Germline loss in C. elegans enhances longevity by disrupting adhesion between niche and stem cells.

Ageing and fertility are intertwined. Germline loss extends the lifespan in various organisms, termed gonadal longevity. However, the original longevity signal from the somatic gonad remains poorly understood. Here, we focused on the interaction between germline stem cells (GSCs) and their niche, the distal tip cells (DTCs), to explore the barely known longevity signal from the somatic gonad in C. elegans. We found that removing germline disrupts the cell adhesions between GSC and DTC, causing a significant transcriptomic change in DTC through hmp-2/ß-catenin and two GATA transcription factors, elt-3 and pqm-1 in this niche cell. Inhibiting elt-3 and pqm-1 in DTC suppresses gonadal longevity. Moreover, we further identified the TGF-ß ligand, tig-2, as the cytokine from DTC upon the loss of germline, which evokes the downstream gonadal longevity signalling throughout the body. Our findings thus reveal the source of the longevity signalling in response to germline removal, highlighting the stem cell niche as a critical signalling hub in ageing.

BLMP-1 is a critical temporal regulator of dietary-restriction-induced response in Caenorhabditis elegans.

The extrinsic diet and the intrinsic developmental programs are intertwined. Although extensive research has been conducted on how nutrition regulates development, whether and how developmental programs control the timing of nutritional responses remain barely known. Here, we report that a developmental timing regulator, BLMP-1/BLIMP1, governs the temporal response to dietary restriction (DR). At the end of larval development, BLMP-1 is induced and interacts with DR-activated PHA-4/FOXA, a key transcription factor responding to the reduced nutrition. By integrating temporal and nutritional signaling, the DR response regulates many development-related genes, including gska-3/GSK3ß, through BLMP-1-PHA-4 at the onset of adulthood. Upon DR, a precocious activation of BLMP-1 in early larval stages impairs neuronal development through gska-3, whereas the increase of gska-3 by BLMP-1-PHA-4 at the last larval stage suppresses WNT signaling in adulthood for DR-induced longevity. Our findings reveal a temporal checkpoint of the DR response that protects larval development and promotes adult health.

Liver-Selective Imidazolopyrazine Mitochondrial Uncoupler SHD865 Reverses Adiposity and Glucose Intolerance in Mice.

Excess body fat is a risk factor for metabolic diseases and is a leading preventable cause of morbidity and mortality worldwide. There is a strong need to find new treatments that decrease the burden of obesity and lower the risk of obesity-related comorbidities, including cardiovascular disease and type 2 diabetes. Pharmacologic mitochondrial uncouplers represent a potential treatment for obesity through their ability to increase nutrient oxidation. Herein, we report the in vitro and in vivo characterization of compound SHD865, the first compound to be studied in vivo in a newly discovered class of imidazolopyrazine mitochondrial uncouplers. SHD865 is a derivative of the furazanopyrazine uncoupler BAM15. SHD865 is a milder mitochondrial uncoupler than BAM15 that results in a lower maximal respiration rate. In a mouse model of diet-induced adiposity, 6-week treatment with SHD865 completely restored normal body composition and glucose tolerance to levels like those of chow-fed controls, without altering food intake. SHD865 treatment also corrected liver steatosis and plasma hyperlipidemia to normal levels comparable with chow-fed controls. SHD865 has maximal oral bioavailability in rats and slow clearance in human microsomes and hepatocytes. Collectively, these data identify the potential of imidazolopyrazine mitochondrial uncouplers as drug candidates for the treatment of obesity-related disorders.

Wearable Sensor Patch with Hydrogel Microneedles for In Situ Analysis of Interstitial Fluid.

