradiation of a 193 nm ArF UV laser. The main oxidized protein residues are CMYWFHLI. We demonstrate that the PPOP-MS strategy is highly sensitive to the protein high-order structures and can be applied to monitor the protein-drug interfaces, which provides a promising footprinting alternative for protein structure-function explorations.

The interfacial interactions of nanomaterials with human serum albumin.

The fates of nanomaterials (NMs) in vivo are greatly dependent on their interactions with human serum proteins. However, the interfacial molecular details of NMs-serum proteins are still difficult to be probed. Herein, the molecular interaction details of human serum albumin (HSA) with Au and SiO2 nanoparticles have been systematically interrogated and compared by using lysine reactivity profiling mass spectrometry (LRP-MS). We demonstrated the biocompatibility of Au is better than SiO2 nanoparticles and the NMs surface charge state played a more important role than particle size in the combination of NMs-HSA at least in the range of 15-40 nm. Our results will contribute to the fundamental mechanism understanding of NMs-serum protein interactions as well as the NMs rational design.

Coronas of micro/nano plastics: a key determinant in their risk assessments.

As an emerging pollutant in the life cycle of plastic products, micro/nanoplastics (M/NPs) are increasingly being released into the natural environment. Substantial concerns have been raised regarding the environmental and health impacts of M/NPs. Although diverse M/NPs have been detected in natural environment, most of them display two similar features, i.e.,high surface area and strong binding affinity, which enable extensive interactions between M/NPs and surrounding substances. This results in the formation of coronas, including eco-coronas and bio-coronas, on the plastic surface in different media. In real exposure scenarios, corona formation on M/NPs is inevitable and often displays variable and complex structures. The surface coronas have been found to impact the transportation, uptake, distribution, biotransformation and toxicity of particulates. Different from conventional toxins, packages on M/NPs rather than bare particles are more dangerous. We, therefore, recommend seriously consideration of the role of surface coronas in safety assessments. This review summarizes recent progress on the eco-coronas and bio-coronas of M/NPs, and further discusses the analytical methods to interpret corona structures, highlights the impacts of the corona on toxicity and provides future perspectives.

Size-Selective VAILase Proteolysis Provides Dynamic Insights into Protein Structures.

Monitoring the dynamic alterations of protein structures within an aqueous solution remains enormously challenging. In this study, we describe a size-selective VAILase proteolysis (SVP)-mass spectrometry (MS) strategy to probe the protein structure changes without strict control of the proteolysis kinetics. The unique conformation selectivity of SVP depends on the uniform nano-sized entrance pores of the VAILase hexameric cage as well as the six inherent molecular rulers in the VAILase-substrate recognition and cleavage. The dynamic insights into subtle conformation alterations of both myoglobin unfolding transition and Aurora kinase A-inhibitor binding are successfully captured using the SVP strategy, which matches well with the results in the molecular dynamics simulation. Our work provides a new paradigm of size-selective native proteolysis for exploring the aqueous protein structure-function relationships.

Lysine reactivity profiling reveals molecular insights into human serum albumin-small-molecule drug interactions.

Human serum albumin (HSA) is one of the most important serum carrier proteins that deliver small-molecule drugs to their specific targets. Clarifying the molecular mechanism of the interaction between natural HSA and drugs in an aqueous solution has been a hot topic in pharmaceutical chemistry, clinical medicine, and biochemistry in recent years, but it is still challenging. In this paper, the details of molecular interactions of HSA with a variety of therapeutic drugs including ibuprofen, indomethacin, phenylbutazone, and warfarin are systematically investigated using a mass spectrometry (MS)-based lysine reactivity profiling (LRP) strategy. The results reaffirm that the major ligand binding sites (including Sites I and II) of HSA are located in subdomains IIA and IIIA, while several potential drug-binding areas at subdomain IIIB and α helix IIB-IIIA are newly characterized. The MS-LRP strategy may have important application prospects in pharmacodynamics, pharmacokinetics, and safety evaluation of small-molecule drugs.

A comparison of the Mini-Mental State Examination (MMSE) with the Montreal Cognitive Assessment (MoCA) for mild cognitive impairment screening in Chinese middle-aged and older population: a cross-sectional study.

