Advancing Nonsmall Cell Lung Cancer Diagnosis Accuracy via Dual Detection Fluorescent Nanoprobes.

Among the primary threats to human health worldwide, nonsmall cell lung cancer (NSCLC) remains a significant factor and is a leading cause of cancer-related deaths. Due to subtle early symptoms, NSCLC patients are diagnosed at advanced stages, resulting in low survival rates. Herein, novel Au-Se bond nanoprobes (NPs) designed for the specific detection of Calpain-2 (CAPN2) and Human Neutrophil Elastase (HNE), pivotal biomarkers in NSCLC, were developed. The NPs demonstrated exceptional specificity and sensitivity toward CAPN2 and HNE, enabling dual-color fluorescence imaging to distinguish between NSCLC cells and normal lung cells effectively. The NPs' performance was consistent across a wide pH range (6.2 to 8.0), and it exhibited remarkable resistance to biological thiol interference, indicating its robustness in complex physiological environments. These findings suggest the nanoprobe is a promising tool for early NSCLC diagnosis, offering a novel approach for enhancing the accuracy of cancer detection.

Companion Diagnosis for Retinal Neuroprotective Treatment by Real-Time Imaging of Calpain Activation Using a Novel Fluorescent Probe.

Calpain activation induces retinal ganglion cell (RGC) death, while calpain inhibition suppresses RGC death, in animal studies. However, the role of calpain in human retinal disease is unclear. This study investigated a new strategy to study the role of calpain based on real-time imaging. We synthesized a novel fluorescent probe for calpain, acetyl-l-leucyl-l-methionine-hydroxymethyl rhodamine green (Ac-LM-HMRG) and used it for real-time imaging of calpain activation. The toxicity of Ac-LM-HMRG was evaluated with a lactate dehydrogenase cytotoxicity assay, retinal sections, and electroretinograms. Here, we performed real-time imaging of calpain activation in a rat model. First, we administered N-methyl-d-aspartate (NMDA) to induce retinal injury. Twenty minutes later, we administered an intravitreal injection of Ac-LM-HMRG. Real-time imaging was then completed with a noninvasive confocal scanning laser ophthalmoscope. The inhibitory effect of SNJ-1945 against calpain activation was also examined with the same real-time imaging method. Ac-LM-HMRG had no toxic effects. The number of Ac-LM-HMRG-positive cells in real-time imaging significantly increased after NMDA injury, and SNJ-1945 significantly lowered the number of Ac-LM-HMRG-positive cells. Real-time imaging with Ac-LM-HMRG was able to quickly quantify the NMDA-induced activation of calpain and the inhibitory effect of SNJ-1945. This technique, used as a companion diagnostic system, may aid research into the development of new neuroprotective therapies.

Calpain activation and proteolysis in postmortem goose muscles.

Meat tenderness is considered as the most important criterion for meat quality by consumers and can be improved by the actions of endogenous proteases, mainly calpains, during postmortem storage at 0-5°C. The purpose of this study, therefore, was to examine the postmortem calpain activation and proteolysis in breast (BM) and leg and thigh (LM) muscles of White Roman goose. BM and LM were taken from goose carcasses (n = 15) at 0 (10-15 min postmortem), 1, 3, and 7 days of storage at 5°C. The decrease in postmortem pH, calpain-1 and -11 activities, and contents of the calpain-1 80 kDa subunit and desmin was more rapid (p < .05) in BM than in LM. Our results show that postmortem proteolysis was more extensive in BM than in LM of White Roman goose, not only because the difference in fiber type composition between two muscles, but because the rate and extent of calpain activation were greater in BM as well. These results may provide useful information to optimize meat processing for different muscles in goose industry.

Acoustic biosensors for ultrasound imaging of enzyme activity.