Continuous real-time monitoring of biomarkers in interstitial fluid is essential for tracking metabolic changes and facilitating the early detection and management of chronic diseases such as diabetes. However, developing minimally invasive sensors for the in situ analysis of interstitial fluid and addressing signal delays remain a challenge. Here, we introduce a wearable sensor patch incorporating hydrogel microneedles for rapid, minimally invasive collection of interstitial fluid from the skin while simultaneously measuring biomarker levels in situ. The sensor patch is stretchable to accommodate the swelling of the hydrogel microneedles upon extracting interstitial fluid and adapts to skin deformation during measurements, ensuring consistent sensing performance in detecting model biomarker concentrations, such as glucose and lactate, in a mouse model. The sensor patch exhibits in vitro sensitivities of 0.024 ± 0.002 µA mM-1 for glucose and 0.0030 ± 0.0004 µA mM-1 for lactate, with corresponding linear ranges of 0.1-3 and 0.1-12 mM, respectively. For in vivo glucose sensing, the sensor patch demonstrates a sensitivity of 0.020 ± 0.001 µA mM-1 and a detection range of 1-8 mM. By integrating a predictive model, the sensor patch can analyze and compensate for signal delays, improving calibration reliability and providing guidance for potential optimization in sensing performance. The sensor patch is expected to serve as a minimally invasive platform for the in situ analysis of multiple biomarkers in interstitial fluid, offering a promising solution for continuous health monitoring and disease management.

Quantitative Determination of Water in Organic Liquids by Ambient Mass Spectrometry.

This study uses a rapid tandem mass-spectrometry method to determine water content in complex organic solutions. Emphasis is placed on trace-water analysis by a fast and accurate alternative to the Karl-Fischer method. In this new method, water is captured by a charge-labeled molecular probe. Water binds strongly with high specificity to the strongly electrophilic aldehyde site in a charge-labelled molecule (N-methylpyridinium); competitive binding by other analytes is effectively discriminated against in the mass-measurement step. Quantitative determinations are made over a wide concentration range, 0.001 % (10 ppm) to 99 %, with better than 10 % relative standard deviation, along with short (1 min) analysis times using small sample volumes (several µL). Applications include water measurement in simple organic solvents, for example, deuterated solvents, as well as in complex mixtures, for example, organic reaction mixtures. Additionally, this method allows for water monitoring in levitated droplets. Mechanistic investigations into the impact of water on important chemical processes in organic synthesis and environmental science are reported.

Identification and enrichment of a UV-induced degradant of Anagrelide drug substance.

Anagrelide (ANG) is a widely used drug for the treatment of essential thrombocytosis and myeloproliferative neoplasms. Recently, a new oxidative degradant was identified when the drug product capsule underwent stress testing. Full structural characterization of this previously unidentified degradant was conducted. Preliminary LC-MS analysis indicated the targeted degradant as a mono-oxygenated product of ANG. For the purpose of facile isolation and purification, various forced degradation conditions were screened to enrich the desired degradant, among which, pyridinium chlorochromate (PCC)-treatment effectively afforded a yield of 55 % unknown degradant. Following isolation by prep-HPLC, 1D and 2D NMR studies and HRMS characterization assigned the products as a pair of 5-hydroxy-Anagrelide (5-OH-ANG) enantiomers. A plausible mechanism of formation is proposed.

A moderate static magnetic field promotes C. elegans longevity through cytochrome P450s.

Ageing is co-regulated by genetic and environmental factors. Life on earth lives and evolves in a mild geomagnetic field. Yet, the biological effects of a moderate magnetic field on ageing and the underlying genetic mechanisms remain barely unknown. Here, we report that a moderate static magnetic field (SMF) extends the lifespan of Caenorhabditis elegans, a well-established model organism in ageing research. Consistently, the SMF-treated worms show improved motility and mitochondrial function when aged. We identified from the transcriptomic changes upon SMF treatment that the upregulation of three cytochrome P450 genes are required for SMF-induced longevity. Our findings thus reveal that proper SMF treatment could promote longevity through the well-conserved cytochrome P450 enzymes.

Smart soft contact lenses for continuous 24-hour monitoring of intraocular pressure in glaucoma care.

Continuous monitoring of intraocular pressure, particularly during sleep, remains a grand challenge in glaucoma care. Here we introduce a class of smart soft contact lenses, enabling the continuous 24-hour monitoring of intraocular pressure, even during sleep. Uniquely, the smart soft contact lenses are built upon various commercial brands of soft contact lenses without altering their intrinsic properties such as lens power, biocompatibility, softness, transparency, wettability, oxygen transmissibility, and overnight wearability. We show that the smart soft contact lenses can seamlessly fit across different corneal curvatures and thicknesses in human eyes and therefore accurately measure absolute intraocular pressure under ambulatory conditions. We perform a comprehensive set of in vivo evaluations in rabbit, dog, and human eyes from normal to hypertension to confirm the superior measurement accuracy, within-subject repeatability, and user comfort of the smart soft contact lenses beyond current wearable ocular tonometers. We envision that the smart soft contact lenses will be effective in glaucoma care.

