H2S In Cells Research Articles

Chitosan-naphthalimide probes for dual channel recognition of HClO and H2S in cells and their application in photodynamic therapy

The combination of bio-imaging with photodynamic therapy (PDT) to accomplish theranostics is promising in cancer treatment. Three chitosan-naphthalimide probes were studied in this work. 4-(5-Bromothiophen-2-yl)-1,8-naphthalic anhydride was first synthesized, and then reacted with chitosan to obtain the macromolecules (CS-N-Br). The recognition group thiomorpholine or its derivatives were introduced into CS-N-Br to obtain nano-probes (CS-N-ML, CS-N-BSZ, CS-N-FSQ) eventually. The studies revealed that CS-N-ML and CS-N-FSQ exhibit high selectivity and can specifically recognize HClO and H2S. CS-N-ML and CS-N-FSQ can perform exogenous and endogenous confocal imaging of HClO and H2S in cells also. CS-N-ML's ability to target lysosomes positions indicated it could act as a lysosome-specific probe. It was discovered that the probes generate superoxide anions (O2•−) via a Type I mechanism. This discovery endows the probes with high photosensitizing activity even under hypoxic conditions. There is a positive correlation between the extent of the conjugated system and the photosensitivity of the probes, indicating that an enhanced conjugation leads to increased photosensitivity. Upon light irradiation, the probes generate ROS within HeLa cells. These results suggested that these probes can achieve theranostics for diseases associated with abnormal levels of HClO and H2S.

A Novel DNBS-based Fluorescent Probe for the Detection of H2S in Cells and on Test Strips.

Hydrogen sulfide (H2S) plays a key role in the physiology and pathology of organisms, and H2S in the environment is easily absorbed and harmful to health. It is of great significance to develop a probe with good selectivity, high sensitivity and good stability that can detect hydrogen sulfide inside and outside organisms. In this work, we designed a novel "turn-on" fluorescent probe CIM-SDB for the detection of H2S. The probe CIM-SDB used indene-carbazole as the fluorophore and 2,4-dinitrobenzenesulfonyl as the recognition site. The probe CIM-SDB exhibited high selectivity and sensitivity to H2S (detection limit as low as 123 nM). Moreover, the probe CIM-SDB was successfully applied to the detection of intracellular exogenous and endogenous H2S, and the test strips prepared by the probe CIM-SDB could realize the convenient and rapid detection of H2S.

A rhodol-based fluorescent probe for ratiometric sensing of hydrogen sulfide in living cells

Hydrogen sulfide is an important signaling molecule which plays a vital role in many biological processes. In this work, a novel near-infrared FRET (fluorescence resonance energy transfer) fluorescent probe was developed based on the rhodol derivative to detect H2S. The ratio of fluorescent intensity with the concentration of H2S exhibited an excellent linear relationship when probe LT responded to H2S. Probe LT exhibited excellent selectivity, sensitivity and anti-interference. LT was applied to sense endogenous and exogenous H2S in cells with great performance. Moreover, LT had the ability to target endoplasmic reticulum (ER) in Hela cells.

An efficient dual-function fluorescent probe for sulfites and sulfides and its imaging application in cells

As gas signaling molecules in organisms, SO2 derivatives and H2S play crucial regulating roles in a series of physiological processes. Therefore, developing an assay that can accurately monitor the concentration of SO2 derivatives and H2S in cells is extremely important for the research and treatment of related illnesses. A bifunctional probe SN-F based on FRET mechanism for SO2 derivatives and H2S was designed. SN-F had a short response time to SO2 (2 min), excellent anti-interference capability and selectivity in the non-organic solvent system (pH = 7.4), which was suitable for the determination of SO2 derivatives in cells. SN-F had a wide linear range for H2S. Moreover, SN-F was applied in cell imaging successfully with high targeting ability to endoplasmic reticulum (ER) and could monitor endogenous and exogenous H2S in cells.