Visualizing biomolecular and cellular processes inside intact living organisms is a major goal of chemical biology. However, existing molecular biosensors, based primarily on fluorescent emission, have limited utility in this context due to the scattering of light by tissue. In contrast, ultrasound can easily image deep tissue with high spatiotemporal resolution, but lacks the biosensors needed to connect its contrast to the activity of specific biomolecules such as enzymes. To overcome this limitation, we introduce the first genetically encodable acoustic biosensors-molecules that 'light up' in ultrasound imaging in response to protease activity. These biosensors are based on a unique class of air-filled protein nanostructures called gas vesicles, which we engineered to produce nonlinear ultrasound signals in response to the activity of three different protease enzymes. We demonstrate the ability of these biosensors to be imaged in vitro, inside engineered probiotic bacteria, and in vivo in the mouse gastrointestinal tract.

Protein degradation and structure changes of beef muscle during superchilled storage.

This study investigated the effect of superchilled storage (-4 °C) on protein degradation and structural changes of beef steaks from M. longissimus lumborum compared with traditional chilling (2 °C) and frozen storage (-18 °C). Traditional chilling induced significantly greater degradation of troponin T and desmin, and more rapid loss of calpain activity, compared to superchilled or frozen storage treatments. The proteolysis of key myofibrillar proteins resulted in a sharp decline of WBSF values during traditional chilled storage. For frozen beef samples, no major changes were observed with respect to protein degradation or muscle structure during storage. However, superchilled samples exhibited wider gaps between muscle fibers at 12 weeks storage, associated with muscle fiber shrinkage.

Effects of electrical stimulation and pre-rigor conditioning temperature on aging potential of hot-boned beef M. longissimus lumborum.

The objective of this study was to create various pH/temp decline rates in hot-boned bull beef M. longissimus lumborum (LL) through a combination of electrical stimulation (ES) and pre-rigor holding temperature. The relationship between the pre-rigor interventions, the activities of µ-calpain and small heat shock proteins (sHSP), and the impacts on meat product quality were determined. Paired LL loins from 13 bulls were hot-boned within 40 min of slaughter, immediately ES and subjected to various holding temperatures (5, 15, 25, and 35°C) for 3 hr. The rate of muscle pH decline, sarcomere length, shear force, and proteolysis of muscle proteins were measured. ES-25°C had a longer sarcomere length compared to non-electrical stimulation samples. ES-25°C and ES-35°C samples had lower shear force values, higher µ-calpain activity and higher desmin, troponin-T, and sHSP degradation. The above findings suggest that pH/temp decline rates created in hot-boned muscle impacted muscle protein proteolysis by increasing the activity of proteases and degradation of sHSP.

Calpain 1 in bronchoalveolar lavage fluid is associated with poor prognosis in lepidic predominant pulmonary adenocarcinoma.

Calpain 1 is a proinflammatory calcium-activated cysteine protease, which can be partly externalized. Extracellular calpains limit inflammatory processes and promote tissue repair, through cell proliferation and migration. Toll like receptor (TLR) 2 has been identified as a target of extracellular calpains in lymphocytes. The aim was to investigate the externalization of calpain 1 and the release of soluble TLR2 during tumor progression of pulmonary lepidic predominant adenocarcinoma (LPA). Extracellular calpain 1, soluble fragment of TLR2 and cytokines were analyzed by ELISA in bronchoalveolar lavage fluid (BALF) supernatants from patients with LPA (n=68). Source of calpain was analyzed by immunohistochemistry and soluble TLR2 by flow cytometry on polymorphonuclear neutrophils (PMN) and human lung cancer cell lines. Extracellular calpain 1, secreted by tumor cells, was associated to tumor progression, neutrophilic inflammation, with a poor prognostic factor on survival (P=0.003). TLR2 was expressed on PMN and tumor cells and decreased after calpain exposure. Soluble fragment of TLR2 in BALF supernatants was correlated to the extracellular calpain 1 concentration (r=0.624; P<0.001), and its high level was associated with tumor progression and a pro-inflammatory environment. Extracellular calpain 1 secreted by tumor cells, could participate in inflammatory microenvironment and tumor progression through TLR2 in LPA.

Effects of frozen-then-chilled storage on proteolytic enzyme activity and water-holding capacity of pork loin.

