Exploring the Sexual Dimorphism of Crustacean Neuropeptide Expression Using Callinectes sapidus as a Model Organism

The impact of numerous diseases has
been linked to differences
in sex between organisms, including various neurological diseases.
As neuropeptides are known to be key players in the nervous system,
studying the variation of neuropeptidomic profiles between males and
females in a crustacean model organism is of interest. By using high-resolution
mass spectrometry with two complementary ionization sources in conjunction
with quantitative chemical labeling (isotopic reductive dimethylation),
differences were observed in five key neural tissues and hemolymph.
Interestingly, while males and females possess numerous neuropeptide
isoforms that are unique to their sex, the represented families of
each sex remain largely consistent. However, some differences in familial
isoforms were also observed, such as the relative numbers of neuropeptides
belonging to RFamide and allatostatin A-type families. Additionally,
>100 neuropeptides detected across five neural tissues and hemolymph
were found to have statistically significant differences in abundance
between male and female blue crab samples. Also, hundreds of putative
peptide sequences were identified by de novo sequencing
that may be indicative of previously undiscovered neuropeptides, highlighting
the power of using a multifaceted MS approach.

诸多疾病的致病机制均与生物体的性别差异存在关联，各类神经系统疾病亦在此列。鉴于神经肽（neuropeptide）是神经系统的关键调控因子，以甲壳类模式生物为研究对象，探究雌雄个体间的神经肽组谱差异具有重要学术价值。本研究采用搭载两种互补电离源的高分辨质谱（high-resolution mass spectrometry）技术，并结合定量化学标记（quantitative chemical labeling）法——即同位素还原二甲基化（isotopic reductive dimethylation）——对5种关键神经组织与血淋巴（hemolymph）进行分析，最终观测到相关表达差异。值得注意的是，尽管雌雄个体各自拥有大量性别特异性的神经肽同工型，但二者所检测到的神经肽家族整体上大体保持一致。不过，研究同样观测到家族层面的同工型差异，例如RF酰胺（RFamide）与咽侧体抑制素A型（allatostatin A-type）家族的神经肽相对数量存在显著区别。此外，在5种神经组织与血淋巴中检测到的100余种神经肽，在雄性与雌性蓝蟹样本中的表达丰度存在统计学意义上的显著差异。同时，通过从头测序（de novo sequencing）技术鉴定出数百条推定肽序列，这些序列可能代表了此前未被发现的神经肽，这一结果凸显了多维度质谱（MS）分析策略的应用价值。