Proteolysis targeting chimera technology:a novel strategy for treating diseases of the central nervous system

Neurological diseases such as stroke,Alzheimer’s disease,Parkinson’s disease,and Huntington’s disease are among the intractable diseases for which appropriate drugs and treatments are lacking.Proteolysis targeting chimera(PROTAC)technology is a novel strategy to solve this problem.PROTAC technology uses the ubiquitin-protease system to eliminate mutated,denatured,and harmful proteins in cells.It can be reused,and utilizes the protein destruction mechanism of the cells,thus making up for the deficiencies of traditional protein degradation methods.It can effectively target and degrade proteins,including proteins that are difficult to identify and bind.Therefore,it has extremely important implications for drug development and the treatment of neurological diseases.At present,the targeted degradation of mutant BTK,mHTT,Tau,EGFR,and other proteins using PROTAC technology is gaining attention.It is expected that corresponding treatment of nervous system diseases can be achieved.This review first focuses on the recent developments in PROTAC technology in terms of protein degradation,drug production,and treatment of central nervous system diseases,and then discusses its limitations.This review will provide a brief overview of the recent application of PROTAC technology in the treatment of central nervous system diseases.

Amino Acid Biosynthesis and Proteolysis in <i>Lactobacillus Bulgaricus</i>Revisited: A Genomic Comparison

The amino acid biosynthesis and proteolytic system of Lactobacillus bulgaricus (L.Bulgaricus ) is important for its growth in niche-specific environments, as well as for flavour formation in the food industry. Comparative analyses of 4 completed sequences of the L.Bulgaricus strain genome on a genomic scale revealed that genes involved in amino acids synthesis were undergoing reductive evolution. However, the selected industrial strains, namely, L.Bulgaricus 2038 and L.Bulgaricus ND02, retained more complete genes in the amino acid synthesis and proteolytic system category than the laboratory strains, and have some unique genes and pathways for obtaining amino acids that enable these bacteria to adapt to their various environmental niches.

Inhibitors of protein kinases affecting cAMP-dependent proteolysis of GATA-6

We screened 95 kinase inhibitors whether they affect cAMP-dependent proteolysis of GATA-6 or not. Among them 7 inhibitors inhibited the proteolysis at the concentration range of μM around their IC50. They are inhibitors for protein kinase A (H-89 and 4- cyano-3-methylisoquinoline), c-Jun N-terminal kinase (SP600125), phosphatidylinositol 3-kinase (Wort- mannin and LY-294002), casein kinase II (TBB) and cyclin dependent kinase (Cdk1/2 inhibitor III). It is of interest how these kinases play roles in the degradation process of GATA-6 since this transcription factor is essential for development and tissue-specific gene expression of mammals. Inhibitors identified in this study would be helpful to study molecular mechanisms of phenomena in which GATA-6 participates.

Liposome-encapsulated dimethyl curcumin inhibits over-activation of rat lymphocyte to relieve collagen-induced arthritis by regulating intracellular proteolysis and PCNA/p21/caspase-3 pathway

Dimethyl curcumin,a synthetic derivative of curcumin,has good anti-cancer,anti-arthritis and anti-inflammatory properties,but underline mechanism was unclear.Activation,differentiation,proliferation and apoptosis of lymphocytes have important functions during arthritis development and immune homeostasis.Over-activation of lymphocyte causes inflammatory cytokines storm,leading to an immune imbalance and tissue damages.The aim of this study was to investigate the anti-inflammation mechanism of liposome encapsulated dimethyl curcumin(Lipo-DiMC)on over-activated rat spleen lymphocytes.In this study,Lipo-DiMC was produced to increase the solubility;the primary rat spleen lymphocytes were extracted and the Concanavalin A induced cell activation model was established to study the cellular responses to Lipo-DiMC treatment in-vitro.The results showed that Lipo-DiMC suppressed Concanavalin A-induced cell proliferation,inhibited cells entering G2/M phase,and reduced the ratio of necrosis/apoptosis by manipulating intracellular p53/p21/PCNA/JNK-1 pathways.Furthermore,Lipo-DiMC increased the accumulations of intracellular matrix metalloproteinase-9 and reduced matrix metalloproteinase-9 secretion of rat spleen lymphocytes.Also,Lipo-DiMC increased intracellular caspase-3 expression and reduced Cat-C activity in activated rat spleen lymphocytes,involving in intracellular proteolysis.Our findings suggest that dimethyl curcumin effectively alleviates Concanavalin A induced over-activation of rat spleen lymphocytes,thereby inhibiting inflammatory cytokines storm and restoring cell homeostasis.