Screening of H2S donors with a red emission mitochondria-targetable fluorescent probe: Toward discovering a new therapeutic strategy for Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disorder caused by various factors such as neuroinflammation, oxidative stress, mitochondrial dysfunction, and neuronal apoptosis. Recent studies have shown that H2S supplementation reverses neuronal loss and mitigates motor deficits in PD patients through anti-inflammatory, antioxidant, improved mitochondrial function and proautophagic. Therefore, the discovery and use of H2S donors may be an exciting and intriguing strategy for the treatment of PD. Herein, we report a red emission mitochondria-targetable fluorescent probe, Rho-H2S, which can specifically and sensitively detect H2S with a limit of detection of 62.5 nM. Bioimaging experiments have shown that the probe has excellent mitochondrial targeting and good imaging capabilities for the detection of exogenous and endogenous H2S in cells. More importantly, based on the Rho-H2S probe, we first confirmed the sulforaphane (SFN) among 15 glucosinolate and isothiocyanate compounds from cruciferous vegetables with an outstanding ability to release H2S and we further proved that SFN could alleviate the symptoms of PD in vivo. All results demonstrate that Rho-H2S could be an effective tool for screening H2S donors and can contribute to the development of new therapeutic strategies for PD.

Recent Progress in Fluorescent Probes for the Detection and Research of Hydrogen Sulfide in Cells

Hydrogen sulfide (H2S) is a gaseous signaling molecule that plays an important role in regulating various physiological activities in biological systems. As the fundamental structural and functional unit of organisms, cells are closely related to the homeostasis of their internal environment. The levels of H2S in different organelles maintain a certain balance, and any disruption of this balance will lead to various functional abnormalities that affect the health of organisms. Fluorescent imaging technology provides unique merits, such as simplicity, non-invasiveness, and real-time monitoring, and has become a powerful approach for the detection of molecules in biological systems. Based on the special physicochemical properties of H2S, numerous H2S-specific fluorogenic probes have been designed with different recognition mechanisms that enable rapid and accurate detection of H2S in cells. Therefore, this review briefly illustrates the design strategies, response principles, and biological applications of H2S-specific fluorescent probes and aims to provide relevant researchers with insight for future research.

Modulation of Near-Infrared Mitochondria-Targetable fluorescent probe for H2S bioimaging through the modification of heavy atom iodine

H2S is correlated with mitochondrial dysfunction, which results in the death of cells. Two near-infrared fluorescent probes, Mito-HS-1 and Mito-HS-2, were designed for mitochondrial H2S imaging. Initially, the synthesis protocol of expensive IR-780-based hemicyanine (HXPI) was optimized with an appreciate yield of 80 % as compared with 14–56 % previously reported. Iodine atom was introduced to HXPI to obtain iodine-HXPI whose Stokes shift was increased to be 90 nm. On account of the rapid and fast nucleophilic attack of H2S, HXPI-based Mito-HS-1 could be applied for the real time imaging of mitochondrial H2S. Besides some similar optical properties with Mito-HS-1, iodine-HXPI-based Mito-HS-2 exhibited wider linear range (3–150 μM), more stable fluorescent imaging and more favorable specificity in vitro. Both Mito-HS-1 and Mito-HS-2 could be used to image exogenous H2S in cells, with Mito-HS-2 showing fairly better signal-to-noise. Additionally, the Pearson correlation coefficient of two probes demonstrated that they could successfully monitor mitochondrial H2S in A549 cells and Hela cells.

A novel near-infrared fluorescence probe for hydrogen sulfide detection and application in cell and mice imaging

We presented here a novel near-infrared fluorescent probe based on 2-(2′-hydroxyphenyl)benzothiazole -dicyanoisophorone as fluorophore and 2,4-dinitrobenzenesulfonyl moiety as detection functionalized group for the discrimination of hydrogen sulfide (H2S). Probe L exhibited good specificity and sensitivity “turn on” response at 720 nm with a large Stokes shift (155 nm), rapid response (<60 s) and low detection limit (3.15 × 10−7 M), which also could be identified by the naked eyes. Moreover, probe L was successfully used to image exogenous/endogenous H2S in cells and mice, which demonstrated its potential applications in living systems.

A novel near-infrared fluorescent probe with large Stokes shift for imagining hydrogen sulfide

Hydrogen sulfide (H2S) plays an important role in regulating varieties of important physiological and pathological processes. Thus the development of fluorescent probe for the detection of H2S is of great significance and has attracted much attention recently. Herein, we reported a novel near-infrared (NIR) emitting fluorescent probe WFP-PC, which contained a positive charged hemicyanine-based WFP-OH as fluorophore and thiobenzoate unit as a specific reaction site. After treated with H2S, the probe exhibited significant fluorescence enhancement and response time within 4 min and detection limit as low as 0.47 μM, accompanied by color changes from purple to blue. The probe was successfully applied to imaging the exogenous/endogenous H2S in cells and mice, suggesting it could be a promising molecular tool for H2S detection in living systems.