Conversion of oxadiazolo[3,4-b]pyrazines to imidazo[4,5-b]pyrazines via a tandem reduction-cyclization sequence generates new mitochondrial uncouplers.

We report new mitochondrial uncouplers derived from the conversion of [1,2,5]oxadiazolo[3,4-b]pyrazines to 1H-imidazo[4,5-b]pyrazines. The in situ Fe-mediated reduction of the oxadiazole fragment followed by cyclization gave access to imidazopyrazines in moderate to good yields. A selection of orthoesters also allowed functionalization on the 2-position of the imidazole ring. This method afforded a variety of imidazopyrazine derivatives with varying substitution on the 2, 5 and 6 positions. Our studies suggest that both a 2-trifluoromethyl group and N-methylation are crucial for mitochondrial uncoupling capacity.

Ageing induces tissue-specific transcriptomic changes in Caenorhabditis elegans.

Ageing is a complex process with common and distinct features across tissues. Unveiling the underlying processes driving ageing in individual tissues is indispensable to decipher the mechanisms of organismal longevity. Caenorhabditis elegans is a well-established model organism that has spearheaded ageing research with the discovery of numerous genetic pathways controlling its lifespan. However, it remains challenging to dissect the ageing of worm tissues due to the limited description of tissue pathology and access to tissue-specific molecular changes during ageing. In this study, we isolated cells from five major tissues in young and old worms and profiled the age-induced transcriptomic changes within these tissues. We observed a striking diversity of ageing across tissues and identified different sets of longevity regulators therein. In addition, we found novel tissue-specific factors, including irx-1 and myrf-2, which control the integrity of the intestinal barrier and sarcomere structure during ageing respectively. This study demonstrates the complexity of ageing across worm tissues and highlights the power of tissue-specific transcriptomic profiling during ageing, which can serve as a resource to the field.

The decrease of intraflagellar transport impairs sensory perception and metabolism in ageing.

Sensory perception and metabolic homeostasis are known to deteriorate with ageing, impairing the health of aged animals, while mechanisms underlying their deterioration remain poorly understood. The potential interplay between the declining sensory perception and the impaired metabolism during ageing is also barely explored. Here, we report that the intraflagellar transport (IFT) in the cilia of sensory neurons is impaired in the aged nematode Caenorhabditis elegans due to a daf-19/RFX-modulated decrease of IFT components. We find that the reduced IFT in sensory cilia thus impairs sensory perception with ageing. Moreover, we demonstrate that whereas the IFT-dependent decrease of sensory perception in aged worms has a mild impact on the insulin/IGF-1 signalling, it remarkably suppresses AMP-activated protein kinase (AMPK) signalling across tissues. We show that upregulating daf-19/RFX effectively enhances IFT, sensory perception, AMPK activity and autophagy, promoting metabolic homeostasis and longevity. Our study determines an ageing pathway causing IFT decay and sensory perception deterioration, which in turn disrupts metabolism and healthy ageing.

Synthesis and Structure-Activity Relationship of Tetra-Substituted Cyclohexyl Diol Inhibitors of Proviral Insertion of Moloney Virus (PIM) Kinases.

Overexpression of PIM 1, 2, and 3 kinases is frequently observed in many malignancies. Previously, we discovered a potent and selective pan-PIM kinase inhibitor, compound 2, currently in phase I clinical trials. In this work, we were interested in replacing the amino group on the cyclohexane ring in compound 2 with a hydroxyl group. Structure-based drug design led to cellularly potent but metabolically unstable tetra-substituted cyclohexyl diols. Efforts on the reduction of Log D by introducing polar heterocycles improved metabolic stability. Incorporating fluorine to the tetra-substituted cyclohexyl diol moiety further reduced Log D, resulting in compound 14, a cellularly potent tetra-substituted cyclohexyl diol inhibitor with moderate metabolic stability and good permeability. We also describe the development of efficient and scalable synthetic routes toward synthetically challenging tetra-substituted cyclohexyl diol compounds. In particular, intermediate 36 was identified as a versatile intermediate, enabling a large-scale synthesis of highly substituted cyclohexane derivatives.