A Proximity-Triggered Strategy toward Transferable Proteolysis Targeting Chimeras

Over the past 20 years,great efforts have been invested in developing site-specific approaches to protein modification to dissect protein functions directly and accurately.Here,we report a proximitytriggered group transfer strategy from a sulfonium warhead to a Cysteine(Cys)residue of the target protein.With a guiding ligand,cargoes could be transferred selectively from a sulfonium center onto the Cys residue in the vicinity of their binding interface.The successful thalidomide transfer of sulfonium 1-X could be applied intracellularly for epidermal growth factor receptor degradation,highlighting the potential of group transfer strategy as a suite of chemical biology studies,including cell imaging,protein profiling,and protein degradation by simply employing different transferrable groups.

Emerging structures and dynamic mechanisms ofγ-secretase for Alzheimer’s disease

γ-Secretase,called“the proteasome of the membrane,”is a membrane-embedded protease complex that cleaves 150+peptide substrates with central roles in biology and medicine,including amyloid precursor protein and the Notch family of cell-surface receptors.Mutations inγ-secretase and amyloid precursor protein lead to early-onset familial Alzheimer’s disease.γ-Secretase has thus served as a critical drug target for treating familial Alzheimer’s disease and the more common late-onset Alzheimer’s disease as well.However,critical gaps remain in understanding the mechanisms of processive proteolysis of substrates,the effects of familial Alzheimer’s disease mutations,and allosteric modulation of substrate cleavage byγ-secretase.In this review,we focus on recent studies of structural dynamic mechanisms ofγ-secretase.Different mechanisms,including the“Fit-Stay-Trim,”“Sliding-Unwinding,”and“Tilting-Unwinding,”have been proposed for substrate proteolysis of amyloid precursor protein byγ-secretase based on all-atom molecular dynamics simulations.While an incorrect registry of the Notch1 substrate was identified in the cryo-electron microscopy structure of Notch1-boundγ-secretase,molecular dynamics simulations on a resolved model of Notch1-boundγ-secretase that was reconstructed using the amyloid precursor protein-boundγ-secretase as a template successfully capturedγ-secretase activation for proper cleavages of both wildtype and mutant Notch,being consistent with biochemical experimental findings.The approach could be potentially applied to decipher the processing mechanisms of various substrates byγ-secretase.In addition,controversy over the effects of familial Alzheimer’s disease mutations,particularly the issue of whether they stabilize or destabilizeγ-secretase-substrate complexes,is discussed.Finally,an outlook is provided for future studies ofγ-secretase,including pathways of substrate binding and product release,effects of modulators on familial Alzheimer’s disease mutations of theγ-secretase-substrate complexes.Comprehensive understanding of the functional mechanisms ofγ-secretase will greatly facilitate the rational design of effective drug molecules for treating familial Alzheimer’s disease and perhaps Alzheimer’s disease in general.

Elucidation of potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa

Dry-cured meat products are considerably popular around the world due to unique flavor.Proteolysis is one of the enzymatic reactions from which flavor substances are derived,which is affected by endogenous proteases.The purpose aimed to reveal the potential relationship between endogenous proteases and key flavor substances in dry-cured pork coppa in this paper.The dynamic changes of endogenous proteases activity,free amino acids,and volatiles during dry-cured pork coppa processing were characterized.The results showed that 5 kinds of free amino acids,Glu,Lys,Val,Ala,and Leu,were identified as significant contributors to taste.Meanwhile,key volatiles,such as hexanal,nonanal,octanal,benzaldehyde,3-methyl butanoic acid,2-methyl propanoic acid,and ethyl octanoate,greatly contributed to the flavor characteristics of dry-cured pork coppa.Further partial correlation analysis was performed to better elucidate the relationship among parameters.The results revealed that close relationship between endogenous proteases and key substances.RAP not only significantly affected the accumulation of key active-amino acids,but also affected the accumulation of ethyl octanoate,2,3-pentanedione,and 2,3-octanedione by regulating the accumulation of octanoic acid and Leu.In addition,cathepsin B and D,DPP II,DPP IV and RAP notably affected accumulation of hexanal.