A novel near infrared probe with large Stokes shift for detection of H2S in living cells

Hydrogen sulfide (H2S) is an important gas signal molecule, which participates in a variety of pathological and physiological processes. In this paper, a novel near-infrared fluorescence probe (NIR-H2S) with azido as the reaction site was designed and synthesized. NIR-H2S utilizes the reducibility of H2S to detect H2S, which effectively avoids the interference of biological thiols. NIR-H2S is a D-π-A dye, and thiophene is the π-bridge, which can not only enhance the π conjugation of the molecules but also increase the vibrational flexibility of the molecules. Therefore, NIR-H2S shows a significant near-infrared (NIR) turn-on signal at 693 nm, with a large Stokes shift (258 nm). Cell imaging experiments show that NIR-H2S has high contrast imaging ability and can be used to detect H2S in cells. The excellent performance of NIR-H2S indicates that NIR-H2S is one of the valuable candidate probes for the detection of H2S in living cells.

Self-Produced Hydrogen Sulfide Improves Ethanol Fermentation by Saccharomyces cerevisiae and Other Yeast Species

Hydrogen sulfide (H2S) is a gas produced endogenously in organisms from the three domains of life. In mammals, it is involved in diverse physiological processes, including the regulation of blood pressure and its effects on memory. In contrast, in unicellular organisms, the physiological role of H2S has not been studied in detail. In yeast, for example, in the winemaking industry, H2S is an undesirable byproduct because of its rotten egg smell; however, its biological relevance during fermentation is not well understood. The effect of H2S in cells is linked to a posttranslational modification in cysteine residues known as S-persulfidation. In this paper, we evaluated S-persulfidation in the Saccharomyces cerevisiae proteome. We screened S-persulfidated proteins from cells growing in fermentable carbon sources, and we identified several glycolytic enzymes as S-persulfidation targets. Pyruvate kinase, catalyzing the last irreversible step of glycolysis, increased its activity in the presence of a H2S donor. Yeast cells treated with H2S increased ethanol production; moreover, mutant cells that endogenously accumulated H2S produced more ethanol and ATP during the exponential growth phase. This mechanism of the regulation of metabolism seems to be evolutionarily conserved in other yeast species, because H2S induces ethanol production in the pre-Whole-Genome Duplication species Kluyveromyces marxianus and Meyerozyma guilliermondii. Our results suggest a new role of H2S in the regulation of the metabolism during fermentation.

The coumarin-pyrazole dye for detection of hydrogen sulfide in cells

Fluorescent probes for H2S are often interfered by other thiols. In this work, a coumarin-pyrazole dye with 2,4-dinitrosulfonyl group was designed for the detection of H2S. The probe exhibits weak fluorescence in water due to the photo induced electron transfer (PET) by 2,4-dinitrosulfonyl. After the sulfonyl group is cleaved off by H2S, strong fluorescence appears. The probe can specifically detect H2S without being interfered by other biological thiols, and shows a wide applicable pH range, low detection and wide detection range. The excellent detection properties of the probe can also be used to detect endogenous and exogenous H2S in cells. In addition, the probes can be made into portable test paper for the detection of H2S in solutions and can detect H2S in different water samples.

Ratiometric Detection of H2S in Liver Injury by Activated Two-Wavelength Photoacoustic Imaging.

Metformin is commonly used for clinical treatment of type-2 diabetes, but long-term or overdose intake of metformin usually causes selective upregulation of H2S level in the liver, resulting in liver injury. Therefore, tracking the changes of H2S content in the liver would contribute to the prevention and diagnosis of liver injury. However, in the literature, there are few reports on ratiometric PA molecular probes for H2S detection in drug-induced liver injury (DILI). Accordingly, here we developed a H2S-activated ratiometric PA probe, namely BDP-H2S, based Aza-BODIPY dye for detecting the H2S upregulation of metformin-induced liver injury. Due to the intramolecular charge transfer (ICT) effect, BDP-H2S exhibited a strong PA signal at 770 nm. Following the response to H2S, its ICT effect was recovered which showed a decrement of PA770 and an enhancement of PA840. The ratiometric PA signal (PA840/PA770) showed excellent H2S selectivity response with a low limit of detection (0.59 μM). Bioimaging experiments demonstrated that the probe has been successfully used for ratiometric PA imaging of H2S in cells and metformin-induced liver injury in mice. Overall, the designed probe emerges as a powerful tool for noninvasive and accurate imaging of H2S level and tracking its distribution and variation in liver in-real time.