This study aimed to determine the effect of frozen-then-chilled storage on free Ca2+, proteolytic enzyme activity of calpains and the proteasome, water-holding capacity and shear force of porcine longissimus thoracis et lumborum muscle. Pork loins were subjected to either chilled storage at 2 ±â€¯1 °C for 1, 2, 4, 6 and 9 days, or frozen-then chilled storage (-20 ±â€¯1 °C for 1 week followed by thawing overnight). Free Ca2+ increased with chilled storage in the non-frozen group. Frozen-then-chilled storage increased free Ca2+ concentration, followed by a faster decrease of calpain-1 activity and activation of around 50% of calpain-2. Proteasome activity was reduced by around 40% following freezing-thawing. Purge loss increased and water-holding capacity of myofibrils decreased in the frozen-thawed group, suggesting considerable denaturation of myofibrillar proteins. Shear force was not affected by freezing-thawing, and we speculate that the tenderizing effect of calpain activation was counteracted by loss of proteasome activity and substantial exudate loss.

Cytoplasmic FOXP1 expression is correlated with ER and calpain II expression and predicts a poor outcome in breast cancer.

BACKGROUND: Nuclear forkhead box protein P1 (N-FOXP1) expression in invasive breast cancer has been documented in the literature. However, the FOXP1 expression patterns at different stages of breast cancer progression are largely unknown, and the significance of cytoplasmic FOXP1 (C-FOXP1) expression in breast cancer has not been well illustrated. The aims of this study were to investigate FOXP1 expression patterns in invasive ductal carcinoma (IDC), ductal carcinoma in situ (DCIS), atypical ductal hyperplasia (ADH) and usual ductal hyperplasia (UDH), and to analyze the clinicopathological relevance of C-FOXP1 and its prognostic value in IDC. METHODS: N-FOXP1 and C-FOXP1 expression in cases of IDC, DCIS, ADH and UDH was determined using immunohistochemistry. The correlation between C-FOXP1 expression and clinicopathological parameters as well as the overall survival (OS) and disease-free survival (DFS) rates of patients with IDC were analyzed. RESULTS: Exclusive N-FOXP1 expression was found in 85.0% (17/20), 40.0% (8/20), 12.2% (5/41) and 10.8% (9/83) of UDH, ADH, DCIS, and IDC cases, respectively, and exclusive C-FOXP1 expression was observed in 0% (0/20), 0% (0/20), 4.9% (2/41), and 31.3% (26/83) of the cases, respectively. Both N- and C-FOXP1 staining were observed in 15.0% (3/20), 60.0% (12/20), 82.9% (34/41) and 48.2% (40/83) of the above cases, respectively, while complete loss of FOXP1 expression was observed in only 9.6% (8/83) of IDC cases. Estrogen receptor (ER) expression in C-FOXP1-positive IDC cases (31/66, 47.0%) was significantly lower than that in C-FOXP1-negative cases (13/17, 76.5%) (p = 0.030). Calpain II expression was observed in 83.3% (55/66) of C-FOXP1-positive IDC cases, which was significantly higher than that in C-FOXP1-negative cases (9/17, 52.9%) (p = 0.007). Calpain II was significantly associated with pAKT (p = 0.029), pmTOR (p = 0.011), p4E-BP1 (p < 0.001) and p-p70S6K (p = 0.003) expression levels. The 10-year OS and DFS rates of the C-FOXP1-positive patients were 60.5% and 48.7%, respectively, both of which were lower than those of the C-FOXP1-negative patients (93.3, 75.3%). The OS curve showed a dramatic impact of C-FOXP1 status on OS (p = 0.045). CONCLUSIONS: Cytoplasmic relocalization of FOXP1 protein was a frequent event in breast IDC. Calpain II might play an important role in nucleocytoplasmic trafficking of FOXP1 and the AKT pathway might be involved in this process. C-FOXP1 expression was inversely associated with ER expression and might be a predictor of poor OS in patients with IDC.