Impact of sourdough fermentation on nutrient transformations in cereal-based foods:Mechanisms,practical applications,and health implications

Sourdough is often considered a healthy choice and quality improver for use in cereal production due to its unique microbial composition and fermentation properties.During sourdough fermentation of cereals,biotransformation of nutrients occurs,resulting in notable changes to proteins,carbohydrates,fats,vitamins,and minerals.Each nutrient undergoes specific transformations,providing various advantages for human health.Proteins undergo hydrolysis to produce small molecular weight peptides and amino acids that are more easily digested and absorbed by the human body.Carbohydrates break down to improve the digestibility and absorption of cereals and lower the glycemic index.Fatty acids experience oxidation to produce new substances with health benefits.Additionally,the application of sourdough fermentation can enhance the texture,flavor,and nutritional value of cereal foods while also extending their shelf life and improving food safety.In conclusion,sourdough fermentation has a broad range of applications in cereal food processing.Further research is encouraged to investigate the mechanisms and processes of sourdough fermentation to develop even more nutritious,healthy,and flavorful cereal-based foods.

Nuclear Localized O-Fucosyltransferase SPY Facilitates PRR5 Proteolysis to Fine-Tune the Pace of Arabidopsis Circadian Clock

Post-translational modifications play essential roles in finely modulating eukaryotic circadian clock systems.In plants,the effects of O-glycosylation on the circadian clock and the underlying mechanisms remain largely unknown.The O-fucosyltransferase SPINDLY(SPY)and the O-GIcNAc transferase SECRET AGENT(SEC)are two prominent O-glycosylation enzymes in higher plants,with both overlapped and unique functions in plant growth and development.Unlike the critical role of O-GIcNAc in regulating the animal circadian clock,here we report that nuclear-localized SPY,but not SEC,specifically modulates the pace of the Arabidopsis circadian clock.By identifying the interactome of SPY,we identified PSEUDORESPONSE REGULATOR 5(PRR5),one of the core circadian clock components,as a new SPY-interacting protein.PRR5 can be O-fucosylated by SPY in pianta,while point mutation in the catalytic domain of SPY abolishes the O-fucosylation of PRR5.The protein abundance of PRR5 is strongly increased in spy mutants,while the degradation rate of PRR5 is much reduced,suggesting that PRR5 proteolysis is promoted by SPY-mediated O-fucosylation.Moreover,multiple lines of genetic evidence indicate that PRR5 is a major downstream target of SPY to specifically mediate its modulation of the circadian clock.Collectively,our findings provide novel insights into the specific role of the O-fucosyltransferase activity of SPY in modulating the circadian clock and implicate that O-glycosylation might play an evolutionarily conserved role in modulating the circadian clock system,via O-GIcNAcylation in mammals,but via O-fuco-sylation in higher plants.

Recent advances in proteolysis and peptide/protein separation by chromatographic strategies

This review gives a broad glance on the progress of recent advances on proteolysis and peptide/protein separation by chroma-tographic strategies in the past ten years, covering the main research in these areas especially in China. The reviewed research focused on enzymatic micro-reactors and peptide separation in bottom-up approaches, and protein and peptide separation in top-down approaches. The new enzymatic micro-reactor is able to accelerate proteolytic reaction rate from conventionally a couple of hours to a few seconds, and the multiple dimensional chromatographic-separation with various models or arrays could sufficiently separate the proteomic mixture. These advances have significantly promoted the research of protein/peptide separation and identification in proteomics.

Design and Synthesis of Proteolysis Targeting Chimeras for Inducing BRD4 Protein Degradation

In this paper, we synthesized a series of proteolysis targeting chimeras（PROTACs） using VHL E3 ligase ligands for BRD4 protein degradation. One of the most promising compound 19g exhibited robust potency of BRD4 inhibition with IC50 value of （18.6±1.3） nmol/L, respectively. Furthermore, compound 19g potently inhibited cell proliferation in BRIM-sensitive cell lines RS4;11 with IC50 value of （34.2±4.3） nmol/L and capable of inducing de- gradation of BRD4 protein at 0.4-0.6 μmol/L in the RS4;11 leukemia cells. These data show that compound 19g is a highly potent and efficacious BRIM degrader.