BACKGROUND: The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) are the most commonly used scales to detect mild cognitive impairment (MCI) in population-based epidemiologic studies. However, their comparison on which is best suited to assess cognition is scarce in samples from multiple regions of China. METHODS: We conducted a cross-sectional analysis of 4923 adults aged ≥55 years from the Community-based Cohort Study on Nervous System Diseases. Objective cognition was assessed by Chinese versions of MMSE and MoCA, and total score and subscores of cognitive domains were calculated for each. Education-specific cutoffs of total score were used to diagnose MCI. Demographic and health-related characteristics were collected by questionnaires. Correlation and agreement for MCI between MMSE and MoCA were analyzed; group differences in cognition were evaluated; and multiple logistic regression model was used to clarify risk factors for MCI. RESULTS: The overall MCI prevalence was 28.6% for MMSE and 36.2% for MoCA. MMSE had good correlation with MoCA (Spearman correlation coefficient = 0.8374, p < 0.0001) and moderate agreement for detecting MCI with Kappa value of 0.5973 (p < 0.0001). Ceiling effect for MCI was less frequent using MoCA versus MMSE according to the distribution of total score. Percentage of relative standard deviation, the measure of inter-individual variance, for MoCA (26.9%) was greater than for MMSE (19.0%) overall (p < 0.0001). Increasing age (MMSE: OR = 2.073 for ≥75 years; MoCA: OR = 1.869 for≥75 years), female (OR = 1.280 for MMSE; OR = 1.163 for MoCA), living in county town (OR = 1.386 and 1.862 for MMSE and MoCA, respectively) or village (OR = 2.579 and 2.721 for MMSE and MoCA, respectively), smoking (OR = 1.373 and 1.288 for MMSE and MoCA, respectively), hypertension (MMSE: OR = 1.278; MoCA: OR = 1.208) and depression (MMSE: OR = 1.465; MoCA: OR = 1.350) were independently associated with greater likelihood of MCI compared to corresponding reference group in both scales (all p < 0.05). CONCLUSIONS: MoCA is a better measure of cognitive function due to lack of ceiling effect and with good detection of cognitive heterogeneity. MCI prevalence is higher using MoCA compared to MMSE. Both tools identify concordantly modifiable factors for MCI, which provide important evidence for establishing intervention measures.

Effects of dexmedetomidine on intraoperative hemodynamics, recovery profile and postoperative pain in patients undergoing laparoscopic cholecystectomy: a randomized controlled trial.

BACKGROUND: To investigate the optimal dose of dexmedetomidine to maintain hemodynamic stability, prevent of cough and minimize postoperative pain for patients undergoing laparoscopic cholecystectomy. METHODS: One hundred twenty patients were randomly divided into D1, D2, D3 and NS groups, and dexmedetomidine 0.4, 0.6, 0.8µg/kg and normal saline were administrated respectively. Patients' heart rate, systolic blood pressure and diastolic blood pressure were measured at T1-T7. The incidence of cough was recorded. Other parameters were noted, the time of spontaneous respiratory recovery and extubation, visual analogue scale scores and dosage of tramadol. RESULTS: The heart rate, systolic blood pressure and diastolic blood pressure of D2 and D3 groups has smaller fluctuations at T2-3 and T7 compared with NS and D1 groups (P < 0.05). The incidence of cough was lower in D2 and D3 groups than NS group (P < 0.05). The visual analogue scale scores and tramadol dosage of D2 and D3 groups were lower than NS group (P < 0.05). The time of spontaneous respiratory recovery and extubation in D3 group was longer than that in D1 and D2 groups (P < 0.05). CONCLUSIONS: Intravenous infusion of 0.6µg/kg dexmedetomidine before induction can maintain hemodynamic stability, decrease cough during emergence, relieve postoperative pain of patients undergoing laparoscopic cholecystectomy. TRIAL REGISTRATION: ChiCTR1900024801 , registered at the Chinese Clinical Trial Registry, principal investigator: Qin Ye, date of registration: July 28, 2019.

Probing the Proteomics Dark Regions by VAILase Cleavage at Aliphatic Amino Acids.

Proteomics emerges from the protein identification to protein functional elucidation, which depends to a large extent on the characterization of protein sequences. However, a large part of proteome sequences remains unannotated due to the limitation in proteolytic digestion by golden standard protease trypsin. Herein, we demonstrated that a cyanobacterial protease VAILase could specifically cleave at the short-chain aliphatic amino acids valine, alanine, leucine, isoleucine and threonine with cleavage specificity about 92% in total for proteomic analysis. The unique features of VAILase cleavage facilitate the characterization of most proteins and exhibit high complementarity to trypsin, and 22% of the covered sequences by VAILase are unique. VAILase can greatly improve the coverages of sequences with abundant aliphatic residues that are usually dark regions in conventional proteomic analysis, such as the transmembrane regions within anion exchanger 1 and photosystem II.

Spatially Resolved Proteome Mapping of Laser Capture Microdissected Tissue with Automated Sample Transfer to Nanodroplets.

Current mass spectrometry (MS)-based proteomics approaches are ineffective for mapping protein expression in tissue sections with high spatial resolution because of the limited overall sensitivity of conventional workflows. Here we report an integrated and automated method to advance spatially resolved proteomics by seamlessly coupling laser capture microdissection (LCM) with a recently developed nanoliter-scale sample preparation system termed nanoPOTS (Nanodroplet Processing in One pot for Trace Samples). The workflow is enabled by prepopulating nanowells with DMSO, which serves as a sacrificial capture liquid for microdissected tissues. The DMSO droplets efficiently collect laser-pressure catapulted LCM tissues as small as 20 µm in diameter with success rates >87%. We also demonstrate that tissue treatment with DMSO can significantly improve proteome coverage, likely due to its ability to dissolve lipids from tissue and enhance protein extraction efficiency. The LCM-nanoPOTS platform was able to identify 180, 695, and 1827 protein groups on average from 12-µm-thick rat brain cortex tissue sections having diameters of 50, 100, and 200 µm, respectively. We also analyzed 100-µm-diameter sections corresponding to 10-18 cells from three different regions of rat brain and comparatively quantified ∼1000 proteins, demonstrating the potential utility for high-resolution spatially resolved mapping of protein expression in tissues.