Early-life regional and temporal variation in filaggrin-derived natural moisturizing factor, filaggrin-processing enzyme activity, corneocyte phenotypes and plasmin activity: implications for atopic dermatitis.

BACKGROUND: Filaggrin is central to the pathogenesis of atopic dermatitis (AD). The cheeks are a common initiation site of infantile AD. Regional and temporal expression of levels of filaggrin degradation products [natural moisturizing factors (NMFs)], activities of filaggrin-processing enzymes [bleomycin hydrolase (BH) and calpain-1 (C-1)] and plasmin, and corneocyte envelope (CE) maturity in early life are largely unknown. OBJECTIVES: We conducted a cross-sectional, observational study investigating regional and age-dependent variations in NMF levels, activity of proteases and CE maturity in stratum corneum (SC) from infants to determine whether these factors could explain the observed predilection sites for AD in early life. METHODS: We measured NMF using a tape-stripping method at seven sites in the SC of 129 children (aged < 12 months to 72 months) and in three sites in 56 neonates and infants (< 48 h to 3 months). In 37 of these neonates and infants, corneocyte size, maturity, BH, C-1 and plasmin activities were determined. RESULTS: NMF levels are low at birth and increase with age. Cheek SC, compared with elbow flexure and nasal tip, has the lowest NMF in the first year of life and is the slowest to reach stable levels. Cheek corneocytes remain immature. Plasmin, BH and C-1 activities are all elevated by 1 month of age in exposed cheek skin, but not in elbow skin. CONCLUSIONS: Regional and temporal differences in NMF levels, CE maturity and protease activities may explain the predilection for AD to affect the cheeks initially and are supportive of this site as key for allergen priming in early childhood. These observations will help design early intervention and treatment strategies for AD.

A new insight into meat toughness of callipyge lamb loins - The relevance of anti-apoptotic systems to decreased proteolysis.

The objective of this study was to determine associations of small heat shock proteins (sHSPs) in tenderness development of loins from callipyge and normal genotype lambs. Loins (M. longissimus lumborum) from sixteen lambs across four genotypes were collected throughout 9 days of postmortem aging. The loins from callipyge lambs had more intact desmin and troponin T throughout aging periods, as well as less µ-calpain autolysis and more calpastatin compared to loins from other genotypes (P < 0.05). Delayed onset of apoptosis was found in the callipyge loins indicated by less cytochrome c and more inactive procaspase-3 compared to normal lamb loins (P < 0.05). Less degraded HSP27 was also consistently found in the callipyge loins compared with loins from normal lambs (P < 0.001). The results found up-regulation of anti-apoptotic activities coincided with toughness in callipyge loins, which suggest apoptosis is likely involved in postmortem proteolysis and subsequent meat tenderization.

Evolution of proteolytic indicators during storage of broiler wooden breast meat.

In the past few yr, an emerging muscle abnormality termed wooden breast (WB) was found to affect broilers' Pectoralis major muscles. Although different studies have been performed in order to evaluate the effect of WB on meat quality, there is no evidence concerning its impact on the proteolytic processes taking place during meat aging. Thus, this study aimed at investigating the effect of a 7-day storage of broiler breast fillets on free calcium concentration, calpain activity, and proteolysis. Both the superficial and the deep layers of the Pectoralis major muscles were considered. Although similar electrophoretic profiles were observed by comparing the corresponding sampling positions, an evident lack of a high-molecular weight protein band, ascribed to nebulin, was found in the superficial layer of the WB fillets at 10 h postmortem. Compared to normal fillets (NB), both the superficial and the deep layer of WB exhibited a significantly higher amount of free calcium at 168 h postmortem (96 and 88 vs. 20 and 53 µM; P ≤ 0.001). Casein zymograms evidenced the presence of µ/m-calpain and its autolyzed form migrating as a doublet within the gel. Interestingly, neither the occurrence of WB nor the intra-fillet sampling position exerted any relevant effect on calpain activity. Indeed, a significant reduction (P ≤ 0.05) in the unautolyzed µ/m-calpain activity coupled with a remarkable increase (P ≤ 0.05) in the autolyzed form activity was observed during storage. Concurrently, if compared to NB, a significantly larger (P ≤ 0.05) amount of desmin was detected in both the superficial and the deep layers of the WB samples at 10 h postmortem. Then, a sharp decrease of the intact desmin band coupled with a progressive accumulation of its 39-kDa degradation fragment was observed without any significant difference among groups. In conclusion, the increased hardness that typically affects the WB cases seemed not to be exclusively attributable to differences in the proteolytic processes taking place within the postmortem period.