Development of an activatable hydrogen sulfide-specific two-photon fluorescent probe for bioimaging in an air pouch inflammation model.

Inflammation caused by traumatic, ischemic, infectious, autoimmune or toxic injury may further trigger cancer and even death. Overexpression of hydrogen sulfide (H2S) in vivo has been identified as a biomarker for various types of inflammation. Identification-responsive fluorescence imaging probes have broad application prospects for in vivo diagnosis of inflammation. However, it is a challenge to design an imaging probe that concurrently responds to the target molecules to improve the sensitivity and specificity of inflammation detection. Herein, we designed and synthesized an activatable two-photon fluorescent probe to detect H2S. Fl-H2S had high selectivity, excellent photostable signals and low detection limit for recognizing H2S. In addition, Fl-H2S showed excellent two-photon fluorescence properties in cell and liver tissue visualization experiments, with a penetration depth of up to 126 μm in liver tissue. Most importantly, the unique probe Fl-H2S was the first probe to monitor H2S levels in a mouse air pouch inflammation model by fluorescence imaging technology. We expect Fl-H2S to become an effective tool for longitudinal monitoring of inflammation, diagnosis of inflammation and prediction of underlying pathogenesis of related diseases by detecting H2S.

Highly Selective Fluorescent Probe Design for Visualizing Hepatic Hydrogen Sulfide in the Pathological Progression of Nonalcoholic Fatty Liver.

Hydrogen sulfide (H2S), emerging as an important gaseous signal, has attracted more and more attention for its key role in chronic fatty liver diseases. However, lacking tools for H2S-specific in situ detection, the changes of endogenous hepatic H2S levels in the pathological progression of chronic liver diseases are still unclear. To this end, we adopted a strategy of combining molecular probe design and nanofunctionalization to develop a highly selective near-infrared (NIR) fluorescent probe, which allows in vivo real-time monitoring of hepatic H2S levels in the process of nonalcoholic fatty liver disease (NAFLD). As a proof of strategy demonstration, we first designed NIR molecular probes for H2S sensing through chemical design and probe screening and then loaded molecular probes into mesoporous silicon nanomaterials (MSNs) with surface encapsulation using poly(ethylene glycol) to construct a highly selective probe MSN@CSN@PEG, with significantly improved selectivity and photostability. Moreover, MSN@CSN@PEG exhibited high selectivity and sensitivity for endogenous H2S in cells and tumors in vivo, eliminating the interference of a high concentration of biothiols and sulfhydryl proteins. Furthermore, the probe was applied to in situ intravital imaging and systematic assessment of hepatic H2S levels in different stages of NAFLD for the first time, which may offer a promising tool for the future study of fatty liver diseases and other chronic liver diseases.

Current Trends and Future Perspectives of Hydrogen Sulfide Donors

ABSTRACT: Hydrogen sulfide (H2S) gas is included to be the most critical endogenous gasotransmitters that has several pathophysiological effects in many human cells and organ tissues. The synthesis of endogenous H2S in cells via several pathways. Variant biological effects of H2S including ion channel regulation, redox regulation of protein, thiols, polysulfides, thiosulfate/sulfite, and anti-oxidant activities affecting many cellular and molecular reactions. Therefore, it is essential to review H2S chemical biology, methods of detection of H2S release and its effects on pathological and physiological functions along with their therapeutic uses, including cardiovascular protective activities, anti-inflammatory and anti-tumor activities of the H2S donors.

Diet and Hydrogen Sulfide Production in Mammals.