Identification in Lupin Seed of a Serine- Endopeptidase Activity Cleaving between Twin Arginine Pairs and Causing Limited Proteolysis of Seed Storage Proteins

The occurrence of twin-arginine motifs （-R-R-） in the amino acid sequences of animal pro-proteins frequently defines the cleavage site（s） for their structural/functional maturation. No information is available on the presence and possible biological meaning of these motifs in the seed storage proteins. In this work, a novel endopeptidase activity with cleavage specificity to twin-arginine pairs has been detected in mature dry Lupinus albus seeds. The endopeptidase was tested with a number of endogenous and exogenous protein substrates, which were selected according to the pres- ence of one or more twin-arginine residue motifs in their amino acid sequences. The observed hydrolysis patterns were limited and highly specific. Partial proteolysis led to stable polypeptide fragments that were characterized by 1- and 2-D electrophoresis. Selected polypeptides were submitted to N-terminal amino acid sequencing and mass spectrometry anal- yses, These approaches, supported by bioinformatic analysis of the available sequences, allowed the conclusion that the polypeptide cleavage events had occurred at the peptide bonds comprised between twin-arginine residue pairs with all tested protein substrates. The endopeptidase activity was inhibited by 4-（2-AminoEthyl）Benzene-Sulphonyl Fluoride hy- drochloride （AEBSF）, leupeptin, and serine proteinase protein inhibitors, while it was not affected by pepstatin, trans- EpoxysuccinyI-L-leucylamido（4-guanidino）butane （E64）, and ethylenediaminetetraacetic acid （EDTA）, thus qualifying the Arg-Arg cleaving enzyme as a serine endopeptidase. The structural features of storage proteins from lupin and other legume seeds strongly support the hypothesis that the occurrence of an endopeptidase activity cleaving -R-R- bonds may be functional to facilitate their degradation at germination and possibly generate polypeptide fragments with specific biological activity.

Probing the Proteolysis of Melitin Using Liquid Secondary Ion Mass Spectrometry

Liquid secondary ion mass spectrometry(LSIMS) was used to probe the proteolysis of melittin by trypsin and pepsin. The results showed that LSIMS is good for monitoring proteolytic reactions. It can not only identify the proteolytic products of proteins, but also be used to research the dynamics of proteolytic reactions. The proteolysis of melittin by trypsin gave seven main peptide fragments: 1, AA 1 AA 7 ; 2, AA 1 AA 21 ;3, AA 1 AA 22 ; 4, AA 1 AA 23 ; 5, AA 1 AA 24 ; 6, AA 8 AA 21 ; 7, AA 8 AA 22 . The proteolysis of melittin with pepsin gave thirteen peptide fragments: 1, AA 1 AA 3; 2, AA 4 AA 6;3, AA 1 AA 4;4, AA 1 AA 5 ;5, AA 1 AA 6 ;6, AA 1 AA 8;7, AA 7 AA 13 ;8, AA 10 AA 13 ;9, AA 14 AA 16 ;10, AA 14 AA 26 ;11, AA 15 AA 26 ;12, AA 17 AA 26 ;13, AA 20 AA 26 .

Characterization of SARS-COV-2 main protease inhibitory peptides from Ulva prolifera proteins

The main protease(M^(pro))is essential for the replication of SARS-COV-2 and therefore represents a promising anti-viral target.In this study,we screened M^(pro)inhibitory peptides from Ulva prolifera protein on in-silico proteolysis.Cytotoxicity analysis using the online toxic prediction tool ToxinPred revealed that all the peptides were non-cytotoxic.The hexapeptide(SSGFID)exhibited high M^(pro)inhibitory activity in molecular docking and its IC_(50)value was 139.40±0.82μmol/L in vitro according to fluorescence resonance energy transfer assay(FRET).Quantitative real-time(qRT-)PCR results show that SSGFID could stimulate the expression of mitosis-related factors,including nuclear factor-κB,cyclin D1,and cyclin-dependent kinase 4,to promote the proliferation of mice splenocytes.Stability study revealed that SSGFID showed resistance against pepsin and trypsin but lost D(Asp)after pretreatment at121℃ for 15 min.Besides,SSGFID was mainly transported through the Caco-2 cell monolayer by the peptide transporter PepT1 and passive-mediated transport during the transport study.Unfortunately,the peptide was also degraded by Caco-2 intracellular enzymes,and the transfer rate of intact peptide was4.2%.Furthermore,Lineweaver–Burk plots demonstrated that SSGFID possessed a mixed inhibitory characteristic with M^(pro).Our study indicated the potential of Ulva prolifera as antiviral and immuneenhancing functional food ingredients and nutraceuticals.