Uniform High-k Amorphous Native Oxide Synthesized by Oxygen Plasma for Top-Gated Transistors.

The integration of high-k gate dielectrics with two-dimensional (2D) semiconducting channel materials is essential for high-performance and low-power electronics. However, the conformal deposition of a uniform high-k dielectric with sub-1 nm equivalent oxide thickness (EOT) and high interface quality on high-mobility 2D semiconductors is still challenging. Here, we report a facile approach to synthesize a uniform high-k (εr ∼ 22) amorphous native oxide Bi2SeOx on the high-mobility 2D semiconducting Bi2O2Se using O2 plasma at room temperature. The conformal native oxide can directly serve as gate dielectrics with EOT of ∼0.9 nm, while the original properties of underlying 2D Bi2O2Se is preserved. Furthermore, high-resolution area-selective oxidation of Bi2O2Se is achieved to fabricate discrete electronic components. This facile integration of a high-mobility 2D semiconductor and its high-k native oxide holds high promise for next-generation nanoelectronics.

[1,2,5]Oxadiazolo[3,4-b]pyrazine-5,6-diamine Derivatives as Mitochondrial Uncouplers for the Potential Treatment of Nonalcoholic Steatohepatitis.

Small molecule mitochondrial uncouplers are emerging as a new class of molecules for the treatment of nonalcoholic steatohepatitis. We utilized BAM15, a potent protonophore that uncouples the mitochondria without depolarizing the plasma membrane, as a lead compound for structure-activity profiling. Using oxygen consumption rate as an assay for determining uncoupling activity, changes on the 5- and 6-position of the oxadiazolopyrazine core were introduced. Our studies suggest that unsymmetrical aniline derivatives bearing electron withdrawing groups are preferred compared to the symmetrical counterparts. In addition, alkyl substituents are not tolerated, and the N-H proton of the aniline ring is responsible for the protonophore activity. In particular, compound 10b had an EC50 value of 190 nM in L6 myoblast cells. In an in vivo model of NASH, 10b decreased liver triglyceride levels and showed improvement in fibrosis, inflammation, and plasma ALT. Taken together, our studies indicate that mitochondrial uncouplers have potential for the treatment of NASH.

Anibamine and Its Analogues: Potent Antiplasmodial Agents from Aniba citrifolia.

In our continuing search for novel natural products with antiplasmodial activity, an extract of Aniba citrifolia was found to have good activity, with an IC50 value less than 1.25 µg/mL. After bioassay-directed fractionation, the known indolizinium alkaloid anibamine (1) and the new indolizinium alkaloid anibamine B (2) were isolated as the major bioactive constituents, with antiplasmodial IC50 values of 0.170 and 0.244 µM against the drug-resistant Dd2 strain of Plasmodium falciparum. The new coumarin anibomarin A (3), the new norneolignan anibignan A (5), and six known neolignans (7-12) were also obtained. The structures of all the isolated compounds were determined based on analyses of 1D and 2D NMR spectroscopic and mass spectrometric data, and the absolute configuration of anibignan A (5) was assigned from its ECD spectrum. Evaluation of a library of 28 anibamine analogues (13-40) indicated that quaternary charged analogues had IC50 values as low as 58 nM, while uncharged analogues were inactive or significantly less active. Assessment of the potential effects of anibamine and its analogues on the intraerythrocytic stages and morphological development of P. falciparum revealed substantial activity against ring stages for compounds with two C-10 side chains, while those with only one C-10 side chain exhibited substantial activity against trophozoite stages, suggesting different mechanisms of action.

Molecular recognition of HIV-1 RNAs with branched peptides.

Targeting RNA offers the potential in many diseases of a therapeutic treatment. Due to its large surface area and ability to adopt different conformations, targeting RNA has proven challenging. Medium-sized branched peptides are of the size to competitively bind RNA while remaining cell permeable, stable in vivo, and non-toxic. Additionally, the ease in generating a large library followed by high-throughput screening provides a way to suggest a scaffold with high diversity that is capable of targeting the structure and sequence of RNA. The ability to select various types of amino acid modifications in the branched peptide allows for variable structures and interactions of the branched peptide but can result in too large a task if not approached properly. In this chapter, we discuss a strategy to selectively recognize RNAs of interest through high throughput screening of branched peptides, validation of hits and biophysical characterization, leading by example with our experience in targeting HIV-1 RNAs with branched peptides.