Effect of negative dietary cation-anion differences on carcass characteristics and beef tenderness of Japanese Black steers.

Lowering dietary cation-anion differences (DCAD) can enhance responsiveness to Ca-homeostatic hormones and increase Ca availability, which might have potential to activate a Ca-dependent protease, calpain, and to enhance postmortem myofibrillar proteolysis. In this study, we investigated the effects of DCAD manipulation on calpain activity and beef tenderness in Japanese Black cattle which are characterized by their high marbling. Thirty-six Japanese Black steers were allotted to one of two treatments: (i) control (CON; DCAD +6.09 mEq/100 g of dry matter (DM)) or (ii) negative DCAD (NEGD; DCAD -8.27 mEq/100 g DM) for 70 days before slaughter. Lowering DCAD decreased DM and energy intake (P < 0.01) even though it did not negatively affect the growth performance or carcass characteristics. In NEGD, urine pH was decreased by acidification caused by the negative DCAD (P < 0.01). Calpain activities tended to be improved in NEGD (P = 0.09), but Warner-Bratzler shear force values were not affected by treatment. Although calpain activities tended to improve, lowering DCAD to -8.27 for 70 days before slaughter was insufficient to enhance beef tenderness in Japanese Black steers.

Involvement of µ/m-calpain in the proteolysis and meat quality changes during postmortem storage of chicken breast muscle.

The objective of this study was to investigate the role of calpain isotypes, especially poultry-specific µ/m-calpain in the proteolysis and meat quality changes of chicken breast muscle during postmortem storage. Calpain activity was detected by casein zymography, while the degradation of titin, desmin and Troponin-T was analyzed by sodium dodecyl sulfate - polyacrylamide gel electrophoresis and western blot. Meat quality indicators such as water holding capacity and tenderness were also studied. The correlation analysis between calpain activity, proteolysis and the changes in meat quality indicators indicated that there were strong correlations for µ-calpain during the first 12 h of storage, while such strong correlations for µ/m-calpain were only found in samples stored from 12 h to 7 days. Our study suggested that µ-calpain played a major role in meat quality changes while µ/m-calpain could also be involved but played a limited role in the proteolysis and meat quality changes during 12 h to 7 days postmortem storage of chicken breast muscle.

Identification and Functional Validation of a Biomarker for the Diagnosis of Miltefosine Relapse during Visceral Leishmaniasis.

Miltefosine is the only orally administrable drug for the treatment of leishmaniasis. But in recent years, a decline in its efficacy points toward the emergence of resistance to this drug. Knowledge of biomarkers for miltefosine resistance may be beneficial for proper selection of treatment regimen. Splenic aspirates were collected and parasites cultured from patients relapsed after initial cure (N = 15) and successfully treated (N = 15) with miltefosine. Differential expression of genes in miltefosine-resistant strains was examined by DNA microarray and validated by real-time reverse transcription polymerase chain reaction and Western blotting. Of 669 upregulated genes, the cysteine protease-like protein of calpain family (GenBank: CBZ34784) was found to be significantly overexpressed in resistant parasite strains and only anti-calpain antibodies showed its presence in the sera of relapse patients through Western blotting. Calpain family cysteine protease-like protein can be useful as a potential biomarker of miltefosine unresponsiveness.

Calpain Zymography: General Methodology and Protocol.

