Visualizing the transdermal delivery of berberine loaded within chitosan microneedles using mass spectrometry imaging.

Berberine (BR), an alkaloid isolated from the Chinese traditional medicine Coptidis rhizoma, exhibits therapeutic effects on several diseases including bacterial infections, diabetes, and hyperlipidemia, but the oral availability is poor. In this work, we prepared the chitosan microneedle array-loaded BR (BR-CS MNAs) to transdermally deliver BR, and the spatial distribution of BR in heterogeneous skin tissues was analyzed and imaged by matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). Some endogenous phospholipids with specific spatial distribution were used to differentiate the epidermis and dermis regions of the skin. The results showed that BR was effectively delivered and could permeate to both epidermis and dermis regions of the skin. This demonstrated the feasibility of MALDI-MSI to evaluate the transdermal delivery efficiency of microneedle arrays and suggested BR could be transdermally delivered by CS MNAs.

Spatial Metabolomics Profiling Reveals Curcumin Induces Metabolic Reprogramming in Three-Dimensional Tumor Spheroids.

Curcumin is widely recognized for its diverse antitumor properties, ranging from breast cancer to many other types of cancers. However, its role in the tumor microenvironment remains to be elucidated. In this study, we established a 3D tumor spheroids model that can simulate the growth environment of tumor cells and visualized the antitumor metabolic alteration caused by curcumin using mass spectrometry imaging technology. Our results showed that curcumin not only exerts a profound impact on the growth and proliferation of breast cancer cells but in situ multivariate statistical analysis also reveals the significant effect on the overall metabolic profile of tumor spheroids. Meanwhile, our visualization map characterized curcumin metabolic processes of reduction and glucuronidation in tumor spheroids. More importantly, abnormal metabolic pathways related to lipid metabolism and polyamine metabolism were also remodeled at the metabolite and gene levels after curcumin intervention. These insights deepen our comprehension of the regulatory mechanism of curcumin on the tumor metabolic network, furnishing powerful references for antitumor treatment.

Stabilization mechanisms and digestion properties of Pickering emulsions prepared with tempo-oxidized hyaluronic acid/chitosan nanoparticles: From the perspective of oxidation degree.

In this study, the stabilization mechanism and digestion behavior of Pickering emulsion prepared by a combination of chitosan (CS) and TEMPO-oxidized hyaluronic acid (HA) were investigated. Conductometric titration was used to determine the degree of oxidation and carboxylate content of TEMPO-oxidized HA. The results showed that the degree of oxidation increased proportionally with increasing oxidation time, and the electrostatic and hydrogen bonding interactions with CS were significantly enhanced. The results of FTIR and TEM showed the formation of CS/oxidized HA nanoparticles (CS/oxidized-HANPs). In addition, the contact angle of CS/oxidized-HANPs is closed to 77°, thereby providing higher desorption energy at the interface. Rheological results showed that the Pickering emulsion exhibited a gel-like network structure and higher viscosity. In vitro digestion results suggested that the quercetin (Que) bioaccessibility of the CS/oxidation HANps-stabilized Pickering emulsion with an oxidation time of 20 min was better than that of the conventional emulsion prepared with CS alone. The research is expected to develop novel polysaccharide-based Pickering emulsion delivery systems for functional compounds.

Integrated spatial metabolomics and transcriptomics decipher the hepatoprotection mechanisms of wedelolactone and demethylwedelolactone on non-alcoholic fatty liver disease.

Eclipta prostrata L. has been used in traditional medicine and known for its liver-protective properties for centuries. Wedelolactone (WEL) and demethylwedelolactone (DWEL) are the major coumarins found in E. prostrata L. However, the comprehensive characterization of these two compounds on non-alcoholic fatty liver disease (NAFLD) still remains to be explored. Utilizing a well-established zebrafish model of thioacetamide (TAA)-induced liver injury, the present study sought to investigate the impacts and mechanisms of WEL and DWEL on NAFLD through integrative spatial metabolomics with liver-specific transcriptomics analysis. Our results showed that WEL and DWEL significantly improved liver function and reduced the accumulation of fat in the liver. The biodistributions and metabolism of these two compounds in whole-body zebrafish were successfully mapped, and the discriminatory endogenous metabolites reversely regulated by WEL and DWEL treatments were also characterized. Based on spatial metabolomics and transcriptomics, we identified that steroid biosynthesis and fatty acid metabolism are mainly involved in the hepatoprotective effects of WEL instead of DWEL. Our study unveils the distinct mechanism of WEL and DWEL in ameliorating NAFLD, and presents a "multi-omics" platform of spatial metabolomics and liver-specific transcriptomics to develop highly effective compounds for further improved therapy.

Mass spectrometry imaging-based metabolomics highlights spatial metabolic alterations in three types of liver injuries.