Applications and prospects of cryo-EM in drug discovery

Drug discovery is a crucial part of human healthcare and has dramatically benefited human lifespan and life quality in recent centuries, however, it is usually time-and effort-consuming. Structural biology has been demonstrated as a powerful tool to accelerate drug development. Among different techniques, cryo-electron microscopy(cryo-EM) is emerging as the mainstream of structure determination of biomacromolecules in the past decade and has received increasing attention from the pharmaceutical industry. Although cryo-EM still has limitations in resolution, speed and throughput, a growing number of innovative drugs are being developed with the help of cryo-EM. Here, we aim to provide an overview of how cryo-EM techniques are applied to facilitate drug discovery. The development and typical workflow of cryo-EM technique will be briefly introduced, followed by its specific applications in structure-based drug design, fragment-based drug discovery, proteolysis targeting chimeras, antibody drug development and drug repurposing. Besides cryo-EM, drug discovery innovation usually involves other state-of-the-art techniques such as artificial intelligence(AI), which is increasingly active in diverse areas. The combination of cryo-EM and AI provides an opportunity to minimize limitations of cryo-EM such as automation, throughput and interpretation of mediumresolution maps, and tends to be the new direction of future development of cryo-EM. The rapid development of cryo-EM will make it as an indispensable part of modern drug discovery.

Cellular response toβ-amyloid neurotoxicity in Alzheimer's disease and implications in new therapeutics

β-Amyloid(Aβ)is a specific pathological hallmark of Alzheimer's disease(AD).Because of its neurotoxicity,AD patients exhibit multiple brain dysfunctions.Disease-modifying therapy(DMT)is the central concept in the development of AD thera-peutics today,and most DMT drugs that are currently in clinical trials are anti-Aβdrugs,such as aducanumab and lecanemab.Therefore,understanding Aβ's neurotoxic mechanism is crucial for Aβ-targeted drug development.Despite its total length of only a few dozen amino acids,Aβis incredibly diverse.In addition to the well-known Aβ_(1-42),N-terminally truncated,glutaminyl cyclase(QC)catalyzed,and pyroglutamate-modified Aβ(pEAβ)is also highly amyloidogenic and far more cytotoxic.The extracel-lular monomeric Aβ_(x-42)(x=1-11)initiates the aggregation to form fibrils and plaques and causes many abnormal cellular responses through cell membrane receptors and receptor-coupled signal pathways.These signal cascades further influence many cel-lular metabolism-related processes,such as gene expression,cell cycle,and cell fate,and ultimately cause severe neural cell damage.However,endogenous cellular anti-Aβdefense processes always accompany the Aβ-induced microenvironment alterations.Aβ-cleaving endopeptidases,Aβ-degrading ubiquitin-proteasome system(UPS),and Aβ-engulfing glial cell immune responses are all essential self-defense mechanisms that we can leverage to develop new drugs.This review discusses some of the most recent advances in understanding Aβ-centric AD mechanisms and suggests prospects for promising anti-Aβstrategies.

Chimeric molecules facilitate the degradation of androgen receptors and repress the growth of LNCaP cells

Post-translational degradation of protein plays an important role in cell life. We employed chimeric molecules （dihydrotestosterone-based proteolysis-targeting chimeric molecule [DHT-PROTAC]） to facilitate androgen receptor （AR） degradation via the ubiquitin-proteasome pathway （UPP） and to investigate the role of AR in cell proliferation and viability in androgen-sensitive prostate cancer cells. Western blot analysis and immunohistochemistry were applied to analyse AR levels in LNCaP cells after DHT-PROTAC treatment. Cell counting and the 3-（4,5-dimethylthiazol-2-yl）-2,5- diphenyl tetrazolium bromide （MTT） cell viability assay were used to evaluate cell proliferation and viability after AR elimination in both LNCaP and PC-3 cells. AR was tagged for elimination via the UPP by DHT-PROTAC, and this could be blocked by proteasome inhibitors. Degradation of AR depended on DHT-PROTAC concentration, and either DHT or an ALAPYIP-（arg）8 peptide could compete with DHT-PROTAC. Inhibition of cell proliferation and decreased viability were observed in LNCaP cells, but not in PC-3 or 786-0 cells after DHT-PROTAC treatment. These data indicate that AR elimination is facilitated via the UPP by DHT-PROTAC, and that the growth of LNCaP cells is repressed after AR degradation.