Casein zymography has become one of the gold standard assays for monitoring mammalian calcium-activated proteases (calpains) in purified enzyme, cell, or tissue samples. This calpain zymography method takes advantages of (1) casein is an excellent substrate for major isoforms of calpains (Calpain-1, 2 and 3), (2) the embedded casein is digested into small peptides where the calpain bands are located, thus creating a clear zone upon Commassie blue gel staining, and (3) the calpain isoforms have different gel mobility under native gel conditions. Casein zymography is also useful in studying reversibility of inhibitor binding to calpains.

Protective effects of Tongxinluo on cerebral ischemia/reperfusion injury related to Connexin 43/Calpain II/Bax/Caspase-3 pathway in rat.

ETHNOPHARMACOLOGICAL RELEVANCE: Tongxinluo (TXL) is a multifunctional traditional Chinese medicine and has been widely used in the treatment of cardiovascular and cerebrovascular diseases. Numerous studies demonstrate that TXL is a novel neuroprotective drug, however, the mechanisms are largely unknown. AIM OF THE STUDY: we aimed to demonstrate the protective effect of TXL on cerebral ischemia/reperfusion (I/R) injury and provide the evidence for the involvement of Connexin 43/Calpain II/ Bax/Caspase-3 pathway in TXL-mediated neuroprotection. METHODS: Focal cerebral I/R injury were induced by transient middle cerebral artery occlusion (MCAO, for 90min) in adult male Sprague-Dawley rats. We estimated the effects of TXL on I/R injury including neurological deficit assessment and cerebral infarct volume measurement via TTC staining, and detected the protein expression of Connexin 43 (Cx43) by western blot. Furthermore, after the intracerebroventricular injection of carbenoxolone (CBX, the inhibitor of Cx43) at 30min before MCAO surgery, Calpain II, Bax and cleaved Caspased-3 immunoreactivity in ischemic penumbra region was detected by immunofluorescent staining, and cell apoptosis was detected by TUNEL staining. RESULTS: TXL treatment greatly improved neurological deficit and reduced the infarction volume compared to MCAO with buffer treatment (P<0.05), and TXL pre-post treatment showed better results than TXL pre-treatment. TXL pre-post treatment significantly up-regulated Cx43 protein expression at 3d, 7d and 14d post-injury compared to MCAO with buffer treatment (P<0.05). Meanwhile, the immunoreactivity of Calpain II, Bax and cleaved Caspase-3 in ischemic penumbra region was obviously decreased by TXL pre-post treatment compared to MCAO group (P<0.05). However, with the treatment of the Cx43 inhibitor, CBX, the down-regulated effect of TXL on Calpain II, Bax and cleaved Caspase-3 immunoreactivity was abolished (P<0.05). Moreover, the protective effect of TXL against neuron apoptosis in penumbra region was conteracted by CBX (P<0.05). CONCLUSIONS: TXL could effectively protect against I/R injury and reduced cell death via Cx43/Calpain II/Bax/Caspase-3 pathway, which contribute to I/R injury prevention and therapy.

Caspase-3 and caspase-8 expression in breast cancer: caspase-3 is associated with survival.

Impaired apoptosis is one of the hallmarks of cancer. Caspase-3 and -8 are key regulators of the apoptotic response and have been shown to interact with the calpain family, a group of cysteine proteases, during tumorigenesis. The current study sought to investigate the prognostic potential of caspase-3 and -8 in breast cancer, as well as the prognostic value of combinatorial caspase and calpain expression. A large cohort (n = 1902) of early stage invasive breast cancer patients was used to explore the expression of caspase-3 and -8. Protein expression was examined using standard immunohistochemistry on tissue microarrays. High caspase-3 expression, but not caspase-8, is significantly associated with adverse breast cancer-specific survival (P = 0.008 and P = 0.056, respectively). Multivariate analysis showed that caspase-3 remained an independent factor when confounding factors were included (hazard ratio (HR) 1.347, 95% confidence interval (CI) 1.086-1.670; P = 0.007). The analyses in individual subgroups demonstrated the significance of caspase-3 expression in clinical outcomes in receptor positive (ER, PR or HER2) subgroups (P = 0.001) and in non-basal like subgroup (P = 0.029). Calpain expression had been previously assessed. Significant association was also found between high caspase-3/high calpain-1 and breast cancer-specific survival in the total patient cohort (P = 0.005) and basal-like subgroup (P = 0.034), as indicated by Kaplan-Meier analysis. Caspase-3 expression is associated with adverse breast cancer-specific survival in breast cancer patients, and provides additional prognostic values in distinct phenotypes. Combinatorial caspase and calpain expression can predict worse prognosis, especially in basal-like phenotypes. The findings warrant further validation studies in independent multi-centre patient cohorts.