Liver's distinctive function renders it highly susceptible to diverse damage sources. Characterizing the metabolic profiles and spatial signatures in different liver injuries is imperative for early diagnosis and etiology-oriented treatment. In this comparative study, we conducted whole-body spatial metabolomics on zebrafish with liver injury induced by ethanol (EtOH), acetaminophen (APAP), and thioacetamide (TAA). The two specific levels, the whole-body and liver-specific metabolic profiles, as well as their regional distributions, were systematically mapped in situ by mass spectrometry imaging, which is distinct from conventional LC-MS and GC-MS methods. We found that liver injury regions exhibited more pronounced metabolic reprogramming than the entire organism, leading to significant alterations in eight fatty acids, three phospholipids, and four low-molecular-weight metabolites. More importantly, fatty acids as well as small molecule metabolites including glutamine, glutamate, taurine and malic acid displayed contrasting changes between alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD). In addition, phospholipids, including Lyso PC (16:0) and Lyso PE (18:0), demonstrated notable down-regulation in all damaged liver, whereas PC (34:1) underwent upregulation. This study not only deepens insights into distinct potential biomarkers for liver injuries, but also underscores spatial metabolomics as a powerful tool to elucidate possible pathogenic mechanisms in other metabolic diseases.

Isotope-Coded On-Tissue Derivatization for Quantitative Mass Spectrometry Imaging of Short-Chain Fatty Acids in Biological Tissues.

Short-chain fatty acids (SCFAs), as the main metabolites of gut microbiota, are recognized as crucial players in the host's inflammatory response and metabolic disease. Imaging the spatial distributions and calculating the accurate contents of SCFAs in the heterogeneous intestinal tissue are critical to reveal their biological functions. Here, we develop an isotope-coded on-tissue derivatization method combined with matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to map the spatial expressions of SCFAs in the colon tissue based on pair-labeled N,N,N-trimethyl-2-(piperazin-1-yl)ethan-1-aminium iodide (TMPA) and D3-TMPA. A noticeable increase in the MALDI-MSI sensitivity of SCFAs was achieved after on-tissue derivatization, which enables the visualization of acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, hydroxy acetic acid, and hydroxy propionic acid in the colon tissue. Moreover, the introduction of D3-TMPA-tagged SCFAs as internal standards can significantly reduce quantitation deviation from the matrix effects, ensuring the quantitative MALDI-MSI of SCFAs. We further used this method to characterize the spatial alterations of SCFAs in the colon tissues of mice with enterocolitis. The development of this strategy provides a reliable approach to image the spatial expressions of SCFAs in tissues and paves an insight way to study the roles of SCFAs in the gut microbiota and disease.

In-depth profiling of carbohydrate isomers in biological tissues by chemical derivatization-assisted mass spectrometry imaging.

Carbohydrates play crucial regulatory roles in various physiological and pathological processes. However, the low ionization efficiency and the presence of linkage pattern, monosaccharide composition and anomeric configuration isomers make their in-depth analysis very challenging, especially for heterogeneous biological tissues. In this study, we propose a high-sensitive and isomer-specific imaging approach to visualize the spatial distributions of monosaccharide and disaccharide isomers by integrating chemical derivatization and matrix-assisted laser desorption/ionization tandem mass spectrometry imaging (MALDI-MS2I). 2-Pyridinecarbohydrazide (PYD) is developed as a novel derivatization reagent which can not only improves the MS sensitivity of carbohydrates, but also enables the identification and visualization of ketose and aldose monosaccharide isomers, as well as linkage pattern, monosaccharide composition and anomeric configuration disaccharide isomers by mass spectrometry imaging of isomer-specific MS/MS fragment ions. Moreover, we build quantitative MALDI-MS2 and MALDI-MS2I methods for disaccharide isomers based on the diagnostic fragment ions, and good linear relationships could be achieved both in solution and on glass slides. We expect that this study should provide new ideas for in-depth profiling of the spatial signatures of carbohydrates in biological tissues and lay the foundation for a deeper understanding of carbohydrates' structure.

Enzyme-assisted Aqueous Extraction of Oil from Rice Germ and its Physicochemical Properties and Antioxidant Activity.

Enzyme-assisted aqueous extraction of rice germ oil (RGO) was performed in this study. The physicochemical properties, fatty acid composition, bioactive substances and antioxidant activity of RGO were analyzed. An enzyme composed of alcalase and cellulase (1:1, w/w) was found to be the most effective in the extraction yield of oil. The optimal oil yield of 22.27% was achieved under the conditions of an enzyme concentration of 2% (w/w), incubation time of 5 h, incubation temperature of 50°C, water to seed ratio of 5:1, and pH 6.0. The predominant fatty acids of RGO were oleic acid (39.60%), linoleic acid (34.20%) and palmitic acid (20.10%). The total saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA) composition of RGO were 22.50%, 39.60% and 36.00%, respectively. RGO yielded a high content of γ-oryzanol (530 mg/100 g oil), tocotrienol (62.96 mg/100 g oil), tocopherol (23.24 mg/100 g oil) and a significant amount of phytosterol (372.14 mg/100 g oil). It exhibited notable antioxidant activities with IC50 values of 32.37 and 41.13 mg/mL, according to the DPPH radical scavenging assay and ß-carotene/linoleic acid bleaching test, respectively.