Does intra-ruminal nitrogen recycling waste valuable resources? A review of major players and their manipulation

Nitrogenous emissions from ruminant livestock production are of increasing public concern and, together with methane, contribute to environmental pollution. The main cause of nitrogen-(N)-containing emissions is the inadequate provision of N to ruminants, leading to an excess of ammonia in the rumen, which is subsequently excreted. Depending on the size and molecular structure, various bacterial, protozoal and fungal species are involved in the ruminal breakdown of nitrogenous compounds(NC). Decelerating ruminal NC degradation by controlling the abundance and activity of proteolytic and deaminating microorganisms, but without reducing cellulolytic processes, is a promising strategy to decrease N emissions along with increasing N utilization by ruminants. Different dietary options, including among others the treatment of feedstuffs with heat or the application of diverse feed additives, as well as vaccination against rumen microorganisms or their enzymes have been evaluated. Thereby, reduced productions of microbial metabolites, e.g. ammonia, and increased microbial N flows give evidence for an improved N retention. However, linkage between these findings and alterations in the rumen microbiota composition, particularly NC-degrading microbes, remains sparse and contradictory findings confound the exact evaluation of these manipulating strategies, thus emphasizing the need for comprehensive research. The demand for increased sustainability in ruminant livestock production requests to apply attention to microbial N utilization efficiency and this will require a better understanding of underlying metabolic processes as well as composition and interactions of ruminal NC-degrading microorganisms.

Role of calpain system in meat tenderness: A review

Aging is a popular method used by meat industry for improving the sensory attributes of meat.Despite the advent of many novel technologies,aging has not lost its charm and is still widely used commercially as a post-mortem intervention for tenderization.Aging improves the tenderness of meat through disruption of the muscle structure by intracellular proteolytic systems.Muscles undergo various molecular changes that cause proteolysis of key myofibrillar and cytoskeletal proteins,disrupting the overall integrity of muscle cells.Although several endogenous proteolytic systems are capable of post-mortem proteolysis,a great body of scientific evidence supports a major role for the calpain system.Calpains are intracellular calcium-dependent cysteine proteases found in most eukaryotes.At least three calpains(μ-and m-calpains and calpain 3)and calpastatin,their specific endogenous inhibitor,are found in muscle.They are known to be involved in the proteolysis of functionally relevant structural proteins such as the myofibrillar proteins and cytoskeletal anchorage complexes.These ubiquitous proteases are also present in mitochondria and play important roles in a variety of pathophysiological conditions including apoptotic and necrotic cell death phenomena.This review discusses the role and contribution of the calpain system and the factors that influence calpain activity during aging.

Molecular chaperones and hypoxic-ischemic encephalopathy

Hypoxic-ischemic encephalopathy（HIE） is a disease that occurs when the brain is subjected to hypoxia,resulting in neuronal death and neurological deficits,with a poor prognosis.The mechanisms underlying hypoxic-ischemic brain injury include excitatory amino acid release,cellular proteolysis,reactive oxygen species generation,nitric oxide synthesis,and inflammation.The molecular and cellular changes in HIE include protein misfolding,aggregation,and destruction of organelles.The apoptotic pathways activated by ischemia and hypoxia include the mitochondrial pathway,the extrinsic Fas receptor pathway,and the endoplasmic reticulum stress-induced pathway.Numerous treatments for hypoxic-ischemic brain injury caused by HIE have been developed over the last half century.Hypothermia,xenon gas treatment,the use of melatonin and erythropoietin,and hypoxic-ischemic preconditioning have proven effective in HIE patients.Molecular chaperones are proteins ubiquitously present in both prokaryotes and eukaryotes.A large number of molecular chaperones are induced after brain ischemia and hypoxia,among which the heat shock proteins are the most important.Heat shock proteins not only maintain protein homeostasis; they also exert anti-apoptotic effects.Heat shock proteins maintain protein homeostasis by helping to transport proteins to their target destinations,assisting in the proper folding of newly synthesized polypeptides,regulating the degradation of misfolded proteins,inhibiting the aggregation of proteins,and by controlling the refolding of misfolded proteins.In addition,heat shock proteins exert anti-apoptotic effects by interacting with various signaling pathways to block the activation of downstream effectors in numerous apoptotic pathways,including the intrinsic pathway,the endoplasmic reticulum-stress mediated pathway and the extrinsic Fas receptor pathway.Molecular chaperones play a key role in neuroprotection in HIE.In this review,we provide an overview of the mechanisms of HIE and discuss the various treatment strategies.Given their critical role in the disease,molecular chaperones are promising therapeutic targets for HIE.