Deimination of Human Hornerin Enhances its Processing by Calpain-1 and its Cross-Linking by Transglutaminases.

Hornerin (HRNR) shares numerous features with filaggrin, a key contributor to the epidermal barrier functions. The two proteins display a related structural organization, are expressed by the granular keratinocytes as a large precursor processed by proteolysis, and are cross-linked to the cornified cell envelopes. Two main steps in the metabolism of filaggrin are its deimination and calpain-1 cleavage. Here, using ion-exchange chromatography and two-dimensional gel electrophoresis of human epidermis extracts, we determined that HRNR is deiminated in vivo. Accordingly, cornified envelopes, purified from plantar and abdominal human skin, were shown to contain deiminated proteins. A recombinant form of HRNR (HRNRHis) deiminated in vitro was shown to be a better substrate for transglutaminases 1 and 3 than the unmodified form. Our data also indicated that calpain-1 may be involved in the proteolytic processing of HRNR, because calpain-1 was co-located with HRNR in the cytoplasm of granular keratinocytes. Using Western blotting and mass spectrometry analysis, HRNRHis was shown to be cleaved by calpain-1 in vitro, its deimination enhancing its proteolysis. In HRNR full sequence, four calpain-1 cleavage sites were identified. Altogether, these data allowed a new role to be deciphered for deimination during cornification and provided further characterization of HRNR metabolism.

[Effect of leptin on expression of calpain-1 and Bcl-2 and apoptosis in myocardial tissue of neonatal rats after asphyxia].

OBJECTIVE: To study the effect of leptin on the expression of calcium-activated neutral protease 1 (calpain-1) and B cell lymphoma-2 (Bcl-2) and apoptosis in the myocardial tissue of neonatal rats after asphyxia. METHODS: A total of 48 neonatal rats were randomly and equally divided into normal control group, asphyxia group, leptin treatment groups, and calpain-1 inhibitor (CAI-1) group. The neonatal rat model of asphyxia under normal atmospheric condition was established in all groups except the control group. For the leptin treatment groups, rats received 20, 80, and 160 µg/kg leptin by intraperitoneal injection immediately after model establishment, respectively. For the CAI-1 group, rats received 10 mg/kg CAI-1 by intraperitoneal injection immediately after model establishment. For all the groups, the myocardial tissue was collected at 2 hours after model establishment. Immunohistochemistry was used to measure the expression of calpain-1 and Bcl-2. The TUNEL method was used to evaluate apoptosis of myocardial cells. RESULTS: The expression of calpain-1 and Bcl-2 and apoptosis index (AI) were significantly higher in the asphyxia group than in the normal control group (P˂0.05). The leptin treatment groups and the CAI-1 group had significantly lower expression of calpain-1, significantly lower AI, and significantly higher expression of Bcl-2 than the asphyxia group (P˂0.05). The CAI-1 group had the largest changes in all the indices compared with the asphyxia group. However, there were no significant differences in all indices between the 160 µg/kg leptin treatment group and the CAI-1 group. After asphyxia, the expression of calpain-1 was positively correlated with AI, while the expression of Bcl-2 was negatively correlated with AI and the expression of calpain-1 (P˂0.05). CONCLUSIONS: Leptin reduces apoptosis of myocardial cells in asphyxiated neonatal rats by the inhibition of calpain-1 activation and upregulation of Bcl-2 expression.