Significance: In recent times, it has emerged that some dietary sulfur compounds can act on mammalian cell signaling systems via their propensity to release hydrogen sulfide (H2S). H2S plays important biochemical and physiological roles in the heart, gastrointestinal tract, brain, kidney, and immune systems of mammals. Reduced levels of H2S in cells and tissues correlate with a spectrum of pathophysiological conditions, including heart disease, diabetes, obesity, and altered immune function. Recent Advances: In the last decade, researchers have now begun to explore the mechanisms by which dietary-derived sulfur compounds, in addition to cysteine, can act as sources of H2S. This research has led to the identified several compounds, organic sulfides, isothiocyanates, and inorganic sulfur species including sulfate that can act as potential sources of H2S in mammalian cells and tissues. Critical Issues: We have summarised progress made in the identification of dietary factors that can impact on endogenous H2S levels in mammals. We also describe current research focused on how some sulfur molecules present in dietary plants, and associated chemical analogues, act as sources of H2S, and discuss the biological properties of these molecules as studied in a range of in vitro and in vivo systems. Future Directions: The identification of sulfur compounds in edible plants that can act as novel H2S releasing molecules is intriguing. Research in this area could inform future studies exploring the impact of diet on H2S levels in mammalian systems. Despite recent progress, additional work is needed to determine the mechanisms by which H2S is released from these molecules following ingestions of dietary plants in humans, whether the amounts of H2S produced is of physiological significance following the metabolism of these compounds in vivo, and if diet could be used to manipulated H2S levels in humans. Importantly, this will lead to a better understanding of the biological significance of H2S generated from dietary sources, and this information could be used in the development of plant breeding initiatives to increase the levels of H2S releasing sulfur compounds in crops, or inform dietary intervention strategies that could be used to alter the levels of H2S in humans.

Sensing and Bioimaging of the Gaseous Signaling Molecule Hydrogen Sulfide by Near-Infrared Fluorescent Probes.

A fluorescent probe for the monitoring of H2S levels in living cells and organisms is highly desirable. In this regard, near-infrared (NIR) fluorescent probes have emerged as a promising tool. NIR-I and NIR-II probes have many significant advantages; for instance, NIR light penetrates deeper into tissue than light at visible wavelengths, and it causes less photodamage during biosample analysis and less autofluorescence, enabling higher signal-to-background ratios. Therefore, it is expected that fluorescent probes having emission in the NIR region are more suitable for in vivo imaging. Consequently, a considerable increase in reports of new H2S-responsive NIR fluorescent probes appeared in the literature. This review highlights the advances made in developing new NIR fluorescent probes aimed at the sensitive and selective detection of H2S in biological samples. Their applications in real-time monitoring of H2S in cells and in vivo for bioimaging of living cells/animals are emphasized. The selection of suitable dyes for designing NIR fluorescent probes, along with the principles and mechanisms involved for the sensing of H2S in the NIR region, are described. The discussions are focused on small-molecule and nanomaterials-based NIR probes.

A fluorescent probe for specific detection of cysteine in lysosomes via dual-color mode imaging.

Biothiols, as part of the reactive sulfur species (RSS), are a class of bioactive molecules that play important physiological roles in human body. However, due to the similarity in structure and reaction sites of biothiols, it is difficult to differentiated detection them at the same time. In this work, a fluorescent probe CM-NBD combined coumarin derivative and 7-nitrobenzofurazan has been developed, which can effectively detect biothiols through simple ether cleavage. Because of a specific location group, CM-NBD can well localize in lysosomes with a high co-localization coefficient. Interesting, due to the weakly acidic environment of lysosomes, Cys can be distinguished from Hcy/GSH and H2S via dual-color mode. The probe is able not only to image exogenous biothiols but also to discriminate Cys from Hcy/GSH and H2S in cells and zebrafish model.

A mitochondrial-targeted red fluorescent probe for detecting endogenous H2S in cells with high selectivity and development of a visual paper-based sensing platform

Hydrogen sulfide (H2S) is a lipid-soluble gas signal molecule that plays a vital role in numerous abnormal pathological courses. Therefore, monitoring the changes of intracellular H2S level is undoubtedly of great scientific significance. Here, a red fluorescent probe SXR was reported, which is in view of the ICT mechanism. SXR showed rapid response (∼6 min), excellent selectivity and large Stokes shift (∼90 nm) to H2S. In addition, fluorescent imaging experiments further proved that SXR could detect endogenous and exogenous H2S in mitochondria, which provided a powerful tool for in-depth study of H2S function in various physiological courses. More importantly, a convenient visual paper-based sensor platform was designed, proving the favorable practicability for quantitative scanning and detecting of H2S with smart phone.