Molecular recognition of a branched peptide with HIV-1 Rev Response Element (RRE) RNA.

Interaction of HIV-1 rev response element (RRE) RNA with its cognate protein, Rev, is critical for HIV-1 replication. Understanding the mode of interaction between RRE RNA and ligands at the binding site can facilitate RNA molecular recognition as well as provide a strategy for developing anti-HIV therapeutics. Our approach utilizes branched peptides as a scaffold for multivalent binding to RRE IIB (high affinity rev binding site) with incorporation of unnatural amino acids to increase affinity via non-canonical interactions with the RNA. Previous high throughput screening of a 46,656-member library revealed several hits that bound RRE IIB RNA in the sub-micromolar range. In particular, the lead compound, 4B3, displayed a Kd value of 410 nM and demonstrated selectivity towards RRE. A ribonuclease protection assay revealed that 4B3 binds to the stem-loop structure of RRE IIB RNA, which was confirmed by SHAPE analysis with 234 nt long NL4-3 RRE RNA. Our studies further indicated interaction of 4B3 with both primary and secondary Rev binding sites.

Efficacy of a Covalent ERK1/2 Inhibitor, CC-90003, in KRAS-Mutant Cancer Models Reveals Novel Mechanisms of Response and Resistance.

As a critical signaling node, ERK1/2 are attractive drug targets, particularly in tumors driven by activation of the MAPK pathway. Utility of targeting the MAPK pathway has been demonstrated by clinical responses to inhibitors of MEK1/2 or RAF kinases in some mutant BRAF-activated malignancies. Unlike tumors with mutations in BRAF, those with mutations in KRAS (>30% of all cancers and >90% of certain cancer types) are generally not responsive to inhibitors of MEK1/2 or RAF. Here, a covalent ERK1/2 inhibitor, CC-90003, was characterized and shown to be active in preclinical models of KRAS-mutant tumors. A unique occupancy assay was used to understand the mechanism of resistance in a KRAS-mutant patient-derived xenograft (PDX) model of colorectal cancer. Finally, combination of CC-90003 with docetaxel achieved full tumor regression and prevented tumor regrowth after cessation of treatment in a PDX model of lung cancer. This effect corresponded to changes in a stemness gene network, revealing a potential effect on tumor stem cell reprograming. IMPLICATIONS: Here, a covalent ERK1/2 inhibitor (CC-90003) is demonstrated to have preclinical efficacy in models of KRAS-mutant tumors, which present a therapeutic challenge for currently available therapies.

Discovery of a Branched Peptide That Recognizes the Rev Response Element (RRE) RNA and Blocks HIV-1 Replication.

We synthesized and screened a unique 46 656-member library composed of unnatural amino acids that revealed several hits against RRE IIB RNA. Among the hit peptides identified, peptide 4A5 was found to be selective against competitor RNAs and inhibited HIV-1 Rev-RRE RNA interaction in cell culture in a p24 ELISA assay. Biophysical characterization in a ribonuclease protection assay suggested that 4A5 bound to the stem-loop region in RRE IIB while SHAPE MaP probing with 234 nt RRE RNA indicated additional interaction with secondary Rev binding sites. Taken together, our investigation suggests that HIV replication is inhibited by 4A5 blocking binding of Rev and subsequent multimerization.

Novel Bioactive Natural Products Isolated from Madagascar Plants and Marine Organisms (2009-2017).

Madagascar's rain forests and tropical dry forests are home to numerous endemic plant species and the island is considered a biodiversity hotspot. About 80% of the Madagascan (Malagasy) population relies on traditional medicines that have been proven to contain a variety of biologically active compounds. In the search for bioactive compounds from Madagascan biodiversity, we accessed and collected most of the literature dealing with the isolation, structure elucidation, and biological activities of organic small molecules originating from Madagascan plants and marine organisms. Since we published the first review of this work in 2009 (Curr. Med. Chem., 17, 2010, Hou and Harinantenaina), the present paper covers the isolation, structures, and bioactivity of 182 new secondary metabolites isolated from Malagasy higher plants and marine organisms in the last seven years (2009-2017).